Associative array/Iteration: Difference between revisions
Content deleted Content added
| (232 intermediate revisions by more than 100 users not shown) | |||
Line 1:
[[Category:Data Structures]]
{{task|Basic language learning}}Show how to iterate over the key-value pairs of an associative array, and print each pair out.
Also show how to iterate just over the keys, or the values, if there is a separate way to do that in your language.
{{Template:See also lists}}
<br><br>
=={{header|11l}}==
<syntaxhighlight lang="11l">V d = [‘key1’ = ‘value1’, ‘key2’ = ‘value2’]
L(key, value) d
print(key‘ = ’value)
L(key) d.keys()
print(key)
L(value) d.values()
print(value)</syntaxhighlight>
{{out}}
<pre>
key1 = value1
key2 = value2
key1
key2
value1
value2
</pre>
=={{header|8th}}==
Iterating key,value pairs uses "m:each":
<syntaxhighlight lang="forth">
{"one": 1, "two": "bad"}
( swap . space . cr )
m:each
</syntaxhighlight>
{{out}}<pre>
one 1
two bad
</pre>
Iterating the keys uses "m:keys":
<syntaxhighlight lang="forth">
{"one": 1, "two": "bad"} m:keys
( . cr )
a:each
</syntaxhighlight>
{{out}}<pre>
one
two
</pre>
=={{header|Ada}}==
<
with Ada.Containers.Indefinite_Ordered_Maps;
Line 23 ⟶ 72:
Index := Next (Index);
end loop;
end Test_Iteration;</
{{out}}
<pre>
! 3
Line 30 ⟶ 79:
world 2
</pre>
=={{header|Aime}}==
<syntaxhighlight lang="aime">record r;
text s;
r_put(r, "A", 33); # an integer value
r_put(r, "C", 2.5); # a real value
r_put(r, "B", "associative"); # a string value
if (r_first(r, s)) {
do {
o_form("key ~, value ~ (~)\n", s, r[s], r_type(r, s));
} while (rsk_greater(r, s, s));
}</syntaxhighlight>
{{out}}
<pre>key A, value 33 (integer)
key B, value associative (text)
key C, value 2.5 (real)</pre>
=={{header|ALGOL 68}}==
Algol 68 does not have associative arrays as standard.
<br>
This sample defines a simple hash-based implementation with operators to iterate over the array.
<syntaxhighlight lang="algol68"># associative array handling using hashing #
# the modes allowed as associative array element values - change to suit #
MODE AAVALUE = STRING;
# the modes allowed as associative array element keys - change to suit #
MODE AAKEY = STRING;
# nil element value #
REF AAVALUE nil value = NIL;
# an element of an associative array #
MODE AAELEMENT = STRUCT( AAKEY key, REF AAVALUE value );
# a list of associative array elements - the element values with a #
# particular hash value are stored in an AAELEMENTLIST #
MODE AAELEMENTLIST = STRUCT( AAELEMENT element, REF AAELEMENTLIST next );
# nil element list reference #
REF AAELEMENTLIST nil element list = NIL;
# nil element reference #
REF AAELEMENT nil element = NIL;
# the hash modulus for the associative arrays #
INT hash modulus = 256;
# generates a hash value from an AAKEY - change to suit #
OP HASH = ( STRING key )INT:
BEGIN
INT result := ABS ( UPB key - LWB key ) MOD hash modulus;
FOR char pos FROM LWB key TO UPB key DO
result PLUSAB ( ABS key[ char pos ] - ABS " " );
result MODAB hash modulus
OD;
result
END; # HASH #
# a mode representing an associative array #
MODE AARRAY = STRUCT( [ 0 : hash modulus - 1 ]REF AAELEMENTLIST elements
, INT curr hash
, REF AAELEMENTLIST curr position
);
# initialises an associative array so all the hash chains are empty #
OP INIT = ( REF AARRAY array )REF AARRAY:
BEGIN
FOR hash value FROM 0 TO hash modulus - 1 DO ( elements OF array )[ hash value ] := nil element list OD;
array
END; # INIT #
# gets a reference to the value corresponding to a particular key in an #
# associative array - the element is created if it doesn't exist #
PRIO // = 1;
OP // = ( REF AARRAY array, AAKEY key )REF AAVALUE:
BEGIN
REF AAVALUE result;
INT hash value = HASH key;
# get the hash chain for the key #
REF AAELEMENTLIST element := ( elements OF array )[ hash value ];
# find the element in the list, if it is there #
BOOL found element := FALSE;
WHILE ( element ISNT nil element list )
AND NOT found element
DO
found element := ( key OF element OF element = key );
IF found element
THEN
result := value OF element OF element
ELSE
element := next OF element
FI
OD;
IF NOT found element
THEN
# the element is not in the list #
# - add it to the front of the hash chain #
( elements OF array )[ hash value ]
:= HEAP AAELEMENTLIST
:= ( HEAP AAELEMENT := ( key
, HEAP AAVALUE := ""
)
, ( elements OF array )[ hash value ]
);
result := value OF element OF ( elements OF array )[ hash value ]
FI;
result
END; # // #
# returns TRUE if array contains key, FALSE otherwise #
PRIO CONTAINSKEY = 1;
OP CONTAINSKEY = ( REF AARRAY array, AAKEY key )BOOL:
BEGIN
# get the hash chain for the key #
REF AAELEMENTLIST element := ( elements OF array )[ HASH key ];
# find the element in the list, if it is there #
BOOL found element := FALSE;
WHILE ( element ISNT nil element list )
AND NOT found element
DO
found element := ( key OF element OF element = key );
IF NOT found element
THEN
element := next OF element
FI
OD;
found element
END; # CONTAINSKEY #
# gets the first element (key, value) from the array #
OP FIRST = ( REF AARRAY array )REF AAELEMENT:
BEGIN
curr hash OF array := LWB ( elements OF array ) - 1;
curr position OF array := nil element list;
NEXT array
END; # FIRST #
# gets the next element (key, value) from the array #
OP NEXT = ( REF AARRAY array )REF AAELEMENT:
BEGIN
WHILE ( curr position OF array IS nil element list )
AND curr hash OF array < UPB ( elements OF array )
DO
# reached the end of the current element list - try the next #
curr hash OF array +:= 1;
curr position OF array := ( elements OF array )[ curr hash OF array ]
OD;
IF curr hash OF array > UPB ( elements OF array )
THEN
# no more elements #
nil element
ELIF curr position OF array IS nil element list
THEN
# reached the end of the table #
nil element
ELSE
# have another element #
REF AAELEMENTLIST found element = curr position OF array;
curr position OF array := next OF curr position OF array;
element OF found element
FI
END; # NEXT #
# test the associative array #
BEGIN
# create an array and add some values #
REF AARRAY a1 := INIT LOC AARRAY;
a1 // "k1" := "k1 value";
a1 // "z2" := "z2 value";
a1 // "k1" := "new k1 value";
a1 // "k2" := "k2 value";
a1 // "2j" := "2j value";
# iterate over the values #
REF AAELEMENT e := FIRST a1;
WHILE e ISNT nil element
DO
print( ( " (" + key OF e + ")[" + value OF e + "]", newline ) );
e := NEXT a1
OD
END</syntaxhighlight>
{{out}}
<pre>
(2j)[2j value]
(k1)[new k1 value]
(k2)[k2 value]
(z2)[z2 value]
</pre>
=={{header|App Inventor}}==
Associative arrays in App Inventor are lists of ''key:value'' 'pairs'.<br>
When a list is organized as pairs, the '''lookup in pairs''' block can be used to retrieve an associated value from a key name.<br>
[https://lh3.googleusercontent.com/-Cxw_-XGMRyM/UutOX1bEH9I/AAAAAAAAJ9g/MZotfuSEziY/s1600/CreateIterateLookup.PNG '''<VIEW BLOCKS AND ANDROID APP>''']
=={{header|Arturo}}==
<syntaxhighlight lang="rebol">; create a dictionary
d: #[
name: "john"
surname: "doe"
age: 34
]
; Iterate over key/value pairs
loop d [key,value][
print ["key =" key ", value =" value]
]
print "----"
; Iterate over keys
loop keys d [k][
print ["key =" k]
]
print "----"
; Iterate over values
loop values d [v][
print ["value =" v]
]</syntaxhighlight>
{{out}}
<pre>key = name , value = john
key = surname , value = doe
key = age , value = 34
----
key = name
key = surname
key = age
----
value = john
value = doe
value = 34</pre>
=={{header|ATS}}==
See [[Associative_array/Creation#ATS|Associative_array/Creation#ATS]].
=={{header|AutoHotkey}}==
{{works with|AutoHotkey_L}}
From the [http://www.autohotkey.net/~Lexikos/AutoHotkey_L/docs/objects/Enumerator.htm documentation]<
obj := Object("red", 0xFF0000, "blue", 0x0000FF, "green", 0x00FF00)
enum := obj._NewEnum()
While enum[key, value]
t .= key "=" value "`n"
MsgBox % t</
=={{header|AWK}}==
In AWK "arrays" are always associative arrays, and the only way to iterate over them is by keys (''indexes'' in the AWK terminology), in undefined order.
<syntaxhighlight lang="awk">BEGIN {
a["hello"] = 1
a["world"] = 2
a["!"] = 3
# iterate over keys, undefined order
for(key in a) {
print key, a[key]
}
}</
As AWK was often used in (Bourne) shell scripts,
sorting was done by a pipe of two awk programs and the sort command.
Today, 'gawk' allows to set the order of iteration:
<syntaxhighlight lang="awk">BEGIN {
a["hello"] = 1
a["world"] = 2
a["!"] = 3
PROCINFO["sorted_in"] = "@ind_str_asc" # controls index order
# iterate over keys, indices as strings sorted ascending
for(key in a) {
print key, a[key]
}
}</syntaxhighlight>
=={{header|Babel}}==
In Babel, associative arrays are referred to as maps. To create a map from a list-of-lists:
<syntaxhighlight lang="babel">births (('Washington' 1732) ('Lincoln' 1809) ('Roosevelt' 1882) ('Kennedy' 1917)) ls2map ! <</syntaxhighlight>
To iterate over a map, in the primary sense, use the overmap utility. We will copy the map (cp operator) so as not to modify the original:
<syntaxhighlight lang="babel">births cp dup {1 +} overmap !</syntaxhighlight>
To see the results, use the valmap operator:
<syntaxhighlight lang="babel">valmap ! lsnum !</syntaxhighlight>
{{out}}
<pre>( 1918 1733 1883 1810 )</pre>
There are many ways to interact with a map in Babel. Most of these begin by converting the map to a list or list-of-lists. To look up a list of specific values from the map, by key, use the lumapls utility:
<syntaxhighlight lang="babel">births ('Roosevelt' 'Kennedy') lumapls ! lsnum !</syntaxhighlight>
{{out}}
<pre>( 1882 1917 )</pre>
To convert the entire map back to a list of key-value pairs:
<syntaxhighlight lang="babel">births map2ls !</syntaxhighlight>
To view the list:
<syntaxhighlight lang="babel">{give swap << " " << itod << "\n" <<} each</syntaxhighlight>
{{out}}
<pre>Kennedy 1917
Washington 1732
Roosevelt 1882
Lincoln 1809</pre>
To merge two maps together, use the mapmerge utility:
<syntaxhighlight lang="babel">foo (("bar" 17) ("baz" 42)) ls2map ! <
births foo mergemap !</syntaxhighlight>
To view the results:
<syntaxhighlight lang="babel">births map2ls ! {give swap << " " << itod << "\n" <<} each</syntaxhighlight>
{{out}}
<pre>baz 42
Kennedy 1917
bar 17
Washington 1732
Roosevelt 1882
Lincoln 1809</pre>
For more information on maps in Babel, view [https://github.com/claytonkb/clean_babel/blob/master/std.sp std.sp] (see the section titled "map utilities").
=={{header|BASIC}}==
==={{header|BaCon}}===
<syntaxhighlight lang="qbasic">DECLARE associative ASSOC STRING
associative("abc") = "first three"
associative("mn") = "middle two"
associative("xyz") = "last three"
LOOKUP associative TO keys$ SIZE amount
FOR i = 0 TO amount - 1
PRINT keys$[i], ":", associative(keys$[i])
NEXT</syntaxhighlight>
{{out}}
<pre>prompt$ ./assoc
abc:first three
mn:middle two
xyz:last three</pre>
LOOKUP creates a numerically indexed array of the keys of the associative array, with the number of elements stored in the field following the SIZE keyword.
==={{header|BASIC256}}===
''Solution is at [[Associative_array/Creation#BASIC256]]''.
==={{header|BBC BASIC}}===
<syntaxhighlight lang="bbcbasic"> REM Store some values with their keys:
PROCputdict(mydict$, "FF0000", "red")
PROCputdict(mydict$, "00FF00", "green")
PROCputdict(mydict$, "0000FF", "blue")
REM Iterate through the dictionary:
i% = 1
REPEAT
i% = FNdict(mydict$, i%, v$, k$)
PRINT v$, k$
UNTIL i% = 0
END
DEF PROCputdict(RETURN dict$, value$, key$)
IF dict$ = "" dict$ = CHR$(0)
dict$ += key$ + CHR$(1) + value$ + CHR$(0)
ENDPROC
DEF FNdict(dict$, I%, RETURN value$, RETURN key$)
LOCAL J%, K%
J% = INSTR(dict$, CHR$(1), I%)
K% = INSTR(dict$, CHR$(0), J%)
value$ = MID$(dict$, I%+1, J%-I%-1)
key$ = MID$(dict$, J%+1, K%-J%-1)
IF K% >= LEN(dict$) THEN K% = 0
= K%</syntaxhighlight>
=={{header|Bracmat}}==
<syntaxhighlight lang="bracmat">( new$hash:?myhash
& (myhash..insert)$(title."Some title")
& (myhash..insert)$(formula.a+b+x^7)
& (myhash..insert)$(fruit.apples oranges kiwis)
& (myhash..insert)$(meat.)
& (myhash..insert)$(fruit.melons bananas)
& (myhash..remove)$formula
& (myhash..insert)$(formula.x^2+y^2)
& (myhash..forall)
$ (
= key value
. whl
' ( !arg:(?key.?value) ?arg
& put$("key:" !key "\nvalue:" !value \n)
)
& put$\n
)
);</syntaxhighlight>
{{out}}
<pre>key: meat
value:
key: title
value: Some title
key: formula
value: x^2+y^2
key: fruit
value: melons bananas
key: fruit
value: apples oranges kiwis
</pre>
=={{header|Brat}}==
<
#Iterate over key, value pairs
Line 69 ⟶ 510:
h.each_value { v |
p "Value: #{v}"
}</
=={{header|C}}==
''Solution is at [[Associative arrays/Creation/C]]''.
