Hash from two arrays

Hash from two arrays
You are encouraged to solve this task according to the task description, using any language you may know.

Using two Arrays of equal length, create a Hash object where the elements from one array (the keys) are linked to the elements of the other (the values)

Related task: Associative arrays/Creation

ActionScript

package
{
    public class MyClass
    {
        public static function main():Void
        {
            var hash:Object = new Object();
            var keys:Array = new Array("a", "b", "c");
            var values:Array = new Array(1, 2, 3);
 
            for (var i:int = 0; i < keys.length(); i++)
                hash[keys[i]] = values[i]; 
        }
    }
}

Ada

Works with: GNAT version GPL 2007

with Ada.Strings.Hash;
with Ada.Containers.Hashed_Maps;
with Ada.Text_Io;
with Ada.Strings.Unbounded; use Ada.Strings.Unbounded;
 
procedure Hash_Map_Test is
   function Equivalent_Key (Left, Right : Unbounded_String) return Boolean is
   begin
      return Left = Right;
   end Equivalent_Key;
 
   function Hash_Func(Key : Unbounded_String) return Ada.Containers.Hash_Type is
   begin
      return Ada.Strings.Hash(To_String(Key));
   end Hash_Func;
 
   package My_Hash is new Ada.Containers.Hashed_Maps(Key_Type => Unbounded_String,
      Element_Type => Unbounded_String,
      Hash => Hash_Func,
      Equivalent_Keys => Equivalent_Key);
 
   type String_Array is array(Positive range <>) of Unbounded_String;
 
   Hash : My_Hash.Map;
   Key_List : String_Array := (To_Unbounded_String("foo"), 
      To_Unbounded_String("bar"),
      To_Unbounded_String("val"));
 
   Element_List : String_Array := (To_Unbounded_String("little"), 
      To_Unbounded_String("miss"), 
      To_Unbounded_String("muffet"));
 
begin
   for I in Key_List'range loop
      Hash.Insert(Key => (Key_List(I)),
         New_Item => (Element_List(I)));
   end loop;
   for I in Key_List'range loop
      Ada.Text_Io.Put_Line(To_String(Key_List(I)) & " => " &
         To_String(Hash.Element(Key_List(I))));
   end loop;
 
end Hash_Map_Test;

Argile

Works with: Argile version 1.1.0

use std, array, hash
 
let keys = @["hexadecimal" "decimal" "octal" "binary"]
let values = @[0xa 11 014 0b1101] (: 10 11 12 13 :)
let hash = new hash of int
for each val int i from 0 to 3
  hash[keys[i]] = values[i]
del hash hash

AutoHotkey

array1 := ["two", "three", "apple"]
array2 := [2, 3, "fruit"]
hash := {}
Loop % array1.maxIndex()
   hash[array1[A_Index]] := array2[A_Index]
MsgBox % hash["apple"] "`n" hash["two"]

AWK

Awk arrays are used for both lists and hash maps.

$ awk 'BEGIN{split("one two three",a);
             split("1 2 3",b);
             for(i=1;i in a;i++){c[a[i]]=b[i]};
             for(i in c)print i,c[i]
             }'
three 3
two 2
one 1

BASIC256

Solution is at Associative_array/Creation#BASIC256.

BBC BASIC

Works with: BBC BASIC for Windows

      DIM array1$(4) : array1$() = "0", "1", "2", "3", "4"
      DIM array2$(4) : array2$() = "zero", "one", "two", "three", "four"
 
      FOR index% = 0 TO DIM(array1$(),1)
        PROCputdict(mydict$, array2$(index%), array1$(index%))
      NEXT
      PRINT FNgetdict(mydict$, "3")
      END
 
      DEF PROCputdict(RETURN dict$, value$, key$)
      IF dict$ = "" dict$ = CHR$(0)
      dict$ += key$ + CHR$(1) + value$ + CHR$(0)
      ENDPROC
 
      DEF FNgetdict(dict$, key$)
      LOCAL I%, J%
      I% = INSTR(dict$, CHR$(0) + key$ + CHR$(1))
      IF I% = 0 THEN = "" ELSE I% += LEN(key$) + 2
      J% = INSTR(dict$, CHR$(0), I%)
      = MID$(dict$, I%, J% - I%)

Bracmat

  two three apple:?arr1
& 2 3 fruit:?arr2
& new$hash:?H
&   whl
  ' ( !arr1:%?k ?arr1
    & !arr2:%?v ?arr2
    & (H..insert)$(!k.!v)
    )
& (H..forall)$out
& ;
 

Output:

apple.fruit
three.3
two.2

Brat

zip = { keys, values |
	h = [:]
	keys.each_with_index { key, index |
		h[key] = values[index]
	}
 
	h
}
 
p zip [1 2 3] [:a :b :c]  #Prints [1: a, 2: b, 3: c]

C

There likely exist libraries that can be used for creating hashes that are better than the following implementation. There are also better functions for obtaining hash values from strings. The following implementation tries to be somewhat generic to facilitate using alternative key and value types.

