Range extraction: Difference between revisions
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function rangeString(xs) { |
function rangeString(xs) { |
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var |
var iRightmost = xs.length - 1, |
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lstSeries = xs. |
lstSeries = xs.reduceRight(function (a, x, i, l) { |
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return i < iRightmost ? ( |
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// just an unmodified copy of the accumulator |
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(1 < dNext || null === dNext) ? ( |
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}, []); |
}, []); |
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}).join(','); |
}).join(','); |
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} |
} |
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return rangeString(lstTest); |
return rangeString(lstTest); |
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})([0, 1, 2, 4, 6, 7, 8, 11, 12, 14, |
})([0, 1, 2, 4, 6, 7, 8, 11, 12, 14, |
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Revision as of 16:59, 24 November 2015
You are encouraged to solve this task according to the task description, using any language you may know.
A format for expressing an ordered list of integers is to use a comma separated list of either
- individual integers
- Or a range of integers denoted by the starting integer separated from the end integer in the range by a dash, '-'. (The range includes all integers in the interval including both endpoints)
- The range syntax is to be used only for, and for every range that expands to more than two values.
Example
The list of integers:
- -6, -3, -2, -1, 0, 1, 3, 4, 5, 7, 8, 9, 10, 11, 14, 15, 17, 18, 19, 20
Is accurately expressed by the range expression:
- -6,-3-1,3-5,7-11,14,15,17-20
(And vice-versa).
The task
- Create a function that takes a list of integers in increasing order and returns a correctly formatted string in the range format.
- Use the function to compute and print the range formatted version of the following ordered list of integers. (The correct answer is:
0-2,4,6-8,11,12,14-25,27-33,35-39.)
0, 1, 2, 4, 6, 7, 8, 11, 12, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 27, 28, 29, 30, 31, 32, 33, 35, 36, 37, 38, 39
- Show the output of your program.
C.f. Range expansion
Ada
The provided solutions return an empty string, if the Sequence of integers is empty. Ranges with negative bounds are represented as -9--4, as the task requires. For real-life applications it is better to use the notation -9..-4.
Iterative Solution
Since we don't know in advance how long the output will be, the iterative solution uses Unbounded_Strings.
<lang Ada>with Ada.Text_IO; use Ada.Text_IO; with Ada.Strings.Unbounded; use Ada.Strings.Unbounded; with Ada.Strings.Fixed; use Ada.Strings.Fixed;
procedure Range_Extraction is
type Sequence is array (Positive range <>) of Integer;
function Image (S : Sequence) return String is
Result : Unbounded_String;
From : Integer;
procedure Flush (To : Integer) is
begin
if Length (Result) > 0 then
Append (Result, ',');
end if;
Append (Result, Trim (Integer'Image (From), Ada.Strings.Left));
if From < To then
if From+1 = To then
Append (Result, ',');
else
Append (Result, '-');
end if;
Append (Result, Trim (Integer'Image (To), Ada.Strings.Left));
end if;
end Flush;
begin
if S'Length > 0 then
From := S (S'First);
for I in S'First + 1..S'Last loop
if S (I - 1) + 1 /= S (I) then
Flush (S (I - 1));
From := S (I);
end if;
end loop;
Flush (S (S'Last));
end if;
return To_String (Result);
end Image;
begin
Put_Line
( Image
( ( 0, 1, 2, 4, 6, 7, 8, 11, 12, 14,
15, 16, 17, 18, 19, 20, 21, 22, 23, 24,
25, 27, 28, 29, 30, 31, 32, 33, 35, 36,
37, 38, 39
) ) );
end Range_Extraction;</lang>
Recursive Solution
The recursive solution avoids the usage of unbounded strings.