=={{header|C
<syntaxhighlight lang="csharp">using System;
using System.Collections.Generic;
Line 145 ⟶ 549:
}
}
</syntaxhighlight>
=={{header|C++}}==
{{works with|C++11}}
<syntaxhighlight lang="cpp">#include <iostream>
#include <map>
#include <string>
int main() {
std::map<std::string, int> dict {
{"One", 1},
{"Two", 2},
{"Three", 7}
};
dict["Three"] = 3;
std::cout << "One: " << dict["One"] << std::endl;
std::cout << "Key/Value pairs: " << std::endl;
for(auto& kv: dict) {
std::cout << " " << kv.first << ": " << kv.second << std::endl;
}
return 0;
}</syntaxhighlight>
Pre C++11:
<syntaxhighlight lang="cpp">std::map<std::string, int> myDict;
myDict["hello"] = 1;
myDict["world"] = 2;
myDict["!"] = 3;
// iterating over key-value pairs:
for (std::map<std::string, int>::iterator it = myDict.begin(); it != myDict.end(); ++it) {
// the thing pointed to by the iterator is an std::pair<const std::string, int>&
const std::string& key = it->first;
int& value = it->second;
std::cout << "key = " << key << ", value = " << value << std::endl;
}</syntaxhighlight>
=={{header|Ceylon}}==
<syntaxhighlight lang="ceylon">shared void run() {
value myMap = map {
"foo" -> 5,
"bar" -> 10,
"baz" -> 15
};
for(key in myMap.keys) {
print(key);
}
for(item in myMap.items) {
print(item);
}
for(key->item in myMap) {
print("``key`` maps to ``item``");
}
}</syntaxhighlight>
=={{header|Chapel}}==
<syntaxhighlight lang="chapel">var A = [ "H2O" => "water", "NaCl" => "salt", "O2" => "oxygen" ];
for k in A.domain do
writeln("have key: ", k);
for v in A do
writeln("have value: ", v);
for (k,v) in zip(A.domain, A) do
writeln("have element: ", k, " -> ", v);</syntaxhighlight>
{{out}}
have key: O2
have key: NaCl
have key: H2O
have value: oxygen
have value: salt
have value: water
have element: O2 -> oxygen
have element: NaCl -> salt
have element: H2O -> water
=={{header|Clojure}}==
<
(doseq [[k v] {:a 1, :b 2, :c 3}]
(println k "=" v))
Line 157 ⟶ 647:
(doseq [v (vals {:a 1, :b 2, :c 3})]
(println v))
</syntaxhighlight>
=={{header|CoffeeScript}}==
<syntaxhighlight lang="coffeescript">hash =
a: 'one'
b: 'two'
for key, value of hash
console.log key, value
for key of hash
console.log key
</syntaxhighlight>
=={{header|Common Lisp}}==
Line 166 ⟶ 668:
The association list is a list of conses, each of whose <code>car</code> is a key and whose <code>cdr</code> is a value. The standard mapping and print functions can be used to print key/value pairs, keys, and values.
<
(dolist (pair alist)
(destructuring-bind (key . value) pair
Line 173 ⟶ 675:
;; iterate and destructure with loop
(loop for (key . value) in alist
do (format t "~&Key: ~a, Value: ~a." key value))</
===With property lists (plists)===
Line 179 ⟶ 681:
Property lists are lists of alternating keys and values, where each value's key is the element of the list immediately following it. Printing could be done with standard mapping functions, but <code>loop</code>'s destructuring makes things a bit easier.
<
do (format t "~&Key: ~a, Value: ~a." key value))</
===With hash tables===
Line 186 ⟶ 688:
Lisp also has built-in hash tables, and there are several ways to map over these. The first is <code>maphash</code> which takes a function of two arguments (the key and value) and the hash table.
<
(format t "~&Key: ~a, Value: ~a." key value))
hash-table)</
The <code>loop</code> construct also supports extracting key/value pairs from hash tables.
<
do (format t "~&Key: ~a, Value: ~a." key value))</
There is also a macro <code>with-hash-table-iterator</code> which locally binds a name to produce associated keys and values of the hash table; while rarely used, it is the most powerful operation.
<
(loop
(multiple-value-bind (nextp key value) (next-entry)
(if (not nextp)
(return)
(format t "~&Key: ~a, Value: ~a." key value)))))</
===Alternate solution===
I use [https://franz.com/downloads/clp/survey Allegro CL 10.1]
<syntaxhighlight lang="lisp">
;; Project : Associative array/Iteration
(setf x (make-array '(3 2)
:initial-contents '(("hello" 13 ) ("world" 31) ("!" 71))))
(setf xlen (array-dimensions x))
(setf len (car xlen))
(dotimes (n len)
(terpri)
(format t "~a" (aref x n 0))
(format t "~a" " : ")
(format t "~a" (aref x n 1)))
</syntaxhighlight>
Output:
<pre>
hello : 13
world : 31
! : 71
</pre>
=={{header|Crystal}}==
<syntaxhighlight lang="crystal">dict = {'A' => 1, 'B' => 2}
dict.each { |pair|
puts pair
}
dict.each_key { |key|
puts key
}
dict.each_value { |value|
puts value
}</syntaxhighlight>
{{out}}
<pre>{'A', 1}
{'B', 2}
A
B
1
2</pre>
=={{header|D}}==
{{works with|D|2}}
<
void main() {
Line 246 ⟶ 793:
foreach (value; aa.values)
writeln("7) Got value ", value);
}</
=={{header|Dao}}==
<
for(
for( key in dict.keys(); value in dict.values() ) io.writeln( key, value )
dict.iterate { [key, value]
io.writeln( key, value )
}
</syntaxhighlight>
=={{header|Dart}}==
<syntaxhighlight lang="javascript">
main(){
var fruits = {
'apples': 'red',
'oranges': 'orange',
'bananas': 'yellow',
'pears': 'green',
'plums': 'purple'
};
print('Key Value pairs:');
fruits.forEach( (fruits, color) => print( '$fruits are $color' ) );
print('\nKeys only:');
fruits.keys.forEach( ( key ) => print( key ) );
print('\nValues only:');
fruits.values.forEach( ( value ) => print( value ) );
}
</syntaxhighlight>
{{out}}
<pre>
Key Value pairs:
apples are red
oranges are orange
bananas are yellow
pears are green
plums are purple
Keys only:
apples
oranges
bananas
pears
plums
Values only:
red
orange
yellow
green
purple
</pre>
=={{header|Delphi}}==
<
{$APPTYPE CONSOLE}
Line 280 ⟶ 876:
Writeln('Key: ' + s);
for i in lDictionary.Values do
Writeln('Value: ',
finally
lDictionary.Free;
end;
end.</
=={{header|Dyalect}}==
<syntaxhighlight lang="dyalect">var t = (x: 1, y: 2, z: 3)
for x in t.Keys() {
print("\(x)=\(t[x])")
}</syntaxhighlight>
{{out}}
<pre>x=1
y=2
z=3</pre>
=={{header|E}}==
Line 292 ⟶ 902:
The <code>for</code> loop takes either one pattern, for the value, or two, for the key and value; for iterating over keys alone the value may be given an ignore-pattern (<code>_</code>).
<
"a" => 1,
"b" => 2,
Line 312 ⟶ 922:
for key in map.domain() { # iterate over the set whose values are the keys
println(`$key .`)
}</
=={{header|EasyLang}}==
<syntaxhighlight lang=text>
# use array of array for this
clothing$[][] = [ [ "type" "t-shirt" ] [ "color" "red" ] [ "size" "xl" ] ]
for i to len clothing$[][]
print clothing$[i][1] & ": " & clothing$[i][2]
.
</syntaxhighlight>
=={{header|EchoLisp}}==
<syntaxhighlight lang="scheme">
(lib 'hash) ;; load hash.lib
(define H (make-hash))
;; fill hash table
(hash-set H 'Simon 42)
(hash-set H 'Albert 666)
(hash-set H 'Antoinette 33)
;; iterate over (key . value ) pairs
(for ([kv H]) (writeln kv))
(Simon . 42)
(Albert . 666)
(Antoinette . 33)
;; iterate over keys
(for ([k (hash-keys H)]) (writeln 'key-> k))
key-> Simon
key-> Albert
key-> Antoinette
;; iterate over values
(for ([v (hash-values H)]) (writeln 'value-> v))
value-> 42
value-> 666
value-> 33
</syntaxhighlight>
=={{header|Elena}}==
ELENA 5.0 :
<syntaxhighlight lang="elena">import system'collections;
import system'routines;
import extensions;
public program()
{
// 1. Create
var map := Dictionary.new();
map["key"] := "foox";
map["key"] := "foo";
map["key2"]:= "foo2";
map["key3"]:= "foo3";
map["key4"]:= "foo4";
// Enumerate
map.forEach:
(keyValue){ console.printLine(keyValue.Key," : ",keyValue.Value) }
}</syntaxhighlight>
=== Strong typed dictionary ===
<syntaxhighlight lang="elena">import system'collections;
import system'routines;
import extensions;
public program()
{
// 1. Create
map["key3"]:= "foo3";
map["key4"]:= "foo4";
// Enumerate
(tuple){ console.printLine(tuple.Item1," : ",tuple.Item2) }
}</syntaxhighlight>
=={{header|Elixir}}==
<syntaxhighlight lang="elixir">IO.inspect d = Map.new([foo: 1, bar: 2, baz: 3])
Enum.each(d, fn kv -> IO.inspect kv end)
Enum.each(d, fn {k,v} -> IO.puts "#{inspect k} => #{v}" end)
Enum.each(Map.keys(d), fn key -> IO.inspect key end)
Enum.each(Map.values(d), fn value -> IO.inspect value end)</syntaxhighlight>
{{out}}
<pre>
%{bar: 2, baz: 3, foo: 1}
{:bar, 2}
{:baz, 3}
{:foo, 1}
:bar => 2
:baz => 3
:foo => 1
:bar
:baz
:foo
2
3
1
</pre>
=={{header|EMal}}==
<syntaxhighlight lang="emal">
Map map = text%text["Italy" => "Rome", "France" => "Paris"]
map.insert("Germany", "Berlin")
map["Spain"] = "Madrid"
writeLine("== pairs ==")
for each Pair pair in map
writeLine(pair)
end
writeLine("== keys ==")
for each text key in map.keys()
writeLine(key)
end
writeLine("== values ==")
for each text value in map.values()
writeLine(value)
end
</syntaxhighlight>
{{out}}
<pre>
== pairs ==
[Italy,Rome]
[France,Paris]
[Germany,Berlin]
[Spain,Madrid]
== keys ==
Italy
France
Germany
Spain
== values ==
Rome
Paris
Berlin
Madrid
</pre>
=={{header|Erlang}}==
<syntaxhighlight lang="erlang">
-module(assoc).
-compile([export_all]).
test_create() ->
D = dict:new(),
D1 = dict:store(foo,1,D),
D2 = dict:store(bar,2,D1),
print_vals(D2).
print_vals(D) ->
lists:foreach(fun (K) ->
io:format("~p: ~b~n",[K,dict:fetch(K,D)])
end, dict:fetch_keys(D)).
</syntaxhighlight>
{{out}}
32> assoc:test_create().
bar: 2
foo: 1
ok
=={{header|F_Sharp|F#}}==
Iterating over both.
<syntaxhighlight lang="fsharp">
let myMap = [ ("Hello", 1); ("World", 2); ("!", 3) ]
for k, v in myMap do
printfn "%s -> %d" k v
</syntaxhighlight>
Iterating over either keys or values only can be achieved through use of the _ wildcard token.
<syntaxhighlight lang="fsharp">
// Only prints the keys.
for k, _ in myMap do
printfn "%s" k
// Only prints the values.
for _, v in myMap do
printfn "%d" v
</syntaxhighlight>
=={{header|Factor}}==
<
<code>assoc-each</code> places both the key and the value on top of the data stack. A simple <code>drop</code> or <code>nip</code> enables iterating over only keys or values.
<syntaxhighlight lang="factor">H{ { "hi" "there" } { "a" "b" } } [ drop print ] assoc-each ! print keys
H{ { "hi" "there" } { "a" "b" } } [ nip print ] assoc-each ! print values</syntaxhighlight>
There's also <code>assoc-map</code>, <code>assoc-find</code>, <code>assoc-filter</code> and many more.
Line 345 ⟶ 1,117:
Given a map, <code>each</code> iterates over pairs of values-keys. <code>keys</code> and <code>vals</code> retrieve a list of keys or values, respectively.
<
class Main
{
Line 368 ⟶ 1,140:
}
}
</syntaxhighlight>
=={{header|Forth}}==
{{libheader|Forth Foundation Library}}
<
include ffl/hci.fs
Line 394 ⟶ 1,166:
;
iterate</
<syntaxhighlight lang="forth">
\ Written in ANS-Forth; tested under VFX.
\ Requires the novice package: http://www.forth.org/novice.html
\ The following should already be done:
\ include novice.4th
\ include association.4th
\ I would define high-level languages as those that allow programs to be written without explicit iteration. Iteration is a major source of bugs.
\ The example from the FFL library doesn't hide iteration, whereas this example from the novice-package does.
marker AssociationIteration.4th
\ ******
\ ****** The following defines a node in an association (each node is derived from ELEMENT).
\ ******
element
w field .inventor
constant language \ describes a programming language
: init-language ( inventor name node -- node )
init-element >r
hstr r@ .inventor !
r> ;
: new-language ( inventor name -- node )
language alloc
init-language ;
: show-language ( count node -- )
>r
1+ \ -- count+1
cr r@ .key @ count colorless type ." invented by: " r@ .inventor @ count type
rdrop ;
: show-languages-forward ( handle -- )
0 \ -- handle count
swap .root @ ['] show-language walk>
cr ." count: " .
cr ;
: show-languages-backward ( handle -- )
0 \ -- handle count
swap .root @ ['] show-language <walk
cr ." count: " .
cr ;
: kill-language-attachments ( node -- )
dup .inventor @ dealloc
kill-key ;
: copy-language-attachments ( src dst -- )
over .inventor @ hstr
over .inventor !
copy-key ;
\ ******
\ ****** The following defines the association itself (the handle).
\ ******
association
constant languages \ describes a set of programming languages
: init-languages ( record -- record )
>r
['] compare ['] kill-language-attachments ['] copy-language-attachments
r> init-association ;
: new-languages ( -- record )
languages alloc
init-languages ;
\ ******
\ ****** The following filters one association into another, including everything that matches a particular inventor.
\ ******
: <filter-inventor> { inventor handle new-handle node -- inventor handle new-handle }
inventor count node .inventor @ count compare A=B = if
node handle dup-element new-handle insert then
inventor handle new-handle ;
: filter-inventor ( inventor handle -- new-handle )
dup similar-association \ -- inventor handle new-handle
over .root @ ['] <filter-inventor> walk> \ -- inventor handle new-handle
nip nip ;
\ ******
\ ****** The following is a demonstration with some sample data.