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
 
#define KeyType const char *
#define ValType int
 
#define HASH_SIZE 4096
 
// hash function useful when KeyType is char * (string)
unsigned strhashkey( const char * key, int max)
{
    unsigned h=0;
    unsigned hl, hr;
 
    while(*key) {
        h += *key;
        hl= 0x5C5 ^ (h&0xfff00000 )>>18;
        hr =(h&0x000fffff );
        h = hl ^ hr ^ *key++;
    }
    return h % max;
}
 
typedef struct sHme {
    KeyType    key;
    ValType    value;
    struct sHme  *link;
} *MapEntry;
 
typedef struct he {
    MapEntry  first, last;
} HashElement;
 
HashElement hash[HASH_SIZE];
 
typedef void (*KeyCopyF)(KeyType *kdest, KeyType ksrc);
typedef void (*ValCopyF)(ValType *vdest, ValType vsrc);
typedef unsigned (*KeyHashF)( KeyType key, int upperBound );
typedef int (*KeyCmprF)(KeyType key1, KeyType key2);
 
void HashAddH( KeyType key, ValType value,
        KeyCopyF copyKey, ValCopyF copyVal, KeyHashF hashKey, KeyCmprF keySame )
{
    unsigned hix = (*hashKey)(key, HASH_SIZE);
    MapEntry m_ent;
 
    for (m_ent= hash[hix].first;
            m_ent && !(*keySame)(m_ent->key,key); m_ent=m_ent->link);
    if (m_ent) {
        (*copyVal)(&m_ent->value, value);
    }
    else {
        MapEntry last;
        MapEntry hme = malloc(sizeof(struct sHme));
        (*copyKey)(&hme->key, key);
        (*copyVal)(&hme->value, value);
        hme->link = NULL;
        last = hash[hix].last;
        if (last) {
//	    printf("Dup. hash key\n");
            last->link = hme;
        }
        else
            hash[hix].first = hme;
        hash[hix].last = hme;
    }
}
 
int HashGetH(ValType *val, KeyType key, KeyHashF hashKey, KeyCmprF keySame )
{
    unsigned hix = (*hashKey)(key, HASH_SIZE);
    MapEntry m_ent;
    for (m_ent= hash[hix].first;
            m_ent && !(*keySame)(m_ent->key,key); m_ent=m_ent->link);
    if (m_ent) {
        *val = m_ent->value;
    }
    return (m_ent != NULL);
}
 
void copyStr(const char**dest, const char *src)
{
    *dest = strdup(src);
}
void copyInt( int *dest, int src)
{
    *dest = src;
}
int strCompare( const char *key1, const char *key2)
{
    return strcmp(key1, key2) == 0;
}
 
void HashAdd( KeyType key, ValType value )
{
    HashAddH( key, value, &copyStr, &copyInt, &strhashkey, &strCompare);
}
 
int HashGet(ValType *val, KeyType key)
{
    return HashGetH( val, key, &strhashkey, &strCompare);
}
 
int main() 
{
    static const char * keyList[] = {"red","orange","yellow","green", "blue", "violet" };
    static int valuList[] = {1,43,640, 747, 42, 42};
    int ix;
 
    for (ix=0; ix<6; ix++) {
        HashAdd(keyList[ix], valuList[ix]);
    }
    return 0;
}

C++

Technically a std::map is a binary search tree, not a hash table, but it provides the same functionality. The C++11 standard incorporates hash tables. To use a hash table in C++11, simply change std::map to std::unordered_map. The core idea, turning two sequences into an associative mapping, is valid either way.

#include <map>
#include <string>
 
int
main( int argc, char* argv[] )
{
 std::string keys[] = { "1", "2", "3" } ;
 std::string vals[] = { "a", "b", "c" } ;
 
 std::map< std::string, std::string > hash ;
 
 for( int i = 0 ; i < 3 ; i++ )
 {
  hash[ keys[i] ] = vals[i] ;
 }
}

Alternatively:

#include <map>       // for std::map
#include <algorithm> // for std::transform
#include <string>    // for std::string
#include <utility>   // for std::make_pair
 
int main()
{
  std::string keys[] = { "one", "two", "three" };
  std::string vals[] = { "foo", "bar", "baz" };
 
  std::map<std::string, std::string> hash;
 
  std::transform(keys, keys+3,
                 vals,
                 std::inserter(hash, hash.end()),
                 std::make_pair<std::string, std::string>);
}