\ ******
new-languages
c" Moore, Chuck" c" Forth " new-language over insert
c" Ichiah, Jean" c" Ada " new-language over insert
c" Wirth, Niklaus" c" Pascal " new-language over insert
c" Wirth, Niklaus" c" Oberon " new-language over insert
c" McCarthy, John" c" Lisp " new-language over insert
c" van Rossum, Guido" c" Python " new-language over insert
c" Gosling, Jim" c" Java " new-language over insert
c" Ierusalimschy, Roberto" c" Lua " new-language over insert
c" Matsumoto, Yukihiro" c" Ruby " new-language over insert
c" Pestov, Slava" c" Factor " new-language over insert
c" Gosling, James" c" Java " new-language over insert
c" Wirth, Niklaus" c" Modula-2 " new-language over insert
c" Ritchie, Dennis" c" C " new-language over insert
c" Stroustrup, Bjarne" c" C++ " new-language over insert
constant some-languages
cr .( everything in SOME-LANGUAGES ordered forward: )
some-languages show-languages-forward
cr .( everything in SOME-LANGUAGES ordered backward: )
some-languages show-languages-backward
cr .( everything in SOME-LANGUAGES invented by Wirth: )
c" Wirth, Niklaus" some-languages filter-inventor dup show-languages-forward kill-association
cr .( everything in SOME-LANGUAGES within 'F' and 'L': )
c" F" c" L" some-languages filter within dup show-languages-forward kill-association
cr .( everything in SOME-LANGUAGES not within 'F' and 'L': )
c" F" c" L" some-languages filter without dup show-languages-forward kill-association
some-languages kill-association
</syntaxhighlight>
{{out}}
<pre style="height:30ex;overflow:scroll">
everything in SOME-LANGUAGES ordered forward:
Ada invented by: Ichiah, Jean
C invented by: Ritchie, Dennis
C++ invented by: Stroustrup, Bjarne
Factor invented by: Pestov, Slava
Forth invented by: Moore, Chuck
Java invented by: Gosling, James
Lisp invented by: McCarthy, John
Lua invented by: Ierusalimschy, Roberto
Modula-2 invented by: Wirth, Niklaus
Oberon invented by: Wirth, Niklaus
Pascal invented by: Wirth, Niklaus
Python invented by: van Rossum, Guido
Ruby invented by: Matsumoto, Yukihiro
count: 13
everything in SOME-LANGUAGES ordered backward:
Ruby invented by: Matsumoto, Yukihiro
Python invented by: van Rossum, Guido
Pascal invented by: Wirth, Niklaus
Oberon invented by: Wirth, Niklaus
Modula-2 invented by: Wirth, Niklaus
Lua invented by: Ierusalimschy, Roberto
Lisp invented by: McCarthy, John
Java invented by: Gosling, James
Forth invented by: Moore, Chuck
Factor invented by: Pestov, Slava
C++ invented by: Stroustrup, Bjarne
C invented by: Ritchie, Dennis
Ada invented by: Ichiah, Jean
count: 13
everything in SOME-LANGUAGES invented by Wirth:
Modula-2 invented by: Wirth, Niklaus
Oberon invented by: Wirth, Niklaus
Pascal invented by: Wirth, Niklaus
count: 3
everything in SOME-LANGUAGES within 'F' and 'L':
Factor invented by: Pestov, Slava
Forth invented by: Moore, Chuck
Java invented by: Gosling, James
count: 3
everything in SOME-LANGUAGES not within 'F' and 'L':
Ada invented by: Ichiah, Jean
C invented by: Ritchie, Dennis
C++ invented by: Stroustrup, Bjarne
Lisp invented by: McCarthy, John
Lua invented by: Ierusalimschy, Roberto
Modula-2 invented by: Wirth, Niklaus
Oberon invented by: Wirth, Niklaus
Pascal invented by: Wirth, Niklaus
Python invented by: van Rossum, Guido
Ruby invented by: Matsumoto, Yukihiro
count: 10
</pre>
=={{header|FreeBASIC}}==
Use the typedefs and data from [[Associative Array/Creation#FreeBASIC]] as an include.
Since this data structure stores the keys and values together it makes little sense to iterate through the same array three times to print different parts of it, hence I will only print the key:value pairs.
<syntaxhighlight lang="freebasic">#include"assoc.bas"
function get_dict_data_string( d as dicitem ) as string
select case d.datatype
case BOOL
if d.value.bool then return "true" else return "false"
case INTEG
return str(d.value.integ)
case STRNG
return """"+d.value.strng+""""
case FLOAT
return str(d.value.float)
case BYYTE
return str(d.value.byyte)
case else
return "DATATYPE ERROR"
end select
end function
sub print_keyval_pair( d as dicentry )
print using "{&} : {&}";get_dict_data_string( d.key ); get_dict_data_string(d.value)
end sub
for i as uinteger = 0 to ubound(Dictionary)
print_keyval_pair(Dictionary(i))
next i</syntaxhighlight>
{{out}}
<pre>
{"Cat"} : {"Mittens"}
{32767} : {2.718281828}
</pre>
=={{header|Free Pascal}}==
FPC 3.2.0+. Similar to Delphi:<syntaxhighlight lang="pascal">program AssociativeArrayIteration;
{$mode delphi}{$ifdef windows}{$apptype console}{$endif}
uses Generics.Collections;
type
TlDictionary = TDictionary<string, Integer>;
TlPair = TPair<string,integer>;
var
i: Integer;
s: string;
lDictionary: TlDictionary;
lPair: TlPair;
begin
lDictionary := TlDictionary.Create;
try
lDictionary.Add('foo', 5);
lDictionary.Add('bar', 10);
lDictionary.Add('baz', 15);
lDictionary.AddOrSetValue('foo',6);
for lPair in lDictionary do
Writeln('Pair: ',Lpair.Key,' = ',lPair.Value);
for s in lDictionary.Keys do
Writeln('Key: ' + s);
for i in lDictionary.Values do
Writeln('Value: ', i);
finally
lDictionary.Free;
end;
end.</syntaxhighlight>
<pre>
Pair: foo = 6
Pair: bar = 10
Pair: baz = 15
Key: foo
Key: bar
Key: baz
Value: 6
Value: 10
Value: 15</pre>
=={{header|Frink}}==
<syntaxhighlight lang="frink">d = new dict[[[1, "one"], [2, "two"]]]
for [key, value] = d
println["$key\t$value"]
println[]
for key = keys[d]
println["$key"]
</syntaxhighlight>
{{out}}
<pre>
2 two
1 one
2
1
</pre>
=={{header|FutureBasic}}==
There are many ways to iterate over an associative array (dictionary) in FutureBasic. Below are a selection.
1. for ... in ...
<syntaxhighlight lang="futurebasic">
void local fn DoIt
CFDictionaryRef dict = @{@"A":@"Alpha", @"B":@"Bravo", @"C":@"Charlie", @"D":@"Delta"}
CFStringRef key
for key in dict
print key, dict[key]
next
end fn
fn DoIt
HandleEvents
</syntaxhighlight>
2. Enumerator callback
<syntaxhighlight lang="futurebasic">
void local fn MyDictEnumerator( dict as CFDictionaryRef, key as CFTypeRef, obj as CFTypeRef, stp as ^BOOL, userData as ptr )
print key, obj
end fn
void local fn DoIt
CFDictionaryRef dict = @{@"A":@"Alpha", @"B":@"Bravo", @"C":@"Charlie", @"D":@"Delta"}
DictionaryEnumerateKeysAndObjects( dict, @fn MyDictEnumerator, NULL )
end fn
fn DoIt
HandleEvents
</syntaxhighlight>
3. Array of keys
<syntaxhighlight lang="futurebasic">
void local fn DoIt
CFDictionaryRef dict = @{@"A":@"Alpha", @"B":@"Bravo", @"C":@"Charlie", @"D":@"Delta"}
CFArrayRef keys = fn DictionaryAllKeys( dict )
CFStringRef key
for key in keys
print key, dict[key]
next
end fn
fn DoIt
HandleEvents
</syntaxhighlight>
4. Array of values
<syntaxhighlight lang="futurebasic">
void local fn DoIt
CFDictionaryRef dict = @{@"A":@"Alpha", @"B":@"Bravo", @"C":@"Charlie", @"D":@"Delta"}
CFArrayRef values = fn DictionaryAllValues( dict )
CFStringRef value
for value in values
print value
next
end fn
fn DoIt
HandleEvents
</syntaxhighlight>
5. Key/object enumerators
<syntaxhighlight lang="futurebasic">
void local fn DoIt
CFDictionaryRef dict = @{@"A":@"Alpha", @"B":@"Bravo", @"C":@"Charlie", @"D":@"Delta"}
CFStringRef key
CFTypeRef obj
EnumeratorRef keyEnumerator = fn DictionaryKeyEnumerator( dict )
key = fn EnumeratorNextObject( keyEnumerator )
while ( key )
print key,dict[key]
key = fn EnumeratorNextObject( keyEnumerator )
wend
print
EnumeratorRef objectEnumerator = fn DictionaryObjectEnumerator( dict )
obj = fn EnumeratorNextObject( objectEnumerator )
while ( obj )
print obj
obj = fn EnumeratorNextObject( objectEnumerator )
wend
end fn
fn DoIt
HandleEvents
</syntaxhighlight>
=={{header|Gambas}}==
'''[https://gambas-playground.proko.eu/?gist=e48bd6ed7e6b583106b8178bca536eea Click this link to run this code]'''
<syntaxhighlight lang="gambas">Public Sub Main()
Dim cList As Collection = ["2": "quick", "4": "fox", "1": "The", "9": "dog", "7": "the", "5": "jumped", "3": "brown", "6": "over", "8": "lazy"]
Dim siCount As Short
Dim sTemp As String
For Each sTemp In cList
Print cList.key & "=" & sTemp;;
Next
Print
For siCount = 1 To cList.Count
Print cList[Str(siCount)];;
Next
End</syntaxhighlight>
Output:
<pre>
2=quick 4=fox 1=The 9=dog 7=the 5=jumped 3=brown 6=over 8=lazy
The quick brown fox jumped over the lazy dog
</pre>
=={{header|Go}}==
'''Language:'''
<syntaxhighlight lang="go">myMap := map[string]int {
"hello": 13,
"world": 31,
Line 422 ⟶ 1,610:
for _, value := range myMap {
fmt.Printf("value = %d\n", value)
}</
'''Standard library templates:'''
In addition to the for/range features of the language, the text/template and html/template packages of the standard library have map iteration features. Some differences worth noting:
* A single assigned value in a template is the map value. With the language for/range it is the key.
* Templates have no equivalent of _; a dummy variable must be used.
* In a template, if map keys are a comparable basic type, then iteration proceeds in key order. With the language for/range, iteration is in non-deterministic order.
<syntaxhighlight lang="go">package main
import (
"os"
"text/template"
)
func main() {
m := map[string]int{
"hello": 13,
"world": 31,
"!": 71,
}
// iterating over key-value pairs:
template.Must(template.New("").Parse(`
{{- range $k, $v := . -}}
key = {{$k}}, value = {{$v}}
{{end -}}
`)).Execute(os.Stdout, m)
// iterating over keys:
template.Must(template.New("").Parse(`
{{- range $k, $v := . -}}
key = {{$k}}
{{end -}}
`)).Execute(os.Stdout, m)
// iterating over values:
template.Must(template.New("").Parse(`
{{- range . -}}
value = {{.}}
{{end -}}
`)).Execute(os.Stdout, m)
}</syntaxhighlight>
{{out}}
Note order by key.
<pre>
key = !, value = 71
key = hello, value = 13
key = world, value = 31
key = !
key = hello
key = world
value = 71
value = 13
value = 31
</pre>
=={{header|Groovy}}==
Solution:
<
println "Entries:"
Line 437 ⟶ 1,680:
println()
println "Values:"
map.values().each { println it }</
{{out}}
<pre>Entries:
lastName=Anderson
Line 460 ⟶ 1,703:
24
everywhere</pre>
=={{header|Harbour}}==
<syntaxhighlight lang="visualfoxpro">LOCAL arr := { 6 => 16, "eight" => 8, "eleven" => 11 }
LOCAL x
FOR EACH x IN arr
// key, value
? x:__enumKey(), x
// or key only
? x:__enumKey()
// or value only
? x
NEXT</syntaxhighlight>
=={{header|Haskell}}==
with Data.Map:
<
myMap :: M.Map String Int
myMap = M.fromList [("hello", 13), ("world", 31), ("!", 71)]
main
main =
(putStrLn . unlines) $
[ show . M.toList
, show . M.keys --
, show . M.elems
] <*>
pure myMap</syntaxhighlight>
{{Out}}
<pre>[("!",71),("hello",13),("world",31)]
["!","hello","world"]
[71,13,31]</pre>
=={{header|Icon}} and {{header|Unicon}}==
<
t := table()
every t[a := !"ABCDE"] := map(a)
Line 489 ⟶ 1,752:
every writes(" ",!t)
write()
end</
{{out}}
<pre>->aai
A -> a
Line 500 ⟶ 1,763:
Keys: C E B D A
Values: c e b d a</pre>
=={{header|Io}}==
<syntaxhighlight lang="io">myDict := Map with(
"hello", 13,
"world", 31,
"!" , 71
)
// iterating over key-value pairs:
myDict foreach( key, value,
writeln("key = ", key, ", value = ", value)
)
// iterating over keys:
myDict keys foreach( key,
writeln("key = ", key)
)
// iterating over values:
myDict foreach( value,
writeln("value = ", value)
)
// or alternatively:
myDict values foreach( value,
writeln("value = ", value)
)</syntaxhighlight>
=={{header|J}}==
Line 507 ⟶ 1,796:
Using the J example from [[Creating an Associative Array]]...
Keys <syntaxhighlight lang
Values <syntaxhighlight lang
Both keys and values <
Note that this last is not likely to be useful in any practical context outside of learning the language.
=={{header|Jakt}}==
<syntaxhighlight lang="jakt">
fn main() {
let dictionary = ["foo": 1, "bar": 2]
for entry in dictionary {
// To get values, use
// let value = entry.1
println("{}", entry)
}
// Just keys
for key in dictionary.keys() {
println("{}", key)
}
}
</syntaxhighlight>
{{out}}
<pre>
("bar", 2)
("foo", 1)
bar
foo
</pre>
=={{header|Java}}==
<p>
See also, [https://rosettacode.org/wiki/Associative_array/Creation#Java Java - Associative array/Creation].
</p>
<p>
You can access the <kbd>key</kbd> and <kbd>value</kbd> pairs by using the <code>Map.entrySet</code> method,
which will return a <code>Map.Entry</code>.<br />
It's worth noting that a <code>Map.Entry</code> also has the <code>setValue</code> method.
</p>
<syntaxhighlight lang="java">
for (Map.Entry<String, Integer> entry : map.entrySet())
System.out.println(entry);
</syntaxhighlight>
<p>
You can access just the <kbd>key</kbd>s by using the <code>Map.keySet</code> method, which will return a <code>Set</code>.
</p>
<syntaxhighlight lang="java">
for (String key : map.keySet())
System.out.println(key);
</syntaxhighlight>
<p>
And you can access just the <kbd>value</kbd>s by using the <code>Map.values</code> method, which will return a <code>Collection</code>.