C#

System.Collections.HashTable h = new System.Collections.HashTable();
 
string[] arg_keys = {"foo","bar","val"};
string[] arg_values = {"little", "miss", "muffet"};
 
//Some basic error checking
int arg_length = 0;
if ( arg_keys.Length == arg_values.Length ) {
  arg_length = arg_keys.Length;
}
 
for( int i = 0; i < arg_length; i++ ){
  h.add( arg_keys[i], arg_values[i] ); 
}

Alternate way of adding values

for( int i = 0; i < arg_length; i++ ){
  h[ arg_keys[i] ] = arg_values[i]; 
}

Clojure

(zipmap [\a \b \c] [1 2 3])

CoffeeScript

 
  keys = ['a','b','c']
  values = [1,2,3]
  map = {}
  map[key] = values[i] for key, i in keys
 

ColdFusion

<cfscript>
function makeHash(keyArray, valueArray) {
  var x = 1;
  var result = {};
  for( ; x <= ArrayLen(keyArray); x ++ ) {
    result[keyArray[x]] = valueArray[x];
  }
  return result;
}
 
keyArray = ['a', 'b', 'c'];
valueArray = [1, 2, 3];
map = makeHash(keyArray, valueArray);
</cfscript>

Common Lisp

(defun rosetta-code-hash-from-two-arrays (vector-1 vector-2 &key (test 'eql))
  (assert (= (length vector-1) (length vector-2)))
  (let ((table (make-hash-table :test test :size (length vector-1))))
    (map nil (lambda (k v) (setf (gethash k table) v))
             vector-1 vector-2)
    table))

Or, using cl:loop:

(defun rosetta-code-hash-from-two-arrays (vector-1 vector-2 &key (test 'eql))
  (loop initially (assert (= (length vector-1) (length vector-2)))
        with table = (make-hash-table :test test :size (length vector-1))
        for k across vector-1
        for v across vector-2
        do (setf (gethash k table) v)
        finally (return table)))

In Common Lisp terminology, a vector is a one-dimensional array.

D

import std.array, std.range;
 
void main() {
    auto hash = ["a", "b", "c"].zip([1, 2, 3]).assocArray;
}

E

def keys := ["one", "two", "three"]
def values := [1, 2, 3]
__makeMap.fromColumns(keys, values)

F#

HashMultiMap(Array.zip [|"foo"; "bar"; "baz"|] [|16384; 32768; 65536|], HashIdentity.Structural)

Factor

USING: hashtables ;
{ "one" "two" "three" } { 1 2 3 } zip >hashtable

Falcon

 
keys = [ 'a', 'b', 'c', 'd' ]
values = [ 1, 2, 3, 4 ]
hash = [ => ]
for i in [ 0 : keys.len() ]:  hash[ keys[ i ] ] = values[ i ]
 

Fantom

 
class Main
{
  public static Void main ()
  {
    keys := [1,2,3,4,5]
    values := ["one", "two", "three", "four", "five"]
 
    // create an empty map
    map := [:]  
    // add the key-value pairs to it
    keys.size.times |Int index|
    {
      map.add(keys[index], values[index])
    }
  }
}
 

Go

package main
 
import "fmt"
 
func main() {
    keys := []string{"a", "b", "c"}
    vals := []int{1, 2, 3}
    hash := map[string]int{}
    for i, key := range keys {
        hash[key] = vals[i]
    }
    fmt.Println(hash)
}

Output:

map[b:2 a:1 c:3]

Groovy

keys = ['a','b','c']
vals = ['aaa', 'bbb', 'ccc']
hash = [:]
keys.eachWithIndex { key, i ->
 hash[key] = vals[i] 
}

Haskell

Works with: GHCi version 6.6

import Data.Map
 
makeMap ks vs = fromList $ zip ks vs
mymap = makeMap ['a','b','c'] [1,2,3]

Icon and Unicon

link ximage    # to format the structure
 
procedure main(arglist)                          #: demonstrate hash from 2 lists
local keylist 
 
if *arglist = 0 then arglist := [1,2,3,4]        # ensure there's a list
every put(keylist := [], "key-" || !arglist)     # make keys for each entry
 
every  (T := table())[keylist[ i := 1 to *keylist ]] := arglist[i]  # create the hash table
 
write(ximage(T))                                 # show result
end

Ioke

{} addKeysAndValues([:a, :b, :c], [1, 2, 3])

J

Solution:

hash=: vals {~ keys&i.

For example:

   keys=: 10?.100 
   vals=: > ;:'zero one two three four five six seven eight nine'
   hash=: vals {~ keys&i.
 
   keys
46 99 23 62 42 44 12 5 68 63
   $vals
10 5
 
   hash 46
zero 
   hash 99
one  
   hash 63 5 12 5 23
nine 
seven
six  
seven
two

Here, keys is a list of 10 integers between 0 and 99 chosen at random without repetition, and vals is a 10 by 5 character matrix.