</p>
<syntaxhighlight lang="java">
for (int value : map.values())
System.out.println(value);
</syntaxhighlight>
<br />
Java 8 version
<syntaxhighlight lang="java">Map<String, Integer> map = new HashMap<>();
map.put("hello", 1);
map.put("world", 2);
map.put("!", 3);
// iterating over key-value pairs:
map.forEach((k, v) -> {
});
// iterating over keys:
map.keySet().forEach(k -> System.out.printf("key = %s%n", k));
// iterating over values:
map.values().forEach(v -> System.out.printf("value = %s%n", v));</syntaxhighlight>
{{out}}
<pre>key = !, value = 3
key = world, value = 2
key = hello, value = 1
key = !
key = world
key = hello
value = 3
value = 2
value = 1</pre>
=={{header|JavaScript}}==
JavaScript does not have associative arrays until ECMAScript 6 brings Maps.
<
myhash["hello"] = 3;
myhash.world = 6;
myhash["!"] = 9;
//iterate using for..in loop
for (var key in myhash) {
//ensure key is in object and not in prototype
console.log("Key is: " +
}
}
//iterate using ES5.1 Object.keys() and Array.prototype.Map()
var keys = Object.keys(); //get Array of object keys (doesn't get prototype keys)
keys.map(function (key) {
console.log("Key is: " + key + '. Value is: ' + myhash[key]);
});</syntaxhighlight>
=={{header|Jq}}==
In jq, there are several ways to iterate over compound structures:
- functionally, e.g. using map on an array
- by enumeration, i.e. by generating a stream
- by performing a reduction
For the sake of brevity, therefore, in the following we will only illustrate the enumerative approach.
With respect to associative arrays (i.e. JSON objects), the fundamental functions are:
- keys -- for producing an array of the keys (sorted)
- .[] -- for producing a stream of the values
In jq > 1.4, keys_unsorted, for producing an array of the keys (in the order of creation), is also available.
<syntaxhighlight lang="jq">def mydict: {"hello":13, "world": 31, "!": 71};
# Iterating over the keys
mydict | keys[]
# "!"
# "hello"
# "world"
# Iterating over the values:
mydict[]
# 13
# 31
# 71
# Generating a stream of {"key": key, "value": value} objects:
mydict | to_entries[]
# {"key":"hello","value":13}
# {"key":"world","value":31}
# {"key":"!","value":71}
# Generating a stream of [key,value] arrays:
mydict | . as $o | keys[] | [., $o[.]]
#["!",71]
#["hello",13]
#["world",31]
# Generating a stream of [key,value] arrays, without sorting (jq > 1.4 required)
mydict | . as $o | keys_unsorted[] | [., $o[.]]
# ["hello",13]
# ["world",31]
# ["!",71]
</syntaxhighlight>
=={{header|Julia}}==
{{works with|Julia|0.6}}
<syntaxhighlight lang="julia">dict = Dict("hello" => 13, "world" => 31, "!" => 71)
# applying a function to key-value pairs:
foreach(println, dict)
# iterating over key-value pairs:
for (key, value) in dict
println("dict[$key] = $value")
end
# iterating over keys:
for key in keys(dict)
@show key
end
# iterating over values:
for value in values(dict)
@show value
end
</syntaxhighlight>
{{out}}
<pre>
key = !, value = 71
key = hello, value = 13
key = world, value = 31
key = !
key = hello
key = world
value = 71
value = 13
value = 31
</pre>
=={{header|K}}==
Creating a dictionary.
<
The keys are available via "!".
<
`hello `world `"!"
Line 582 ⟶ 2,000:
("hello"
"world"
,"!")</
Print the key value pairs.
<
hello: 1
world: 2
!: 3</
The values are available via "[]".
<
1 2 3
{x+1}'d[]
2 3 4</
=={{header|Kotlin}}==
<syntaxhighlight lang="scala">fun main() {
val map = mapOf("hello" to 1, "world" to 2, "!" to 3)
with(map) {
forEach { println("key = ${it.key}, value = ${it.value}") }
keys.forEach { println("key = $it") }
values.forEach { println("value = $it") }
}
}</syntaxhighlight>
{{Out}}
<pre>key = hello, value = 1
key = world, value = 2
key = !, value = 3
key = hello
key = world
key = !
value = 1
value = 2
value = 3</pre>
=={{header|Lang5}}==
<syntaxhighlight lang="lang5">: first 0 extract nip ; : second 1 extract nip ; : nip swap drop ;
: say(*) dup first " => " 2 compress "" join . second . ;
[['foo 5] ['bar 10] ['baz 20]] 'say apply drop</syntaxhighlight>
=={{header|Lasso}}==
<syntaxhighlight lang="lasso">
//iterate over associative array
//Lasso maps
local('aMap' = map('weight' = 112,
'height' = 45,
'name' = 'jason'))
' Map output: \n '
#aMap->forEachPair => {^
//display pair, then show accessing key and value individually
#1+'\n '
#1->first+': '+#1->second+'\n '
^}
//display keys and values separately
'\n'
' Map Keys: '+#aMap->keys->join(',')+'\n'
' Map values: '+#aMap->values->join(',')+'\n'
//display using forEach
'\n'
' Use ForEach to iterate Map keys: \n'
#aMap->keys->forEach => {^
#1+'\n'
^}
'\n'
' Use ForEach to iterate Map values: \n'
#aMap->values->forEach => {^
#1+'\n'
^}
//the {^ ^} indicates that output should be printed (AutoCollect) ,
// if output is not desired, just { } is used
</syntaxhighlight>
=={{header|LFE}}==
===Keys and Values===
<syntaxhighlight lang="lisp">
(let ((data '(#(key1 "foo") #(key2 "bar")))
(hash (: dict from_list data)))
(: dict fold
(lambda (key val accum)
(: io format '"~s: ~s~n" (list key val)))
0
hash))
</syntaxhighlight>
===Just Keys===
<syntaxhighlight lang="lisp">
(let ((data '(#(key1 "foo") #(key2 "bar")))
(hash (: dict from_list data)))
(: lists map
(lambda (key)
(: io format '"~s~n" (list key)))
(: dict fetch_keys hash)))
</syntaxhighlight>
=={{header|Liberty BASIC}}==
Needs the sublist library from http://basic.wikispaces.com/SubList+Library since LB does not have built-in associative arrays.
<syntaxhighlight lang="lb">
data "red", "255 50 50", "green", "50 255 50", "blue", "50 50 255"
data "my fave", "220 120 120", "black", "0 0 0"
Line 623 ⟶ 2,124:
end
</syntaxhighlight>
Number of key-data pairs =5
Key 1: red Data: 255 50 50
Line 630 ⟶ 2,131:
Key 4: my fave Data: 220 120 120
Key 5: black Data: 0 0 0
=={{header|Lingo}}==
<syntaxhighlight lang="lingo">hash = [#key1:"value1", #key2:"value2", #key3:"value3"]
-- iterate over key-value pairs
repeat with i = 1 to hash.count
put hash.getPropAt(i) & "=" & hash[i]
end repeat
-- iterating over values only can be written shorter
repeat with val in hash
put val
end repeat</syntaxhighlight>
=={{header|LiveCode}}==
<syntaxhighlight lang="livecode">put 3 into fruit["apples"]
put 5 into fruit["pears"]
put 6 into fruit["oranges"]
put "none" into fruit["bananas"]
put "Keys:" & cr & the keys of fruit & cr into tTmp
put "Values 1:" & tab after tTmp
repeat for each line tKey in the keys of fruit
put fruit[tkey] & comma after tTmp
end repeat
-- need to copy array as combine will change variable
put fruit into fruit2
combine fruit2 using comma
put cr & "Values2:" & tab after tTmp
repeat for each item f2val in fruit2
put f2val & comma after tTmp
end repeat
combine fruit using return and ":"
put cr & "Key:Values" & cr & fruit after tTmp
-- alternatively, use same loop as for values 1 with tkey && fruit[tKey]
put tTmp</syntaxhighlight>
Output
<syntaxhighlight lang="livecode">Keys:
apples
pears
oranges
bananas
Values 1: 3,5,6,none,
Values2: 3,none,6,5,
Key:Values
apples:3
bananas:none
oranges:6
pears:5</syntaxhighlight>
=={{header|Lua}}==
<
["foo"] = "bar",
["baz"] = 6,
}
for key,val in pairs(t) do
print(string.format("%s: %s", key, val))
end</syntaxhighlight>
{{out}}
<pre>
fortytwo: 7
foo: bar
baz: 6
</pre>
''Note:'' the order in which <code>pairs</code> iterates over non-integer keys is not defined, so the order of lines in the output of the above code may differ from one run to another.
=={{header|M2000 Interpreter}}==
<syntaxhighlight lang="m2000 interpreter">
Module checkit {
\\ Inventories are objects with keys and values, or keys (used as read only values)
\\ They use hash function.
\\ Function TwoKeys return Inventory object (as a pointer to object)
Function TwoKeys {
Inventory Alfa="key1":=100, "key2":=200
=Alfa
}
M=TwoKeys()
Print Type$(M)="Inventory"
\\ Normal Use:
\\ Inventories Keys are case sensitive
\\ M2000 identifiers are not case sensitive
Print M("key1"), m("key2")
\\ numeric values can convert to strings
Print M$("key1"), m$("key2")
\\ Iteration
N=Each(M)
While N {
Print Eval(N) ' prints 100, 200 as number
Print M(N^!) ' The same using index N^
}
N=Each(M)
While N {
Print Eval$(N) ' prints 100, 200 as strings
Print M$(N^!) ' The same using index N^
}
N=Each(M)
While N {
Print Eval$(N, N^) ' Prints Keys
}
\\ double iteration
Append M, "key3":=500
N=Each(M, 1, -1) ' start to end
N1=Each(M, -1, 1) ' end to start
\\ 3x3 prints
While N {
While N1 {
Print format$("{0}*{1}={2}", Eval(N1), Eval(N), Eval(N1)*Eval(N))
}
}
\\ sort results from lower product to greater product (3+2+1, 6 prints only)
N=Each(M, 1, -1)
While N {
N1=Each(M, N^+1, -1)
While N1 {
Print format$("{0}*{1}={2}", Eval(N1), Eval(N), Eval(N1)*Eval(N))
}
}
N=Each(M)
N1=Each(M,-2, 1) ' from second from end to start
\\ print only 2 values. While block ends when one iterator finish
While N, N1 {
Print Eval(N1)*Eval(N)
}
}
Checkit
</syntaxhighlight>
=={{header|M4}}==
<
define(`for',
`ifelse($#,0,``$0'',
Line 676 ⟶ 2,299:
for(`x',1,asize(`a'),
`avalue(`a',x)
')</
{{out}}
<pre>
key-value pairs
Line 692 ⟶ 2,315:
`7'
</pre>
=={{header|Maple}}==
Iterate through indices when indices are all simple expressions:
<syntaxhighlight lang="maple">
> T := table( [ "A" = 1, "B" = 2, "C" = 3, "D" = 4 ] );
> for i in indices( T, nolist ) do print(i ) end:
"A"
"B"
"C"
"D"
</syntaxhighlight>
Iterate through indices when indices may be expression sequences:
<syntaxhighlight lang="maple">
> T := table( [ "a" = 1, "b" = 2, ("c","d") = 3 ] ):
> for i in indices( T ) do print( i, T[ op( i ) ] ) end:
["a"], 1
["b"], 2
["c", "d"], 3
</syntaxhighlight>
Return all index / entry pairs as equations:
<syntaxhighlight lang="maple">
> for i in indices( T, pairs ) do print( i) end:
"a" = 1
"b" = 2
("c", "d") = 3
</syntaxhighlight>
<syntaxhighlight lang="maple">
> for i in entries( T ) do print( i) end:
[1]
[3]
[2]
</syntaxhighlight>
=={{header|Mathematica}} / {{header|Wolfram Language}}==
<syntaxhighlight lang="mathematica">keys=DownValues[#,Sort->False][[All,1,1,1]]&;
hashes=#/@keys[#]&;
a[2]="string";a["sometext"]=23;
keys[a]
->{2,sometext}
hashes[a]
->{string,23}</syntaxhighlight>
=={{header|MATLAB}} / {{header|Octave}}==
Associative arrays can be defined as structs in Matlab and Octave.
<syntaxhighlight lang="matlab"> keys = fieldnames(hash);
for k=1:length(keys),
key = keys{k};
value = getfield(hash,key); % get value of key
hash = setfield(hash,key,-value); % set value of key
end; </syntaxhighlight>
or
<syntaxhighlight lang="matlab"> keys = fieldnames(hash);
for k=1:length(keys),
key = keys{k};
value = hash.(key); % get value of key
hash.(key) = -value; % set value of key
end; </syntaxhighlight>
=={{header|Maxima}}==
<syntaxhighlight lang="maxima">h[1]: 6$
h[9]: 2$
/* iterate over values */
for val in listarray(h) do (
print(val))$
/* iterate over the keys */
for key in rest(arrayinfo(h), 2) do (
val: arrayapply(h, key),
print(key, val))$</syntaxhighlight>
=={{header|MiniScript}}==
<syntaxhighlight lang="miniscript">d = { 3: "test", "foo": 3 }
for keyVal in d
print keyVal // produces results like: { "key": 3, "value": "test" }
end for
for key in d.indexes
print key
end for
for val in d.values
print val
end for</syntaxhighlight>
=={{header|NetRexx}}==
<
options replace format comments java crossref
surname = 'Unknown' -- default value
Line 707 ⟶ 2,432:
loop fn over surname
say fn.right(10) ':' surname[fn]
end fn</syntaxhighlight>
=={{header|NewLISP}}==
<syntaxhighlight lang="newlisp">;; using an association list:
(setq alist '(("A" "a") ("B" "b") ("C" "c")))
;; list keys
(map first alist)
;; list values
(map last alist)
;; loop over the assocation list:
(dolist (elem alist)
(println (format "%s -> %s" (first elem) (last elem))))</syntaxhighlight>
=={{header|Nim}}==
<syntaxhighlight lang="nim">
import tables
var t: Table[int,string]
t[1] = "one"
t[2] = "two"
t[3] = "three"
t[4] = "four"
echo "t has " & $t.len & " elements"
echo "has t key 4? " & $t.hasKey(4)
echo "has t key 5? " & $t.hasKey(5)
#iterate keys
echo "key iteration:"
for k in t.keys:
echo "at[" & $k & "]=" & t[k]
#iterate pairs
echo "pair iteration:"
for k,v in t.pairs:
echo "at[" & $k & "]=" & v
</syntaxhighlight>
{{out}}
<pre>
t has 4 elements
has t key 4? true
has t key 5? false
key iteration:
at[1]=one
at[2]=two
at[3]=three
at[4]=four
pair iteration:
at[1]=one
at[2]=two
at[3]=three
at[4]=four
</pre>
=={{header|Oberon-2}}==
{{works with|OO2C|Version 2}}
<syntaxhighlight lang="modula2">
MODULE AssociativeArray;
IMPORT
ADT:Dictionary,
Object:Boxed,
Out;
TYPE
Key = STRING;
Value = Boxed.LongInt;
VAR
assocArray: Dictionary.Dictionary(Key,Value);
iterK: Dictionary.IterKeys(Key,Value);
iterV: Dictionary.IterValues(Key,Value);
aux: Value;
k: Key;
BEGIN
assocArray := NEW(Dictionary.Dictionary(Key,Value));
assocArray.Set("ten",NEW(Value,10));
assocArray.Set("eleven",NEW(Value,11));
aux := assocArray.Get("ten");
Out.LongInt(aux.value,0);Out.Ln;
aux := assocArray.Get("eleven");
Out.LongInt(aux.value,0);Out.Ln;Out.Ln;
(* Iterate keys *)
iterK := assocArray.IterKeys();
WHILE (iterK.Next(k)) DO
Out.Object(k);Out.Ln
END;
Out.Ln;
(* Iterate values *)
iterV := assocArray.IterValues();
WHILE (iterV.Next(aux)) DO
Out.LongInt(aux.value,0);Out.Ln
END
END AssociativeArray.