Java

import java.util.HashMap;
public static void main(String[] args){
	String[] keys= {"a", "b", "c"};
	int[] vals= {1, 2, 3};
	HashMap<String, Integer> hash= new HashMap<String, Integer>();
 
	for(int i= 0; i < keys.length; i++){
	   hash.put(keys[i], vals[i]);
	}
}

JavaScript

var keys = ['a', 'b', 'c'];
var values = [1, 2, 3];
var map = {};
for(var i in keys) {
  map[ keys[i] ] = values[i];
}

K

The keys in a dictionary must be a symbol.

   a: `zero `one `two  / symbols
   b: 0 1 2
 
   d:. a,'b  / create the dictionary
.((`zero;0;)
  (`one;1;)
  (`two;2;))
 
   d[`one]
1

Here we use integers as keys (which must be converted to symbols) and strings as values (here also converted to symbols).

   keys: !10   / 0..9
   split:{1_'(&x=y)_ x:y,x}
   vals:split["zero one two three four five six seven eight nine";" "]
 
   s:{`$$x}  / convert to symbol
   d:. (s'keys),'s'vals
.((`"0";`zero;)
  (`"1";`one;)
  (`"2";`two;)
  (`"3";`three;)
  (`"4";`four;)
  (`"5";`five;)
  (`"6";`six;)
  (`"7";`seven;)
  (`"8";`eight;)
  (`"9";`nine;))
 
   $d[s 1] / leading "$" converts back to string
"one"

Lang5

: >table  2 compress -1 transpose ;
['one 'two 'three 'four] [1 2 3 4] >table

Lua

 
function(keys,values)
  local t = {}
  for i=1, #keys do
    t[keys[i]] = values[i]
  end
end
 

Mathematica

Map[(Hash[Part[#, 1]] = Part[#, 2]) &,
 Transpose[{{1, 2, 3}, {"one", "two", "three"}}]]
 
?? Hash 
->Hash[1]=one
->Hash[2]=two
->Hash[3]=three

NetRexx

REXX Style

Translation of: REXX

/* NetRexx program ****************************************************
* 04.11.2012 Walter Pachl  derived from REXX
**********************************************************************/
options replace format comments java crossref savelog symbols nobinary
  values='triangle quadrilateral pentagon hexagon heptagon octagon' -
         'nonagon decagon dodecagon'
  keys  ='three four five six seven eight nine ten twelve'
  kcopy=keys
  k=''                                 /* initialize the arrays      */
  v=''
  value='unknown'
  Loop i=1 By 1 While kcopy>''         /* initialize the two arrays  */
    Parse kcopy  ki kcopy;  k[i]=ki
    Parse values vi values; v[i]=vi
    End
  Loop j=1 To i-1
    value[k[j]]=v[j]
    End
  Say 'Enter one of these words:'
  Say ' 'keys
  Parse Ask z
  Say z '->' value[z]

Java Collections

NetRexx has access to Java's Collection objects too.

/* NetRexx */
options replace format comments java crossref symbols nobinary
 
vals = [ 'zero', 'one', 'two', 'three', 'four', 'five' ]
keys = [ 'k0', 'k1', 'k2', 'k3', 'k4', 'k5' ]
hash1 = Rexx
hash2 = Map
 
hash1 = HashMap()
hash2 = ''
makeHash(hash1, keys, vals) -- using a Map object (overloaded method)
makeHash(hash2, keys, vals) -- using a Rexx object (overloaded method)
 
return
 
-- Using a Java collection object
method makeHash(hash = Map, keys = Rexx[], vals = Rexx[]) static
  loop k_ = 0 to keys.length - 1
    hash.put(keys[k_], vals[k_])
    end k_
 
  key = Rexx
  loop key over hash.keySet()
    say key.right(8)':' hash.get(key)
    end key
  say
 
  return
 
-- For good measure a version using the default Rexx object as a hash (associative array)
method makeHash(hash = Rexx, keys = Rexx[], vals = Rexx[]) static
  loop k_ = 0 to keys.length - 1
    hash[keys[k_]] = vals[k_]
    end k_
 
  loop key over hash
    say key.right(8)':' hash[key]
    end key
  say
 
  return
 

Nemerle

using System;
using System.Console;
using Nemerle.Collections;
using Nemerle.Collections.NCollectionsExtensions;
 
module AssocArray
{
    Main() : void
    {
        def list1 = ["apples", "oranges", "bananas", "kumquats"];
        def list2 = [13, 34, 12];
        def inventory = Hashtable(ZipLazy(list1, list2));
        foreach (item in inventory)
            WriteLine("{0}:   {1}", item.Key, item.Value);
    }
}