</syntaxhighlight>
=={{header|Objeck}}==
<syntaxhighlight lang="objeck">
class Iteration {
function : Main(args : String[]) ~ Nil {
assoc_array := Collection.StringMap->New();
assoc_array->Insert("Hello", IntHolder->New(1));
assoc_array->Insert("World", IntHolder->New(2));
assoc_array->Insert("!", IntHolder->New(3));
keys := assoc_array->GetKeys();
values := assoc_array->GetValues();
each(i : keys) {
key := keys->Get(i)->As(String);
value := assoc_array->Find(key)->As(IntHolder)->Get();
"key={$key}, value={$value}"->PrintLine();
};
"-------------"->PrintLine();
each(i : keys) {
key := keys->Get(i)->As(String);
value := values->Get(i)->As(IntHolder)->Get();
"key={$key}, value={$value}"->PrintLine();
};
}
}
</syntaxhighlight>
=={{header|Objective-C}}==
{{works with|Objective-C|2.0+}}
<
[NSNumber numberWithInt:13], @"hello",
[NSNumber numberWithInt:31], @"world",
Line 725 ⟶ 2,581:
for (id value in [myDict objectEnumerator]) {
NSLog(@"value = %@", value);
}</
{{works with|Objective-C|<2.0}}
<
[NSNumber numberWithInt:13], @"hello",
[NSNumber numberWithInt:31], @"world",
Line 745 ⟶ 2,601:
while ((value = [enm nextObject])) {
NSLog(@"value = %@", value);
}</
{{works with|Cocoa|Mac OS X 10.6+}}
<
[NSNumber numberWithInt:13], @"hello",
[NSNumber numberWithInt:31], @"world",
Line 756 ⟶ 2,612:
[myDict enumerateKeysAndObjectsUsingBlock: ^(id key, id value, BOOL *stop) {
NSLog(@"key = %@, value = %@", key, value);
}];</
=={{header|OCaml}}==
Association
<
let map = [| ('A', 1); ('B', 2); ('C', 3) |] ;;
Line 774 ⟶ 2,630:
(* in functional programming it is often more useful to fold over the elements *)
Array.fold_left (fun acc (k,v) -> acc ^ Printf.sprintf "key: %c - value: %d\n" k v) "Elements:\n" map ;;</
Hash table:
<
Hashtbl.add map 'A' 1;;
Hashtbl.add map 'B' 2;;
Line 786 ⟶ 2,642:
(* in functional programming it is often more useful to fold over the elements *)
Hashtbl.fold (fun k v acc -> acc ^ Printf.sprintf "key: %c - value: %d\n" k v) map "Elements:\n" ;;</
Functional binary search tree:
<
let map = CharMap.empty;;
let map = CharMap.add 'A' 1 map;;
Line 799 ⟶ 2,655:
(* in functional programming it is often more useful to fold over the elements *)
CharMap.fold (fun k v acc -> acc ^ Printf.sprintf "key: %c - value: %d\n" k v) map "Elements:\n" ;;</
=={{header|Ol}}==
<syntaxhighlight lang="ol">
;;; create sample associative array
(define aa (list->ff '(
(hello . 1)
(world . 2)
(! . 3))))
(print aa)
; ==> #((! . 3) (hello . 1) (world . 2))
;;; simplest iteration over all associative array (using ff-iter, lazy iterator)
(let loop ((kv (ff-iter aa)))
(cond
((null? kv) #true)
((pair? kv)
(print (car kv))
(loop (cdr kv)))
(else (loop (force kv)))))
; ==> (! . 3)
; ==> (hello . 1)
; ==> (world . 2)
;;; iteration with returning value (using ff-fold)
(print
"folding result: "
(ff-fold
(lambda (result key value)
(print "key: " key ", value: " value)
(+ result 1))
0
aa))
; ==> key: !, value: 3
; ==> key: hello, value: 1
; ==> key: world, value: 2
; ==> folding result: 3
;;; same but right fold (using ff-foldr)
(print
"rfolding result: "
(ff-foldr
(lambda (result key value)
(print "key: " key ", value: " value)
(+ result 1))
0
aa))
; ==> key: world, value: 2
; ==> key: hello, value: 1
; ==> key: !, value: 3
; ==> rfolding result: 3
;;; at least create new array from existing (let's multiply every value by value)
(define bb (ff-map aa
(lambda (key value)
(* value value))))
(print bb)
; ==> #((! . 9) (hello . 1) (world . 4))
</syntaxhighlight>
=={{header|ooRexx}}==
<syntaxhighlight lang="oorexx">d = .directory~new
d["hello"] = 1
d["world"] = 2
d["!"] = 3
-- iterating over keys:
loop key over d
say "key =" key
end
-- iterating over values:
loop value over d~allitems
say "value =" value
end
-- iterating over key-value pairs:
s = d~supplier
loop while s~available
say "key =" s~index", value =" s~item
s~next
end</syntaxhighlight>
{{out}}
<pre>key = !
key = world
key = hello
value = 3
value = 2
value = 1
key = !, value = 3
key = world, value = 2
key = hello, value = 1</pre>
=={{header|Oz}}==
<
MyMap = unit('hello':13 'world':31 '!':71)
in
{ForAll {Record.toListInd MyMap} Show} %% pairs
{ForAll {Record.arity MyMap} Show} %% keys
{ForAll {Record.toList MyMap} Show} %% values</
=={{header|PARI/GP}}==
{{works with|PARI/GP|2.8.1+}}
The keys can be retried from a map with Vec:
<syntaxhighlight lang="parigp">keys = Vec(M);</syntaxhighlight>
You can iterate over the values as usual:
<syntaxhighlight lang="parigp">for(i=1,#keys,
print(keys[i]," ",mapget(M,keys[i]))
)</syntaxhighlight>
=={{header|PascalABC.NET}}==
<syntaxhighlight lang="delphi">
begin
var zoo := new Dictionary<string,integer>;
zoo['crocodile'] := 2;
zoo['jiraffe'] := 3;
zoo['behemoth'] := 1;
foreach var kv in zoo do
Println(kv.Key, kv.Value);
Println;
foreach var key in zoo.Keys do
Println(key,zoo[key]);
end.
</syntaxhighlight>
{{out}}
<pre>
crocodile 2
jiraffe 3
behemoth 1
crocodile 2
jiraffe 3
behemoth 1
</pre>
=={{header|Perl}}==
<
use strict;
Line 841 ⟶ 2,830:
foreach my $val ( values %pairs ) {
print "value = $val\n";
}</
=={{header|
The first three lines create a simple dictionary, with keys and values of several different types (string/integer/sequence):
<!--<syntaxhighlight lang="phix">(phixonline)-->
<span style="color: #008080;">with</span> <span style="color: #008080;">javascript_semantics</span>
<span style="color: #7060A8;">setd</span><span style="color: #0000FF;">(</span><span style="color: #008000;">"one"</span><span style="color: #0000FF;">,</span><span style="color: #000000;">1</span><span style="color: #0000FF;">)</span>
<span style="color: #7060A8;">setd</span><span style="color: #0000FF;">(</span><span style="color: #000000;">2</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"duo"</span><span style="color: #0000FF;">)</span>
<span style="color: #7060A8;">setd</span><span style="color: #0000FF;">({</span><span style="color: #000000;">3</span><span style="color: #0000FF;">,</span><span style="color: #000000;">4</span><span style="color: #0000FF;">},{</span><span style="color: #000000;">5</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"six"</span><span style="color: #0000FF;">})</span>
<span style="color: #008080;">function</span> <span style="color: #000000;">visitor</span><span style="color: #0000FF;">(</span><span style="color: #004080;">object</span> <span style="color: #000000;">key</span><span style="color: #0000FF;">,</span> <span style="color: #004080;">object</span> <span style="color: #000000;">data</span><span style="color: #0000FF;">,</span> <span style="color: #004080;">object</span> <span style="color: #000080;font-style:italic;">/*userdata*/</span><span style="color: #0000FF;">)</span>
<span style="color: #0000FF;">?{</span><span style="color: #000000;">key</span><span style="color: #0000FF;">,</span><span style="color: #000000;">data</span><span style="color: #0000FF;">}</span>
<span style="color: #008080;">return</span> <span style="color: #000000;">1</span> <span style="color: #000080;font-style:italic;">-- (continue traversal)</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">function</span>
<span style="color: #7060A8;">traverse_dict</span><span style="color: #0000FF;">(</span><span style="color: #7060A8;">routine_id</span><span style="color: #0000FF;">(</span><span style="color: #008000;">"visitor"</span><span style="color: #0000FF;">))</span>
<!--</syntaxhighlight>-->
{{out}}
<pre>
{2,"duo"}
{{3,4},{5,"six"}}
{"one",1}
</pre>
You could also use some of the map.e routines:
<!--<syntaxhighlight lang="phix">(phixonline)-->
<span style="color: #008080;">with</span> <span style="color: #008080;">javascript_semantics</span>
<span style="color: #7060A8;">setd</span><span style="color: #0000FF;">(</span><span style="color: #008000;">"one"</span><span style="color: #0000FF;">,</span><span style="color: #000000;">1</span><span style="color: #0000FF;">)</span>
<span style="color: #7060A8;">setd</span><span style="color: #0000FF;">(</span><span style="color: #000000;">2</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"duo"</span><span style="color: #0000FF;">)</span>
<span style="color: #7060A8;">setd</span><span style="color: #0000FF;">({</span><span style="color: #000000;">3</span><span style="color: #0000FF;">,</span><span style="color: #000000;">4</span><span style="color: #0000FF;">},{</span><span style="color: #000000;">5</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"six"</span><span style="color: #0000FF;">})</span>
<span style="color: #7060A8;">requires</span><span style="color: #0000FF;">(</span><span style="color: #008000;">"1.0.2"</span><span style="color: #0000FF;">)</span> <span style="color: #000080;font-style:italic;">-- (map.e incompatible with p2js before that)</span>
<span style="color: #008080;">include</span> <span style="color: #000000;">builtins</span><span style="color: #0000FF;">\</span><span style="color: #000000;">map</span><span style="color: #0000FF;">.</span><span style="color: #000000;">e</span>
<span style="color: #0000FF;">?</span><span style="color: #000000;">pairs</span><span style="color: #0000FF;">()</span>
<span style="color: #0000FF;">?</span><span style="color: #000000;">keys</span><span style="color: #0000FF;">()</span>
<span style="color: #0000FF;">?</span><span style="color: #000000;">values</span><span style="color: #0000FF;">()</span>
<!--</syntaxhighlight>-->
{{out}}
<pre>
{{2,"duo"},{{3,4},{5,"six"}},{"one",1}}
{2,{3,4},"one"}
{"duo",{5,"six"},1}
</pre>
=={{header|Phixmonti}}==
<syntaxhighlight lang="phixmonti">include ..\Utilitys.pmt
def getd /# dict key -- dict data #/
swap 1 get rot find nip
dup if
swap 2 get rot get nip
else
drop "Unfound"
endif
enddef
def setd /# dict ( key data ) -- dict #/
1 get var ikey
2 get var idata
drop
1 get ikey find var p drop
p if
2 get idata p set 2 set
else
2 get idata 0 put 2 set
1 get ikey 0 put 1 set
endif
enddef
def pair /# dict n -- dict ( k d ) #/
1 over 2 tolist var ikey
2 swap 2 tolist var idata
ikey sget
swap idata sget rot swap
2 tolist
enddef
def scandict /# dict n -- dict ( ) #/
var n
1 get len nip
for
pair
n if n get nip endif
print nl
endfor
enddef
def pairs /# dict -- dict ( ) #/
0 scandict
enddef
def keys
1 scandict
enddef
def values
2 scandict
enddef
/# ---------- MAIN ---------- #/
( ( ) ( ) )
( "one" 1 ) setd
( 2 "duo" ) setd
( ( 3 4 ) ( 5 "six" ) ) setd
pairs nl
keys nl
values
</syntaxhighlight>
=={{header|PHP}}==
<
$pairs = array( "hello" => 1,
"world" => 2,
Line 876 ⟶ 2,962:
echo "values = $value\n";
}
?></
=={{header|Picat}}==
<syntaxhighlight lang="picat">go =>
Map = new_map([1=one,2=two,3=three,4=four]),
foreach(K=V in Map)
println(K=V)
end,
nl,
println(keys=Map.keys),
foreach(K in Map.keys.sort)
println(K=Map.get(K))
end,
nl,
println(values=Map.values),
foreach(V in Map.values.sort)
% This works but gets a warning: nonlocal_var_in_iterator_pattern
% println(V=[K : K=V in Map])
% No warning:
println(V=[K : K=V1 in Map,V1 == V])
end,
nl.</syntaxhighlight>
{{out}}
<pre>1 = one
2 = two
3 = three
4 = four
keys = [1,2,3,4]
1 = one
2 = two
3 = three
4 = four
values = [one,two,three,four]
four = [4]
one = [1]
three = [3]
two = [2]</pre>
=={{header|PicoLisp}}==
===Using properties===
<
(put 'A 'bar 10)
(put 'A 'baz 15)
Line 891 ⟶ 3,020:
: (mapcar car (getl 'A)) # Get all values
-> (15 10 5)</
===Using an index tree===
<
(idx 'A (def "bar" 10) T)
(idx 'A (def "baz" 15) T)
Line 904 ⟶ 3,033:
: (mapcar val (idx 'A)) # Get all values
-> (10 15 5)</
=={{header|Pike}}==
Line 910 ⟶ 3,039:
the order is deterministic however.
<syntaxhighlight lang="pike">
mapping(string:string) m = ([ "A":"a", "B":"b", "C":"c" ]);
foreach(m; string key; string value)
Line 932 ⟶ 3,061:
Result: bac
</syntaxhighlight>
=={{header|PostScript}}==
<syntaxhighlight lang="postscript">
% over keys and values
<</a 1 /b 2 /c 3>> {= =} forall
% just keys
<</a 1 /b 2 /c 3>> {= } forall
% just values
<</a 1 /b 2 /c 3>> {pop =} forall
</syntaxhighlight>
=={{header|Potion}}==
We can traverse tables by key or by key and val. We cannot traverse tables only by val.