Objeck

 
use Structure;
 
bundle Default {
  class HashOfTwo {
    function : Main(args : System.String[]) ~ Nil {
      keys := ["1", "2", "3"];
      vals := ["a", "b", "c"];
      hash := StringHash->New();
      each(i : vals) {
        hash->Insert(keys[i], vals[i]->As(Base));
      };
    }
  }
}
 

Objective-C

NSArray *keys = [NSArray arrayWithObjects:@"a", @"b", @"c", nil];
NSArray *values = [NSArray arrayWithObjects:[NSNumber numberWithInt:1],
                                            [NSNumber numberWithInt:2],
                                            [NSNumber numberWithInt:3], nil];
NSDictionary *dict = [NSDictionary dictionaryWithObjects:values forKeys:keys];

OCaml

The idiomatic solution uses lists rather than arrays.

let keys = [ "foo"; "bar"; "baz" ]
and vals = [ 16384; 32768; 65536 ]
and hash = Hashtbl.create 0;;
 
List.iter2 (Hashtbl.add hash) keys vals;;

In the extremely unlikely event that it was actually necessary to use arrays, the solution would become slightly less elegant: (except using the ExtLib which provides the equivalent Array.iter2)

let keys = [| "foo"; "bar"; "baz" |]
and vals = [| 16384; 32768; 65536 |]
and hash = Hashtbl.create 0;;
 
for i = 0 to Array.length keys - 1 do
  Hashtbl.add hash keys.(i) vals.(i)
done;;

In either case, an exception is raised if the inputs are different lengths.

If you want to use functional binary search trees instead of hash tables:

module StringMap = Map.Make (String);;
 
let keys = [ "foo"; "bar"; "baz" ]
and vals = [ 16384; 32768; 65536 ]
and map = StringMap.empty;;
 
let map = List.fold_right2 StringMap.add keys vals map;;

ooRexx

 
array1 = .array~of("Rick", "Mike", "David")
array2 = .array~of("555-9862", "555-5309", "555-6666")
 
-- if the index items are constrained to string objects, this can
-- be a directory too.
hash = .table~new
 
loop i = 1 to array1~size
    hash[array1[i]] = array2[i]
end
 

Oz

declare
  fun {ZipRecord Keys Values}
     {List.toRecord unit {List.zip Keys Values MakePair}}
  end
 
  fun {MakePair A B}
     A#B
  end
in
  {Show {ZipRecord [a b c] [1 2 3]}}

Pascal

Works with: Free_Pascal

Library: contnrs

program HashFromTwoArrays (Output);
 
uses
  contnrs;
 
var
  keys:   array[1..3] of string  = ('a', 'b', 'c');
  values: array[1..3] of integer = ( 1,   2,   3 );
  hash:   TFPDataHashTable;
  i:      integer;
 
begin
  hash := TFPDataHashTable.Create;
  for i := low(keys) to high(keys) do
    hash.add(keys[i], @values[i]);
  writeln ('Length of hash table: ', hash.Count);
  hash.Destroy;
end.

Output:

% ./HashFromTwoArrays
Length of hash table: 3

Perl

my @keys = qw(a b c);
my @vals = (1, 2, 3);
my %hash;
@hash{@keys} = @vals;

Alternatively, using

Library: List::MoreUtilsMoreUtils

:

use List::MoreUtils qw(zip);
my %hash = zip @keys, @vals;

Perl 6

Works with: Rakudo version #23 "Lisbon"

my @keys = <a b c d e>;
my @vals = ^5;
my %hash = @keys Z @vals;

or just

my @v = <a b c d e>;
my %hash = @v Z @v.keys;

Alternatively:

my %hash;
%hash{@keys} = @vals;

To create an anonymous hash value, you can use Z as a "zipwith" metaoperator on the => pair composer:

{ <a b c d e> Z=> ^5 }

PHP

Works with: PHP version 5

$keys = array('a', 'b', 'c');
$values = array(1, 2, 3);
$hash = array_combine($keys, $values);

Works with: PHP version 4

$keys = array('a', 'b', 'c');
$values = array(1, 2, 3);
$hash = array();
for ($idx = 0; $idx < count($keys); $idx++) {
  $hash[$keys[$idx]] = $values[$idx];
}

PicoLisp

(let (Keys '(one two three)  Values (1 2 3))
   (mapc println
      (mapcar cons Keys Values) ) )

Output:

(one . 1)
(two . 2)
(three . 3)

Pop11

vars keys = { 1 a b c};
vars vals = { 2 3 valb valc};
vars i;
;;; Create hash table
vars ht = newmapping([], 500, 0, true);
;;; Loop over input arrays (vectors)
for i from 1 to length(keys) do
  vals(i) -> ht(keys(i));
endfor;

PostScript

Library: initlib

 
% push our arrays
 [/a /b /c /d /e] [1 2 3 4 5] 
% create a dict with it
{aload pop} dip let currentdict end
% show that we have created the hash
 {= =} forall
 

PowerShell

function create_hash ([array] $keys, [array] $values) {
    $h = @{}
    if ($keys.Length -ne $values.Length) {
        Write-Error -Message "Array lengths do not match" `
                    -Category InvalidData `
                    -TargetObject $values
    } else {
        for ($i = 0; $i -lt $keys.Length; $i++) {
            $h[$keys[$i]] = $values[$i]
        }
    }
    return $h
}

Prolog

% this one with side effect hash table creation
 
:-dynamic hash/2.
 
make_hash([],[]).
make_hash([H|Q],[H1|Q1]):-
	assert(hash(H,H1)),
	make_hash(Q,Q1).
 
:-make_hash([un,deux,trois],[[a,b,c],[d,e,f],[g,h,i]])
 
 
% this one without side effects 
 
make_hash_pure([],[],[]).
make_hash_pure([H|Q],[H1|Q1],[hash(H,H1)|R]):-
	make_hash_pure(Q,Q1,R).
 
:-make_hash_pure([un,deux,trois],[[a,b,c],[d,e,f],[g,h,i]],L),findall(M,(member(M,L),assert(M)),L).

PureBasic

Dim keys.s(3)
Dim vals.s(3)
NewMap Hash.s()
 
keys(0)="a" : keys(1)="b" : keys(2)="c" : keys(3)="d" 
vals(0)="1" : vals(1)="2" : vals(2)="3" : vals(3)="4" 
For n = 0 To 3
    Hash(keys(n))= vals(n)
Next
ForEach Hash()
   Debug Hash()
Next

Python

Works with: Python version 3.0+ and 2.7

Shows off the dict comprehensions in Python 3 (that were back-ported to 2.7):

keys = ['a', 'b', 'c']
values = [1, 2, 3]
hash = {key: value for key, value in zip(keys, values)}

Works with: Python version 2.2+

keys = ['a', 'b', 'c']
values = [1, 2, 3]
hash = dict(zip(keys, values))
 
# Lazily, Python 2.3+, not 3.x:
from itertools import izip
hash = dict(izip(keys, values))

Works with: Python version 2.0+

keys = ['a', 'b', 'c']
values = [1, 2, 3]
hash = {}
for k,v in zip(keys, values):
    hash[k] = v

The original (Ruby) example uses a range of different types as keys. Here is similar in python (run at the shell):

>>> class Hashable(object):
	def __hash__(self):
		return id(self) ^ 0xBEEF
 
 
>>> my_inst = Hashable()
>>> my_int = 1
>>> my_complex = 0 + 1j
>>> my_float = 1.2
>>> my_string = "Spam"
>>> my_bool = True
>>> my_unicode = u'Ham'
>>> my_list = ['a', 7]
>>> my_tuple = ( 0.0, 1.4 )
>>> my_set = set(my_list)
>>> def my_func():
	pass
 
>>> class my_class(object):
	pass
 
>>> keys = [my_inst, my_tuple, my_int, my_complex, my_float, my_string,
	my_bool, my_unicode, frozenset(my_set), tuple(my_list),
	my_func, my_class]
>>> values = range(12)
>>> d = dict(zip(keys, values))
>>> for key, value in d.items(): print key, ":", value
 
1 : 6
1j : 3
Ham : 7
Spam : 5
(0.0, 1.3999999999999999) : 1
frozenset(['a', 7]) : 8
1.2 : 4
('a', 7) : 9
<function my_func at 0x0128E7B0> : 10
<class '__main__.my_class'> : 11
<__main__.Hashable object at 0x012AFC50> : 0
>>> # Notice that the key "True" disappeared, and its value got associated with the key "1"
>>> # This is because 1 == True in Python, and dictionaries cannot have two equal keys

R

Assuming that the keys are coercible to character form, we can simply use the names attribute to create a hash. This example is taken from the Wikipedia page on hash tables.