<syntaxhighlight lang="potion">mydictionary = (red=0xff0000, green=0x00ff00, blue=0x0000ff)
mydictionary each (key, val): (key, ":", val, "\n") join print.
mydictionary each (key): (key, "\n") join print.</syntaxhighlight>
=={{header|PowerShell}}==
Using the following hash table:
<syntaxhighlight lang="powershell">$h = @{ 'a' = 1; 'b' = 2; 'c' = 3 }</syntaxhighlight>
Iterating over the key/value pairs is slightly cumbersome as it requires an explicit call to <code>GetEnumerator</code>:
<syntaxhighlight lang="powershell">$h.GetEnumerator() | ForEach-Object { Write-Host Key: $_.Name, Value: $_.Value }</syntaxhighlight>
A <code>foreach</code> statement can also be used:
<syntaxhighlight lang="powershell">foreach ($e in $h.GetEnumerator()) {
Write-Host Key: $e.Name, Value: $e.Value
}</syntaxhighlight>
Iterating over the keys:
<syntaxhighlight lang="powershell">$h.Keys | ForEach-Object { Write-Host Key: $_ }
foreach ($k in $h.Keys) {
Write-Host Key: $k
}</syntaxhighlight>
Iterating over the values:
<syntaxhighlight lang="powershell">$h.Values | ForEach-Object { Write-Host Value: $_ }
foreach ($v in $h.Values) {
Write-Host Value: $v
}</syntaxhighlight>
=={{header|Prolog}}==
Following the example at [[Associative_array/Creation#Prolog|Associative Array Creation]]
(with the understanding that using a predicate to store a hash does not prevent a "key"
from having more than one value):
<syntaxhighlight lang="prolog">
assert( mymap(key1,value1) ).
assert( mymap(key2,value1) ).
</syntaxhighlight>
To perform the specific task at hand:
<syntaxhighlight lang="prolog">
?- forall( mymap(Key,Value), writeln( [Key,Value]) ).
[key1,value1]
[key2,value1]
</syntaxhighlight>
In Prolog, however, iteration is "built-in". For example:
<syntaxhighlight lang="prolog">
?- mymap(key1, Y).
Y = value1.
?- mymap(X, value1).
X = key1 ;
X = key2.
</syntaxhighlight>
To construct the list of keys:
<syntaxhighlight lang="prolog">
?- findall( X, mymap(X,value1), Xs).
Xs = [key1, key2].
</syntaxhighlight>
To construct the list of distinct values:
<syntaxhighlight lang="prolog">
?- findall( Y, mymap(key1,Y), Ys).
Ys = [value1].
</syntaxhighlight>
=={{header|PureBasic}}==
Hashes are a built-in type called Map in Purebasic.
<
dict("de") = "German"
dict("en") = "English"
Line 943 ⟶ 3,152:
ForEach dict()
Debug MapKey(dict()) + ":" + dict()
Next</
=={{header|Python}}==
<
"world": 31,
"!" : 71 }
Line 963 ⟶ 3,172:
# iterating over values:
for value in myDict.values():
print ("value = %s" % value)</
=={{header|
<syntaxhighlight lang="qb64">
'dictionary is not native data type of QB64
' here a dictionary engine using a string to store data
Dim Shared Skey As String * 1, SValue As String * 1, EValue As String * 1
Skey = Chr$(0)
SValue = Chr$(1)
EValue = Chr$(255)
'Demo area---------------->
Dim MyDictionary As String
If ChangeValue(MyDictionary, "a", "Ananas") Then Print "added new couple key value"
If ChangeValue(MyDictionary, "b", "Banana") Then Print "added new couple key value"
If ChangeValue(MyDictionary, "c", "cherry") Then Print "added new couple key value"
If ChangeValue(MyDictionary, "d", "Drake") Then Print "added new couple key value"
If ChangeValue(MyDictionary, "e", "Elm") Then Print "added new couple key value"
If ChangeValue(MyDictionary, "f", "Fire") Then Print "added new couple key value"
Print LenDict(MyDictionary)
Print "to key e there is "; GetDict$(MyDictionary, "e")
Print "to key e there is "; GetDict$(MyDictionary, "a")
If ChangeValue(MyDictionary, "e", "Elephant") Then Print " changed value of key passed"
Print "to key e there is "; GetDict$(MyDictionary, "e")
If Not (EraseKeyValue(MyDictionary, "e")) Then Print " Failed to erase key value passed" Else Print "Erased key value passed"
If GetDict$(MyDictionary, "e") = "" Then Print " No couple key value found for key value 'e'"
If ChangeKey(MyDictionary, "e", "f") = 0 Then
Print "key -a- has value "; GetDict$(MyDictionary, "a")
Print "we change key a to key e "
If ChangeKey(MyDictionary, "a", "e") = -1 Then
Print "key -a- has value "; GetDict$(MyDictionary, "a")
Print "key -e- has value "; GetDict$(MyDictionary, "e")
End If
End If
If InsertCouple(MyDictionary, "c", "m", "mellon") = -1 Then
Print " New couple inserted after key -c- "; GetDict$(MyDictionary, "c")
Print " new couple is key -m- "; GetDict$(MyDictionary, "m")
End If
Print LenDict(MyDictionary)
' End demo area --------------->
End
' it returns value/s for a key
Function GetDict$ (dict As String, Keys As String)
Dim StartK As Integer, StartV As Integer, EndV As Integer
StartK = InStr(dict, Skey + Keys + SValue)
StartV = InStr(StartK, dict, SValue)
EndV = InStr(StartV, dict, EValue)
If StartK = 0 Then GetDict$ = "" Else GetDict = Mid$(dict, StartV + 1, EndV - StartV)
End Function
' it changes value of a key or append the couple key, newvalue if key is new
Function ChangeValue (dict As String, Keys As String, NewValue As String)
ChangeValue = 0
Dim StartK As Integer, StartV As Integer, EndV As Integer
StartK = InStr(dict, Skey + Keys + SValue)
StartV = InStr(StartK, dict, SValue)
EndV = InStr(StartV, dict, EValue)
If StartK = 0 Then
dict = dict + Skey + Keys + SValue + NewValue + EValue
Else
dict = Left$(dict, StartV) + NewValue + Right$(dict, Len(dict) - EndV + 1)
End If
ChangeValue = -1
End Function
'it changes a key if it is in the dictionary
Function ChangeKey (dict As String, Keys As String, NewKey As String)
ChangeKey = 0
Dim StartK As Integer, StartV As Integer
StartK = InStr(dict, Skey + Keys + SValue)
StartV = InStr(StartK, dict, SValue)
If StartK = 0 Then
Print "Key " + Keys + " not found"
Exit Function
Else
dict = Left$(dict, StartK) + NewKey + Right$(dict, Len(dict) - StartV + 1)
End If
ChangeKey = -1
End Function
'it erases the couple key value
Function EraseKeyValue (dict As String, keys As String)
EraseKeyValue = 0
Dim StartK As Integer, StartV As Integer, EndV As Integer
StartK = InStr(dict, Skey + keys + SValue)
StartV = InStr(StartK, dict, SValue)
EndV = InStr(StartV, dict, EValue)
If StartK = 0 Then
Exit Function
Else
dict = Left$(dict, StartK - 1) + Right$(dict, Len(dict) - EndV + 1)
End If
EraseKeyValue = -1
End Function
'it inserts a couple after a defined key, if key is not in dictionary it append couple key value
Function InsertCouple (dict As String, SKeys As String, Keys As String, Value As String)
InsertCouple = 0
Dim StartK As Integer, StartV As Integer, EndV As Integer
StartK = InStr(dict, Skey + SKeys + SValue)
StartV = InStr(StartK, dict, SValue)
EndV = InStr(StartV, dict, EValue)
If StartK = 0 Then
dict = dict + Skey + Keys + SValue + Value + EValue
Else
dict = Left$(dict, EndV) + Skey + Keys + SValue + Value + EValue + Right$(dict, Len(dict) - EndV + 1)
End If
InsertCouple = -1
End Function
Function LenDict (dict As String)
LenDict = 0
Dim a As Integer, count As Integer
If Len(dict) <= 0 Then Exit Function
While a <= Len(dict)
a = InStr(a + 1, dict, EValue)
If a > 0 Then count = count + 1 Else Exit While
Wend
LenDict = count
End Function
</syntaxhighlight>
=={{header|R}}==
R lacks a native representation of key-value pairs, but different structures allow named elements, which provide similar functionality.
=== environment example ===
<syntaxhighlight lang="r">> env <- new.env()
> env[["x"]] <- 123
> env[["x"]]</syntaxhighlight>
<pre>[1] 123</pre>
<syntaxhighlight lang="r">> index <- "1"
> env[[index]] <- "rainfed hay"
> for (name in ls(env)) {
+ cat(sprintf('index=%s, value=%s\n', name, env[[name]]))
+ }</syntaxhighlight>
<pre>index=1, value=rainfed hay
index=x, value=123</pre>
=== vector example ===
<syntaxhighlight lang="r">> x <- c(hello=1, world=2, "!"=3)
> print(x["!"])</syntaxhighlight>
<pre>!
3</pre>
<syntaxhighlight lang="r">> print(unname(x["!"]))</syntaxhighlight>
<pre>[1] 3</pre>
=== list example ===
<syntaxhighlight lang="r">> a <- list(a=1, b=2, c=3.14, d="xyz")
> print(a$a)</syntaxhighlight>
<pre>[1] 1</pre>
<syntaxhighlight lang="r">> print(a$d)</syntaxhighlight>
<pre>[1] "xyz"</pre>
=={{header|Racket}}==
Using the dictionary interface, different data structures can be treated as an associative array in Racket.
<syntaxhighlight lang="racket">
#lang racket
(define dict1 #hash((apple . 5) (orange . 10))) ; hash table
(define dict2 '((apple . 5) (orange . 10))) ; a-list
(define dict3 (vector "a" "b" "c")) ; vector (integer keys)
(dict-keys dict1) ; => '(orange apple)
(dict-values dict2) ; => '(5 10)
(for/list ([(k v) (in-dict dict3)]) ; => '("0 -> a" "1 -> b" "2 -> c")
(format "~a -> ~a" k v))
</syntaxhighlight>
=={{header|Raku}}==
(formerly Perl 6)
{{works with|Rakudo|2015.12}}
<syntaxhighlight lang="raku" line>my %pairs = hello => 13, world => 31, '!' => 71;
for %pairs.kv -> $k, $v {
say "(k,v) = ($k, $v)";
}
# Stable order
for %pairs.sort(*.value)>>.kv -> ($k, $v) {
say "(k,v) = ($k, $v)";
}
{ say "$^a => $^b" } for %pairs.kv;
say "key = $_" for %pairs.keys;
say "value = $_" for %pairs.values;</syntaxhighlight>
=={{header|REXX}}==
<syntaxhighlight lang="rexx">/*REXX program demonstrates how to set and display values for an associative array. */
/*╔════════════════════════════════════════════════════════════════════════════════════╗
║ The (below) two REXX statements aren't really necessary, but it shows how to ║
║ define any and all entries in a associative array so that if a "key" is used that ║
║ isn't defined, it can be displayed to indicate such, or its value can be checked ║
║ to determine if a particular associative array element has been set (defined). ║
╚════════════════════════════════════════════════════════════════════════════════════╝*/
stateF.= ' [not defined yet] ' /*sets any/all state former capitals.*/
stateN.= ' [not defined yet] ' /*sets any/all state names. */
w = 0 /*the maximum length of a state name.*/
stateL =
/*╔════════════════════════════════════════════════════════════════════════════════════╗
║ The list of states (empty as of now). It's convenient to have them in alphabetic ║
║ order; they'll be listed in the order as they are in the REXX program below). ║
║ In REXX, when a key is used (for a stemmed array, as they are called in REXX), ║
║ and the key isn't assigned a value, the key's name is stored (internally) as ║
║ uppercase (Latin) characters (as in the examples below. If the key has a ║
║ a value, the key's value is used as is (i.e.: no upper translation is performed).║
║ Actually, any characters can be used, including blank(s) and non─displayable ║
║ characters (including '00'x, 'ff'x, commas, periods, quotes, ···). ║
╚════════════════════════════════════════════════════════════════════════════════════╝*/
call setSC 'al', "Alabama" , 'Tuscaloosa'
call setSC 'ca', "California" , 'Benicia'
call setSC 'co', "Colorado" , 'Denver City'
call setSC 'ct', "Connecticut" , 'Hartford and New Haven (jointly)'
call setSC 'de', "Delaware" , 'New-Castle'
call setSC 'ga', "Georgia" , 'Milledgeville'
call setSC 'il', "Illinois" , 'Vandalia'
call setSC 'in', "Indiana" , 'Corydon'
call setSC 'ia', "Iowa" , 'Iowa City'
call setSC 'la', "Louisiana" , 'New Orleans'
call setSC 'me', "Maine" , 'Portland'
call setSC 'mi', "Michigan" , 'Detroit'
call setSC 'ms', "Mississippi" , 'Natchez'
call setSC 'mo', "Missouri" , 'Saint Charles'
call setSC 'mt', "Montana" , 'Virginia City'
call setSC 'ne', "Nebraska" , 'Lancaster'
call setSC 'nh', "New Hampshire" , 'Exeter'
call setSC 'ny', "New York" , 'New York'
call setSC 'nc', "North Carolina" , 'Fayetteville'
call setSC 'oh', "Ohio" , 'Chillicothe'
call setSC 'ok', "Oklahoma" , 'Guthrie'
call setSC 'pa', "Pennsylvania" , 'Lancaster'
call setSC 'sc', "South Carolina" , 'Charlestown'
call setSC 'tn', "Tennessee" , 'Murfreesboro'
call setSC 'vt', "Vermont" , 'Windsor'
do j=1 for words(stateL) /*show all capitals that were defined. */
$= word(stateL, j) /*get the next (USA) state in the list.*/
say 'the former capital of ('$") " left(stateN.$, w) " was " stateC.$
end /*j*/ /* [↑] show states that were defined.*/
exit /*stick a fork in it, we're all done. */
/*──────────────────────────────────────────────────────────────────────────────────────*/
setSC: parse arg code,name,cap; upper code /*get code, name & cap.; uppercase code*/
stateL= stateL code /*keep a list of all the US state codes*/
stateN.code= name; w= max(w,length(name)) /*define the state's name; max width. */
stateC.code= cap /* " " " code to the capital*/
return /*return to invoker, SETSC is finished.*/</syntaxhighlight>
{{out|output|text= when using the internal default input:}}
<pre>
the former capital of (AL) Alabama was Tuscaloosa
the former capital of (CA) California was Benicia
the former capital of (CO) Colorado was Denver City
the former capital of (CT) Connecticut was Hartford and New Haven (jointly)
the former capital of (DE) Delaware was New-Castle
the former capital of (GA) Georgia was Milledgeville
the former capital of (IL) Illinois was Vandalia
the former capital of (IN) Indiana was Corydon
the former capital of (IA) Iowa was Iowa City
the former capital of (LA) Louisiana was New Orleans
the former capital of (ME) Maine was Portland
the former capital of (MI) Michigan was Detroit
the former capital of (MS) Mississippi was Natchez
the former capital of (MO) Missouri was Saint Charles
the former capital of (MT) Montana was Virginia City
the former capital of (NE) Nebraska was Lancaster
the former capital of (NH) New Hampshire was Exeter
the former capital of (NY) New York was New York
the former capital of (NC) North Carolina was Fayetteville
the former capital of (OH) Ohio was Chillicothe
the former capital of (OK) Oklahoma was Guthrie
the former capital of (PA) Pennsylvania was Lancaster
the former capital of (SC) South Carolina was Charlestown
the former capital of (TN) Tennessee was Murfreesboro
the former capital of (VT) Vermont was Windsor
</pre>
When this example was started, the intention was to list the former capitals by key. Unfortunately, there's a duplicate capital (Lancaster).
<br><br>
=={{header|Ring}}==
<syntaxhighlight lang="ring">
# Project : Associative array/Iteration
lst = [["hello", 13], ["world", 31], ["!", 71]]
for n = 1 to len(lst)
see lst[n][1] + " : " + lst[n][2] + nl
next
</syntaxhighlight>
Output:
<pre>
hello : 13
world : 31
! : 71
</pre>
=={{header|RLaB}}==
Associative arrays are called ''lists'' in RLaB.
<syntaxhighlight lang="rlab">
x = <<>>; // create an empty list
x.hello = 1;
Line 1,036 ⟶ 3,503:
</syntaxhighlight>
=={{header|Ruby}}==
<
"world" => 31,
"!" => 71 }
# iterating over key-value pairs:
# or
# iterating over keys:
# iterating over values:
another way:
<syntaxhighlight lang="ruby">for key, value in my_dict
puts "key = #{key}, value = #{value}"
end
for key in my_dict.keys
puts "key = #{key}"
end
for value in my_dict.values
puts "value = #{value}"
end</syntaxhighlight>
{{out}}
<pre>
key = hello, value = 13
key = world, value = 31
key = !, value = 71
key = hello
key = world
key = !
value = 13
value = 31
value = 71
</pre>
=={{header|Rust}}==
<syntaxhighlight lang="rust">use std::collections::HashMap;
fn main() {
let mut olympic_medals = HashMap::new();
olympic_medals.insert("United States", (1072, 859, 749));
olympic_medals.insert("Soviet Union", (473, 376, 355));
olympic_medals.insert("Great Britain", (246, 276, 284));
olympic_medals.insert("Germany", (252, 260, 270));
for (country, medals) in olympic_medals {
println!("{} has had {} gold medals, {} silver medals, and {} bronze medals",
country, medals.0, medals.1, medals.2);
}
}</syntaxhighlight>
{{out}}
Note that <code>HashMap</code> does not preserve order (if this is important, <code>std::collections::BTreeMap</code> is what you want.)
<pre>
Germany has had 252 gold medals, 260 silver medals, and 270 bronze medals
United States has had 1072 gold medals, 859 silver medals, and 749 bronze medals
Soviet Union has had 473 gold medals, 376 silver medals, and 355 bronze medals
Great Britain has had 246 gold medals, 276 silver medals, and 284 bronze medals
</pre>
=={{header|Scala}}==
<syntaxhighlight lang="scala">val m = Map("Amsterdam" -> "Netherlands", "New York" -> "USA", "Heemstede" -> "Netherlands")
println(f"Key->Value: ${m.mkString(", ")}%s")
println(f"Pairs: ${m.toList.mkString(", ")}%s")
println(f"Keys: ${m.keys.mkString(", ")}%s")
println(f"Values: ${m.values.mkString(", ")}%s")
println(f"Unique values: ${m.values.toSet.mkString(", ")}%s")</syntaxhighlight>{{out}}<pre>
Key->Value: Amsterdam -> Netherlands, New York -> USA, Heemstede -> Netherlands
Pairs: (Amsterdam,Netherlands), (New York,USA), (Heemstede,Netherlands)
Keys: Amsterdam, New York, Heemstede
Values: Netherlands, USA, Netherlands
Unique values: Netherlands, USA
</pre>
=={{header|Scheme}}==
{{works with|Gauche Scheme}}
<syntaxhighlight lang="scheme">
;; Create an associative array (hash-table) whose keys are strings:
(define table (hash-table 'string=?
'("hello" . 0) '("world" . 22) '("!" . 999)))
;; Iterate over the table, passing the key and the value of each entry
;; as arguments to a function:
(hash-table-for-each
table
;; Create by "partial application" a function that accepts 2 arguments,
;; the key and the value:
(pa$ format #t "Key = ~a, Value = ~a\n"))</syntaxhighlight>
Output:
<pre>
Key = !, Value = 999
Key = world, Value = 22
Key = hello, Value = 0
</pre>
<syntaxhighlight lang="scheme">
;; Iterate over the table and create a list of the keys and the
;; altered values:
(hash-table-map
table
(lambda (key val) (list key (+ val 5000))))
;; Create a new table that has the same keys but altered values.
(use gauche.collection)
(map-to <hash-table>
(lambda (k-v) (cons (car k-v) (+ (cdr k-v) 5000)))
table)
</syntaxhighlight>
To get a list of the keys or of the values of the table,
use one of the following:
<pre>
(hash-table-keys table)
(hash-table-values table)
</pre>
=== For [[Associative_array/Creation#A_persistent_associative_array_from_scratch|''persistent'' associative arrays]] ===
{{works with|CHICKEN|5.3.0}}
{{libheader|r7rs}}
{{libheader|srfi-1}}
Here is a variant of [[Associative_array/Creation#A_persistent_associative_array_from_scratch|''persistent'' associative arrays]] that includes ''generators''. Such generators are functionally equivalent to iterators; the only important difference is they are executable procedures rather than passive objects. Note also that, because these associative arrays are persistent, iterating through their structure is much safer than it would be in a conventional hash table, which might change or even disappear while you were doing the iteration.
What I present here is a trimmed-down version of what you might find in a prefabricated library, such as an implementation of SRFI-125. I suppose part of my point in presenting this is that ‘associative arrays’ are not actually part of the Scheme language (even in R6RS), but rather are library add-ons. Someone else has done the sort of thing I am demonstrating here. This is in contrast to, say, Awk, or Icon, where associative ‘arrays’ ''really are'' built into the language.
(To save space, I have removed comments you can read at the section for [[Associative_array/Creation#A_persistent_associative_array_from_scratch|''persistent'' associative arrays]].)
<syntaxhighlight lang="scheme">(cond-expand
(r7rs)
(chicken (import r7rs)))
(define-library (suspendable-procedures)
(export &fail failure? success? suspend fail-forever
make-generator-procedure)
(import (scheme base))
(begin
(define-record-type <&fail>
(make-the-one-unique-&fail-that-you-must-not-make-twice)
do-not-use-this:&fail?)
(define &fail
(make-the-one-unique-&fail-that-you-must-not-make-twice))
(define (failure? f) (eq? f &fail))
(define (success? f) (not (failure? f)))
(define *suspend* (make-parameter (lambda (x) x)))
(define (suspend v) ((*suspend*) v))
(define (fail-forever)
(let loop ()
(suspend &fail)
(loop)))
(define (make-generator-procedure thunk)
;; This is for making a suspendable procedure that takes no
;; arguments when resumed. The result is a simple generator of
;; values.
(define (next-run return)
(define (my-suspend v)
(set! return (call/cc (lambda (resumption-point)
(set! next-run resumption-point)
(return v)))))
(parameterize ((*suspend* my-suspend))
(suspend (thunk))
(fail-forever)))
(lambda () (call/cc next-run)))
)) ;; end library (suspendable-procedures)
(define-library (avl-trees)
;;
;; Persistent (that is, ‘immutable’) AVL trees for R7RS Scheme.
;;
;; References:
;;
;; * Niklaus Wirth, 1976. Algorithms + Data Structures =
;; Programs. Prentice-Hall, Englewood Cliffs, New Jersey.
;;
;; * Niklaus Wirth, 2004. Algorithms and Data Structures. Updated
;; by Fyodor Tkachov, 2014.
;;
(export avl-make-generator)
(export avl avl? avl-empty? avl-insert avl-search-values)
(export avl-check-usage)
(import (scheme base))
(import (scheme case-lambda))
(import (scheme process-context))
(import (scheme write))
(import (suspendable-procedures))
(begin
(define-syntax avl-check-usage
(syntax-rules ()
((_ pred msg)
(or pred (usage-error msg)))))
(define-record-type <avl>
(%avl key data bal left right)
avl?
(key %key)
(data %data)
(bal %bal)
(left %left)
(right %right))
(define avl-make-generator
(case-lambda
((tree) (avl-make-generator tree 1))
((tree direction)
(if (negative? direction)
(make-generator-procedure
(lambda ()
(define (traverse p)
(unless (or (not p) (avl-empty? p))
(traverse (%right p))
(suspend (cons (%key p) (%data p)))
(traverse (%left p)))
&fail)
(traverse tree)))
(make-generator-procedure
(lambda ()
(define (traverse p)
(unless (or (not p) (avl-empty? p))
(traverse (%left p))
(suspend (cons (%key p) (%data p)))
(traverse (%right p)))
&fail)
(traverse tree)))))))
(define (avl) (%avl #f #f #f #f #f))
(define (avl-empty? tree)
(avl-check-usage
(avl? tree)
"avl-empty? expects an AVL tree as argument")
(not (%bal tree)))
(define (avl-search-values pred<? tree key)
(define (search p)
(if (not p)
(values #f #f)
(let ((k (%key p)))
(cond ((pred<? key k) (search (%left p)))
((pred<? k key) (search (%right p)))
(else (values (%data p) #t))))))
(avl-check-usage
(procedure? pred<?)
"avl-search-values expects a procedure as first argument")
(if (avl-empty? tree)
(values #f #f)
(search tree)))
(define (avl-insert pred<? tree key data)
(define (search p fix-balance?)
(cond
((not p)
(values (%avl key data 0 #f #f) #t))
((pred<? key (%key p))
(let-values (((p1 fix-balance?)
(search (%left p) fix-balance?)))
(cond
((not fix-balance?)
(let ((p^ (%avl (%key p) (%data p) (%bal p)
p1 (%right p))))
(values p^ #f)))
(else
(case (%bal p)
((1)
(let ((p^ (%avl (%key p) (%data p) 0
p1 (%right p))))
(values p^ #f)))
((0)
(let ((p^ (%avl (%key p) (%data p) -1
p1 (%right p))))
(values p^ fix-balance?)))
((-1)
(case (%bal p1)
((-1)
(let* ((p^ (%avl (%key p) (%data p) 0
(%right p1) (%right p)))
(p1^ (%avl (%key p1) (%data p1) 0
(%left p1) p^)))
(values p1^ #f)))
((0 1)
(let* ((p2 (%right p1))
(bal2 (%bal p2))
(p^ (%avl (%key p) (%data p)
(- (min bal2 0))
(%right p2) (%right p)))
(p1^ (%avl (%key p1) (%data p1)
(- (max bal2 0))
(%left p1) (%left p2)))
(p2^ (%avl (%key p2) (%data p2) 0
p1^ p^)))
(values p2^ #f)))
(else (internal-error))))
(else (internal-error)))))))
((pred<? (%key p) key)
(let-values (((p1 fix-balance?)
(search (%right p) fix-balance?)))
(cond
((not fix-balance?)
(let ((p^ (%avl (%key p) (%data p) (%bal p)
(%left p) p1)))
(values p^ #f)))
(else
(case (%bal p)
((-1)
(let ((p^ (%avl (%key p) (%data p) 0
(%left p) p1)))
(values p^ #f)))
((0)
(let ((p^ (%avl (%key p) (%data p) 1
(%left p) p1)))
(values p^ fix-balance?)))
((1)
(case (%bal p1)
((1)
(let* ((p^ (%avl (%key p) (%data p) 0
(%left p) (%left p1)))
(p1^ (%avl (%key p1) (%data p1) 0
p^ (%right p1))))
(values p1^ #f)))
((-1 0)
(let* ((p2 (%left p1))
(bal2 (%bal p2))
(p^ (%avl (%key p) (%data p)
(- (max bal2 0))
(%left p) (%left p2)))
(p1^ (%avl (%key p1) (%data p1)
(- (min bal2 0))
(%right p2) (%right p1)))
(p2^ (%avl (%key p2) (%data p2) 0
p^ p1^)))
(values p2^ #f)))
(else (internal-error))))
(else (internal-error)))))))
(else
(values (%avl key data (%bal p) (%left p) (%right p))
#f))))
(avl-check-usage
(procedure? pred<?)
"avl-insert expects a procedure as first argument")
(if (avl-empty? tree)
(%avl key data 0 #f #f)
(let-values (((p fix-balance?) (search tree #f)))
p)))
(define (internal-error)
(display "internal error\n" (current-error-port))
(emergency-exit 123))
(define (usage-error msg)
(display "Procedure usage error:\n" (current-error-port))
(display " " (current-error-port))
(display msg (current-error-port))
(newline (current-error-port))
(exit 1))
)) ;; end library (avl-trees)
(define-library (associative-arrays)
;;
;; Persistent associative ‘arrays’ for R7RS Scheme.
;;
;; The structure is not actually an array, but is made of AVL trees
;; and association lists. Given a good hash function, it should
;; average logarithmic performance.
;;
(export assoc-array-make-pair-generator
assoc-array-make-key-generator
assoc-array-make-data-generator)
(export assoc-array assoc-array? assoc-array-set assoc-array-ref)
(import (scheme base))
(import (scheme case-lambda))
(import (scheme write))
(import (suspendable-procedures))
(import (avl-trees))
(cond-expand
(chicken (import (only (srfi 1) alist-delete)))
;; Insert whatever you need here for your Scheme.
(else))
(begin
(define-record-type <assoc-array>
(%assoc-array hashfunc pred=? default table)
assoc-array?
(hashfunc %hashfunc)
(pred=? %pred=?)
(default %default)
(table %table))
(define (assoc-array-make-generator array kind)
(define tree-traverser (avl-make-generator (%table array)))
(define get-desired-part
(cond ((eq? kind 'key) (lambda (pair) (car pair)))
((eq? kind 'data) (lambda (pair) (cdr pair)))
(else (lambda (pair) pair))))
(make-generator-procedure
(lambda ()
(let traverse ()
(let ((tree-entry (tree-traverser)))
(when (success? tree-entry)
(let scan-lst ((lst (cdr tree-entry)))
(when (pair? lst)
(suspend (get-desired-part (car lst)))
(scan-lst (cdr lst))))
(traverse))))
&fail)))
(define (assoc-array-make-pair-generator array)
(assoc-array-make-generator array 'pair))
(define (assoc-array-make-key-generator array)
(assoc-array-make-generator array 'key))
(define (assoc-array-make-data-generator array)
(assoc-array-make-generator array 'data))
(define assoc-array
(case-lambda
((hashfunc)
(let ((pred=? equal?)
(default #f))
(assoc-array hashfunc pred=? default)))
((hashfunc pred=?)