# Set up hash table
keys <- c("John Smith", "Lisa Smith", "Sam Doe", "Sandra Dee", "Ted Baker")
values <- c(152, 1, 254, 152, 153)
names(values) <- keys
# Get value corresponding to a key
values["Sam Doe"]                          # vals["Sam Doe"]
# Get all keys corresponding to a value
names(values)[values==152]                 # "John Smith" "Sandra Dee"

Racket

 
(make-hash (map cons '("a" "b" "c" "d") '(1 2 3 4)))

Alternatively:

 
(define (connect keys vals)  (for/hash ([k keys] [v vals]) (values k v)))
;; Example:
(connect #("a" "b" "c" "d") #(1 2 3 4))
 

Raven

[ 'a' 'b' 'c' ] as $keys [ 1 2 3 ] as $vals
$keys $vals combine as $hash

REXX

/*REXX program demonstrate  hashing  of a  stemmed array  (from a key). */
                                       /*names of the 9 regular polygons*/
values='triangle quadrilateral pentagon hexagon heptagon octagon nonagon decagon dodecagon'
keys  ='thuhree  vour          phive    sicks   zeaven   ate     nein    den     duzun'
 
/*superflous blanks added to humorous keys just 'cause it looks prettier*/
call hash values,keys                  /*hash the keys to the values.   */
parse arg query .                      /*what was specified on cmd line.*/
if query==''  then exit                /*nothing, then let's leave Dodge*/
pad=left('',30)                        /*used for padding the display.  */
say 'key:' query  pad  "value:"  hash.query    /*show & tell some stuff.*/
exit                                   /*stick a fork in it, we're done.*/
/*──────────────────────────────────HASH subroutine─────────────────────*/
hash: procedure expose hash.;   parse arg v,k,hash.
            do j=1  until map='';        map=word(k,j)
                                    hash.map=word(v,j)
            end   /*j*/
return

output when using the input of: phive

key: phive                                value: pentagon

Ruby

 
keys=['hal',666,[1,2,3]]
vals=['ibm','devil',123]
 
if RUBY_VERSION >= '1.8.7'
  # Easy way, but needs Ruby 1.8.7 or later.
  hash = Hash[keys.zip(vals)]
else
  hash = keys.zip(vals).inject({}) {|h, kv| h.store(*kv); h }
end
 
p hash  # => {"hal"=>"ibm", 666=>"devil", [1, 2, 3]=>123}
 
#retrieve the value linked to the key [1,2,3]
puts hash[ [1,2,3] ]  # => 123
 

Or define a new method in class Array:

 
class Array
  def zip_hash(other)
    Hash[self.zip(other)]
  end
end
 
hash = %w{ a b c }.zip_hash( %w{ 1 2 3 } )
p hash  # => {"a"=>"1", "b"=>"2", "c"=>"3"}
 

Hash[] is calling "to_hash" inside. Therefore, it doesn't work out when making a method name "to_hash".

Sather

class ZIPPER{K,E} is
  zip(k:ARRAY{K}, e:ARRAY{E}) :MAP{K, E} 
    pre k.size = e.size
  is
    m :MAP{K, E} := #;
    loop m[k.elt!] := e.elt!; end;
    return m;    
  end;
end;
 
class MAIN is
 
  main is
    keys:ARRAY{STR} := |"one", "three", "four"|;
    values:ARRAY{INT} := |1, 3, 4|;
    m ::= ZIPPER{STR,INT}::zip(keys, values);
    loop 
      #OUT + m.pair! + " "; 
    end;
    #OUT + "\n";
  end;
 
end;

Scala

val keys = Array(1, 2, 3)
val values = Array("A", "B", "C")
val map = keys.zip(values).toMap

Scheme

Using SRFI 69:

(define (lists->hash-table keys values . rest)
  (apply alist->hash-table (map cons keys values) rest))

Seed7

$ include "seed7_05.s7i";
 
const type: numericHash is hash [string] integer;
var numericHash: myHash is numericHash.value;
 
const proc: main is func
  local
    var array string: keyList is [] ("one", "two", "three");
    var array integer: valueList is [] (1, 2, 3);
    var integer: number is 0;
  begin
    for number range 1 to length(keyList) do
      myHash @:= [keyList[number]] valueList[number];
    end for;
  end func;

Smalltalk

Works with: GNU Smalltalk

Array extend [
  dictionaryWithValues: array [ |d|
    d := Dictionary new.
    1 to: ((self size) min: (array size)) do: [:i|
      d at: (self at: i) put: (array at: i).
    ].
    ^ d
  ]
].
 
 
({ 'red' . 'one' . 'two' } 
 dictionaryWithValues: { '#ff0000'. 1. 2 }) displayNl.

Works with: Smalltalk/X

Works with: VisualWorks Smalltalk

Dictionary 
    withKeys:#('one' 'two' 'three')
    andValues:#('eins' 'zwei' 'drei')

Works with: Smalltalk/X

Dictionary withAssociations:{ 'one'->1 . 'two'->2 . 'three'->3 }

SNOBOL4

Works with: Macro Spitbol

Works with: Snobol4+

Works with: CSnobol

*       # Fill arrays
        keys = array(5); vals = array(5)
        ks = 'ABCDE'; vs = '12345'
kloop   i = i + 1; ks len(1) . keys<i> = :s(kloop)
vloop   j = j + 1; vs len(1) . vals<j> = :s(vloop)
 
*       # Create hash
        hash = table(5)
hloop   k = k + 1; hash<keys<k>> = vals<k> :s(hloop)
 
*       # Test and display
        ts = 'ABCDE'
tloop   ts len(1) . ch = :f(out)
        str = str ch ':' hash<ch> ' ' :(tloop)
out     output = str
end

Output:

A:1 B:2 C:3 D:4 E:5

Standard ML

Works with: SML/NJ

Using functional binary search trees instead of hash tables:

structure StringMap = BinaryMapFn (struct
                                     type ord_key = string
                                     val compare = String.compare
                                   end);
 
val keys = [ "foo", "bar", "baz" ]
and vals = [ 16384, 32768, 65536 ]
and myMap = StringMap.empty;
 
val myMap = foldl StringMap.insert' myMap (ListPair.zipEq (keys, vals));

Works with: SML/NJ

Using hash tables:

exception NotFound;
 
val keys = [ "foo", "bar", "baz" ]
and vals = [ 16384, 32768, 65536 ]
and hash = HashTable.mkTable (HashString.hashString, op=) (42, NotFound);
 
ListPair.appEq (HashTable.insert hash) (keys, vals);

Tcl

Arrays in Tcl are automatically associative, i.e. there are no "not hashed arrays". If we can take "arrays of equal length" to mean "lists of equal length", then the task might look like this:

set keys [list fred bob joe]
set values [list barber plumber tailor]
array set arr {}
foreach a $keys b $values { set arr($a) $b }

Alternatively, a dictionary could be used:

foreach a $keys b $values {
    dict set jobs $a $b
}

TXR

@(do (defun hash-from-two (vec1 vec2 equal-based-p)
       (let ((table (make-hash nil nil equal-based-p)))
         (for ((i 0)) ((< i (length vec1)) table) ((inc i))
           (set (gethash table (vecref vec1 i) 0) 
                (vecref vec2 i))))))
@(bind hash @(hash-from-two #(a b c) #(1 2 3) nil))
@(bind (keys vals) @(let (k v)
                      (dohash (key val hash (list k v))
                        (push key k)
                        (push val v))))

$ ./txr rosetta/hash-from-two.txr 
hash="#<hash: 175bc40>"
keys[0]="a"
keys[1]="b"
keys[2]="c"
vals[0]="1"
vals[1]="2"
vals[2]="3"

UnixPipes

Using a sorted file as an associative array (see Creating an associative array for usage.)

cat <<VAL >p.values
apple
boy
cow
dog
elephant
VAL
 
cat <<KEYS >p.keys
a
b
c
d
e
KEYS
 
paste -d\   <(cat p.values | sort) <(cat p.keys | sort)

Ursala

There's a built in operator for this.

keys   = <'foo','bar','baz'>
values = <12354,145430,76748>
 
hash_function = keys-$values

test program:

#cast %nL
 
test = hash_function* <'bar','baz','foo','bar'>

output:

<145430,76748,12354,145430>

Vala

Library: Gee

 
using Gee;
 
void main(){
    // mostly copied from C# example                                            
    var hashmap = new HashMap<string, string>();
 
    string[] arg_keys = {"foo", "bar", "val"};
    string[] arg_values = {"little", "miss", "muffet"};
 
    if (arg_keys.length	== arg_values.length ){
	for (int i = 0;	i < arg_keys.length; i++){
            hashmap[arg_keys[i]] = arg_values[i];
	}
    }
}
 

VBScript

VBScript (and Visual Basic in general) calls hashes "dictionary objects".

Set dict = CreateObject("Scripting.Dictionary")
os = Array("Windows", "Linux", "MacOS")
owner = Array("Microsoft", "Linus Torvalds", "Apple")
For n = 0 To 2
    dict.Add os(n), owner(n)
Next
MsgBox dict.Item("Linux")
MsgBox dict.Item("MacOS")
MsgBox dict.Item("Windows")

Output (in message boxes):

Linus Torvalds
Apple
Microsoft

Visual Basic

Translation of: VBScript

The VBScript version can be used in Visual Basic unchanged, although it requires a reference to the Microsoft Scripting Runtime (scrrun.dll).

Alternately, instead of a Dictionary object, you can also use a Collection object, which serves a similar purpose, without the inclusion of an additional runtime library. In fact, the only immediately-obvious difference between this and the VBScript example is dict's data type, and the order that the arguments are passed to the Add method.

Dim dict As New Collection
os = Array("Windows", "Linux", "MacOS")
owner = Array("Microsoft", "Linus Torvalds", "Apple")
For n = 0 To 2
    dict.Add owner(n), os(n)
Next
Debug.Print dict.Item("Linux")
Debug.Print dict.Item("MacOS")
Debug.Print dict.Item("Windows")