(let ((default #f))
(assoc-array hashfunc pred=? default)))
((hashfunc pred=? default)
(%assoc-array hashfunc pred=? default (avl)))))
(define (assoc-array-set array key data)
(let ((hashfunc (%hashfunc array))
(pred=? (%pred=? array))
(default (%default array))
(table (%table array)))
(let ((hash-value (hashfunc key)))
(let*-values
(((alst found?) (avl-search-values < table hash-value)))
(cond
(found?
(let* ((alst (alist-delete key alst pred=?))
(alst `((,key . ,data) . ,alst))
(table (avl-insert < table hash-value alst)))
(%assoc-array hashfunc pred=? default table)))
(else
(let* ((alst `((,key . ,data)))
(table (avl-insert < table hash-value alst)))
(%assoc-array hashfunc pred=? default table))))))))
(define (assoc-array-ref array key)
(let* ((hashfunc (%hashfunc array))
(hash-value (hashfunc key)))
(let*-values
(((alst found?)
(avl-search-values < (%table array) hash-value)))
(if found?
(let ((pair (assoc key alst (%pred=? array))))
(if pair
(cdr pair)
(%default array)))
(%default array)))))
)) ;; end library (associative-arrays)
(cond-expand
(DEMONSTRATION
(begin
(import (scheme base))
(import (scheme write))
(import (suspendable-procedures))
(import (associative-arrays))
(define (hashfunc s)
;; Using Knuth’s random number generator to concoct a quick and
;; dirty and probably very bad hash function. It should be much
;; better to use something like SpookyHash, but this is a demo.
(define a 6364136223846793005)
(define c 1442695040888963407)
(define M (expt 2 64))
(let ((n (string-length s))
(h 123))
(do ((i 0 (+ i 1)))
((= i n))
(let* ((x (char->integer (string-ref s i)))
(x (+ (* a (+ h x)) c)))
(set! h (truncate-remainder x M))))
h))
(define a (assoc-array hashfunc))
;; Fill the associative array ‘a’ with (string . number)
;; associations.
(do ((i 1 (+ i 1)))
((= i 11))
(set! a (assoc-array-set a (number->string i) i)))
;; Go through the association pairs (in arbitrary order) with a
;; generator.
(let ((gen (assoc-array-make-pair-generator a)))
(do ((pair (gen) (gen)))
((failure? pair))
(write pair) (display " "))
(newline))
;; Go through the keys (in arbitrary order) with a generator.
(let ((gen (assoc-array-make-key-generator a)))
(do ((key (gen) (gen)))
((failure? key))
(write key) (display " "))
(newline))
;; Go through the values (in arbitrary order) with a generator.
(let ((gen (assoc-array-make-data-generator a)))
(do ((value (gen) (gen)))
((failure? value))
(write value) (display " "))
(newline))
))
(else))</syntaxhighlight>
{{out}}
<pre>$ csc -DDEMONSTRATION -R r7rs -X r7rs associative_array_with_generators.scm && ./associative_array_with_generators
("3" . 3) ("6" . 6) ("9" . 9) ("1" . 1) ("4" . 4) ("7" . 7) ("2" . 2) ("10" . 10) ("5" . 5) ("8" . 8)
"3" "6" "9" "1" "4" "7" "2" "10" "5" "8"
3 6 9 1 4 7 2 10 5 8</pre>
=={{header|Seed7}}==
<
const type: dictType is hash [string] integer;
Line 1,113 ⟶ 4,084:
writeln("value = " <& number);
end for;
end func;</
{{out}}
<pre>
key = 3, value = !
Line 1,126 ⟶ 4,097:
value = 1
value = 2
</pre>
=={{header|SenseTalk}}==
<syntaxhighlight lang="sensetalk">put {name:"Fluffy", type:"Rabbit", color:"White"} into animal
put "Carries a watch" into animal's habits
put "The animal: " & animal
put "The keys: " & keys of animal
put "The values: " & animal's values
// Keys and Values
put ,"All Properties:"
repeat with each [key,value] in animal
put !"Key: [[key]] Value: [[value]]"
end repeat
// Keys only
put ,"Keys:"
repeat with each [key] in animal
put key
end repeat
// Values only
put ,"Values:"
repeat with each [,value] in animal
put value
end repeat
// Using an iterator
put ,"Treating the property list as an iterator:"
put animal's nextValue -- calling any of the "next" functions begins iteration
put animal's nextKeyValue
put animal's nextKey
put animal's nextKeyValue
put animal's nextValue -- walking off the end returns a unique endValue
</syntaxhighlight>
{{out}}
<pre>
The animal: {color:"White", habits:"Carries a watch", name:"Fluffy", type:"Rabbit"}
The keys: ["color","habits","name","type"]
The values: ["White","Carries a watch","Fluffy","Rabbit"]
All Properties:
Key: color Value: White
Key: habits Value: Carries a watch
Key: name Value: Fluffy
Key: type Value: Rabbit
Keys:
color
habits
name
type
Values:
White
Carries a watch
Fluffy
Rabbit
Treating the property list as an iterator:
White
["habits","Carries a watch"]
name
["type","Rabbit"]
ⓔ ⓝ ⓓ
</pre>
=={{header|Sidef}}==
<syntaxhighlight lang="ruby">var hash = Hash(
key1 => 'value1',
key2 => 'value2',
)
# Iterate over key-value pairs
hash.each { |key, value|
say "#{key}: #{value}"
}
# Iterate only over keys
hash.keys.each { |key|
say key
}
# Iterate only over values
hash.values.each { |value|
say value
}</syntaxhighlight>
{{out}}
<pre>key1: value1
key2: value2
key1
key2
value1
value2
</pre>
=={{header|Slate}}==
In Slate, all associative mappings inherit from <tt>Mapping</tt>, so they all have the same protocol. Even <tt>Sequence</tt>s obey it, in addition to their own protocol for collections with ordered integer-range keys.
<
pairs keysAndValuesDo: [| :key :value |
inform: '(k, v) = (' ; key printString ; ', ' ; value printString ; ')'
Line 1,141 ⟶ 4,206:
pairs do: [| :value |
inform: 'value = ' ; value printString
].</
=={{header|Smalltalk}}==
{{works with|GNU Smalltalk}}
<
pairs := Dictionary
from: { 'hello' -> 1. 'world' -> 2. '!' -> 3. 'another!' -> 3 }.
Line 1,163 ⟶ 4,228:
pairs do: [ :value |
('value = %1' % { value }) displayNl
].</
We could also obtain a set of keys or a collection of values and iterate over them with "<tt>do:</tt>":
<
(pairs values) do: [ :v | "..." ].</
=={{header|SNOBOL4}}==
Line 1,176 ⟶ 4,241:
{{works with|CSnobol}}
<
t = table()
t<'cat'> = 'meow'
Line 1,191 ⟶ 4,256:
* # Iterate vals
vloop k = k + 1; output = a<k,2> :s(vloop)
end</
=={{header|Stata}}==
<syntaxhighlight lang="stata">mata
// Create an associative array
a=asarray_create()
asarray(a,"one",1)
asarray(a,"two",2)
// Loop over entries
loc=asarray_first(a)
do {
printf("%s %f\n",asarray_key(a,loc),asarray_contents(a,loc))
loc=asarray_next(a,loc)
} while(loc!=NULL)
end</syntaxhighlight>
=={{header|Swift}}==
<syntaxhighlight lang="swift">let myMap = [
"hello": 13,
"world": 31,
"!" : 71 ]
// iterating over key-value pairs:
for (key, value) in myMap {
print("key = \(key), value = \(value)")
}
// Just the keys
for key in myMap.keys
{
print("key = \(key)")
}
// Just the values
for value in myMap.values
{
print("value = \(value)")
}</syntaxhighlight>
=={{header|Tcl}}==
===With Arrays===
<
# list items here...
}
Line 1,210 ⟶ 4,311:
# There is nothing for directly iterating over just the values
# Use the keys+values version and ignore the keys</
===With Dictionaries===
{{works with|Tcl|8.5}}
<
# Iterate over keys and values
Line 1,228 ⟶ 4,329:
foreach value [dict values $myDict] {
puts "value = $value"
}</
=={{header|TXR}}==
<syntaxhighlight lang="txrlisp">(defvarl h (hash))
(each ((k '(a b c))
(v '(1 2 3)))
(set [h k] v))
(dohash (k v h)
(put-line `@k -> @v`))</syntaxhighlight>
{{out|Run}}
<pre>$ txr hash.tl
c -> 3
b -> 2
a -> 1</pre>
=={{header|UNIX Shell}}==
{{works with|ksh93}}
{{works with|bash|4.0 and above}}
<syntaxhighlight lang="bash">typeset -A a=([key1]=value1 [key2]=value2)
# just keys
Line 1,245 ⟶ 4,365:
for key in "${!a[@]}"; do
printf '%s => %s\n' "$key" "${a[$key]}"
done</
{{works with|zsh}}
<
a=(key1 value1 key2 value2)
Line 1,258 ⟶ 4,378:
# keys and values
printf '%s => %s\n' ${(kv)a}</
=={{header|Vala}}==
{{libheader|Gee}}
<syntaxhighlight lang="vala">
using Gee;
void main(){
// declare HashMap
var map = new HashMap<string, double?>();
// set 3 entries
map["pi"] = 3.14;
map["e"] = 2.72;
map["golden"] = 1.62;
// iterate over (key,value) pair
foreach (var elem in map.entries){
string name = elem.key;
double num = elem.value;
stdout.printf("%s,%f\n", name, num);
}
// iterate over keys
foreach (string key in map.keys){
stdout.printf("%s\n", key);
}
// iterate over values
foreach (double num in map.values){
stdout.printf("%f\n", num);
}
}
</syntaxhighlight>
Compile with flag:
<pre>
--pkg gee-1.0
</pre>
{{out}}
<pre>
e,2.720000
golden,1.620000
pi,3.140000
e
golden
pi
2.720000
1.620000
3.140000
</pre>
=={{header|VBA}}==
Dictionaries are similar in VBA and VBScript. Here is how to iterate.
<syntaxhighlight lang="vb">Option Explicit
Sub Test()
Dim h As Object, i As Long, u, v, s
Set h = CreateObject("Scripting.Dictionary")
h.Add "A", 1
h.Add "B", 2
h.Add "C", 3
'Iterate on keys
For Each s In h.Keys
Debug.Print s
Next
'Iterate on values
For Each s In h.Items
Debug.Print s
Next
'Iterate on both keys and values by creating two arrays
u = h.Keys
v = h.Items
For i = 0 To h.Count - 1
Debug.Print u(i), v(i)
Next
End Sub</syntaxhighlight>
=={{header|VBScript}}==
<syntaxhighlight lang="vb">
'instantiate the dictionary object
Set dict = CreateObject("Scripting.Dictionary")
'populate the dictionary or hash table
dict.Add 1,"larry"
dict.Add 2,"curly"
dict.Add 3,"moe"
'iterate key and value pairs
For Each key In dict.Keys
WScript.StdOut.WriteLine key & " - " & dict.Item(key)
Next
</syntaxhighlight>
{{Out}}
<pre>
1 - larry
2 - curly
3 - moe
</pre>
=={{header|Vim Script}}==
<syntaxhighlight lang="vim">let dict = {"apples": 11, "oranges": 25, "pears": 4}
echo "Iterating over key-value pairs"
for [key, value] in items(dict)
echo key " => " value
endfor
echo "\n"
echo "Iterating over keys"
for key in keys(dict)
echo key
endfor
echo "\n"
echo "Iterating over values"
for value in values(dict)
echo value
endfor</syntaxhighlight>
{{Out}}
<pre>Iterating over key-value pairs
oranges => 25
pears => 4
apples => 11
Iterating over keys
oranges
pears
apples
Iterating over values
25
4
11</pre>
=={{header|V (Vlang)}}==
<syntaxhighlight lang="v (vlang)">fn main() {
my_map := {
"hello": 13,
"world": 31,
"!" : 71 }
// iterating over key-value pairs:
for key, value in my_map {
println("key = $key, value = $value")
}
// iterating over keys:
for key,_ in my_map {
println("key = $key")
}
// iterating over values:
for _, value in my_map {
println("value = $value")
}
}</syntaxhighlight>
{{out}}
<pre>key = hello, value = 13
key = world, value = 31
key = !, value = 71
key = hello
key = world
key = !
value = 13
value = 31
value = 71
</pre>
=={{header|Wart}}==
<syntaxhighlight lang="wart">h <- (table 'a 1 'b 2)
each (key val) table
prn key " " val</syntaxhighlight>
{{out}}
<pre>a 1
b 2</pre>
=={{header|Wren}}==
Note that Wren makes no guarantee about iteration order which is not necessarily the same order in which the entries were added.
<syntaxhighlight lang="wren">// create a new map with four entries
var capitals = {
"France": "Paris",
"Germany": "Berlin",
"Russia": "Moscow",
"Spain": "Madrid"
}
// iterate through the map and print out the key/value pairs
for (c in capitals) System.print([c.key, c.value])
System.print()
// iterate though the map and print out just the keys
for (k in capitals.keys) System.print(k)
System.print()
// iterate though the map and print out just the values
for (v in capitals.values) System.print(v)</syntaxhighlight>
{{out}}
<pre>
[France, Paris]
[Russia, Moscow]
[Germany, Berlin]
[Spain, Madrid]
France
Russia
Germany
Spain
Paris
Moscow
Berlin
Madrid
</pre>
=={{header|XPL0}}==
<syntaxhighlight lang="xpl0">include c:\cxpl\stdlib;
char Dict(10,10);
int Entries;
proc AddEntry(Letter, Greek); \Insert entry into associative array
char Letter, Greek;
[Dict(Entries,0):= Letter;
StrCopy(Greek, @Dict(Entries,1));
Entries:= Entries+1; \(limit checks ignored for simplicity)
];
int I;
[Entries:= 0;
AddEntry(^A, "alpha");
AddEntry(^D, "delta");
AddEntry(^B, "beta");
AddEntry(^C, "gamma");
for I:= 0 to Entries-1 do
[ChOut(0, Dict(I,0)); ChOut(0, ^ ); Text(0, @Dict(I,1)); CrLf(0)];
]</syntaxhighlight>
{{out}}
<pre>
A alpha
D delta
B beta
C gamma
</pre>
=={{header|zkl}}==
<syntaxhighlight lang="zkl">var d=Dictionary("A","alpha","D","delta", "B","beta", "C", "gamma");
d.keys.pump(Console.print,fcn(k){String(k,",")})
d.values.apply("toUpper").println();
d.makeReadOnly(); // can only iterate over k,v pairs if read only
foreach k,v in (d){print(k,":",v,"; ")}</syntaxhighlight>
{{out}}
<pre>
A,B,C,D,
L("ALPHA","BETA","GAMMA","DELTA")
A:alpha; B:beta; C:gamma; D:delta;
</pre>
{{omit from|Applesoft BASIC}}
{{omit from|Brainf***}}
{{omit from|Commodore BASIC}}
{{omit from|Integer BASIC}}
{{omit from|TI-89 BASIC}} <!-- No builtin assoc arrays, would not be enlightening to show a defn -->
| |||