<lang Ada>with Ada.Text_IO, Ada.Strings.Fixed;
procedure Range_Extract is
type Sequence is array (Positive range <>) of Integer;
function Img(I: Integer) return String is -- the image of an Integer
begin
return
Ada.Strings.Fixed.Trim(Integer'Image(I), Ada.Strings.Left);
end Img;
function Img(S: Sequence) return String is -- the image of a Sequence
function X(S : Sequence) return String is -- recursive eXtract
Idx: Positive := S'First;
begin
if S'Length = 0 then return
""; -- return nothing if Sequence is empty
else
while Idx < S'Last and then S(Idx+1) = S(Idx) + 1 loop
Idx := Idx + 1;
end loop;
if Idx = S'First then return
"," & Img(S(Idx)) & X(S(Idx+1 .. S'Last));
elsif Idx = S'First+1 then return
"," & Img(S(S'First)) & ',' & Img(S(Idx)) & X(S(Idx+1 .. S'Last));
else return
"," & Img(S(S'First)) & '-' & Img(S(Idx)) & X(S(Idx+1 .. S'Last));
end if;
end if;
end X;
begin -- function Img(S: Sequence) return String
if S'Length = 0 then return
"";
else return
Img(S(S'First)) & X(S(S'First+1 .. S'Last));
end if;
end Img;
begin -- main
Ada.Text_IO.Put_Line(Img( ( 0, 1, 2, 4, 6, 7, 8, 11, 12, 14, 15, 16,
17, 18, 19, 20, 21, 22, 23, 24, 25, 27, 28, 29,
30, 31, 32, 33, 35, 36, 37, 38, 39) ));
end Range_Extract;</lang>
- Output:
The sample output is exactly the same, for both solutions:
0-2,4,6-8,11,12,14-25,27-33,35-39
Aime
<lang aime>text rp(...) {
integer i, j; data b; text f;
i = 0;
j = 0;
while (i < count()) {
while (j < count() - 1) {
if (__integer($(j + 1)) == __integer($j) + 1) {
j += 1;
} else {
break;
}
}
if (i + 1 < j) {
b_form(b, "%s%d-%d", f, $i, $j);
f = ",";
} else {
while (i < j + 1) {
b_form(b, "%s%d", f, $i);
f = ",";
i += 1;
}
}
j += 1; i = j;
}
return b_string(b);
}
integer main(void) {
o_form("%s\n", rp(0, 1, 2, 4, 6, 7, 8, 11, 12, 14, 15, 16, 17, 18, 19, 20,
21, 22, 23, 24, 25, 27, 28, 29, 30, 31, 32, 33, 35, 36,
37, 38, 39));
return 0;
}</lang>
- Output:
0-2,4,6-8,11,12,14-25,27-33,35-39
ALGOL 68
Note: The following Iterative code specimen is the "unrolled" version of the Generative code specimen below. Together they provided as a comparison of the two different methods.
Iterative
- The closest concept that Algol 68 has to duck typing is the tagged union. This is used to define mode urange = union(int, struct(int lwb, upb)). If duck typing was available it could reduced the size of the code specimen, but would have lost some of Algol 68's strong type data security.
File: Template_Range_extraction_Base.a68 <lang algol68>###
REQUIRES(MODE SCALAR, OP(SCALAR,SCALAR)BOOL =, OP(SCALAR,SCALAR)SCALAR +);
MODE SCALARLIST = FLEX[0]SCALAR; MODE YIELDINT = PROC(SCALAR)VOID;
- Declarations for manipulating lists of range pairs [lwb:upb] #
MODE RANGE = STRUCT(SCALAR lwb, upb); MODE RANGELIST = FLEX[0]RANGE; MODE YIELDRANGE = PROC(RANGE)VOID;
PROC range repr = (RANGE range)STRING: (
STRING lwb := whole(lwb OF range,0); IF lwb OF range = upb OF range THEN lwb ELSE # "["+lwb+":"+whole(upb OF range,0)+"]" # lwb+"-"+whole(upb OF range,0) FI
);
- OP REPR = (RANGE range)STRING: range repr(range); # # firmly related to UNIRANGE #
- Declarations for manipulating lists containing pairs AND lone INTs #
MODE UNIRANGE = UNION(SCALAR, RANGE); MODE UNIRANGELIST = FLEX[0]UNIRANGE; MODE YIELDUNIRANGE = PROC(UNIRANGE)VOID;
PROC unirange repr = (UNIRANGE unirange)STRING:
CASE unirange IN (RANGE range): range repr(range), (SCALAR scalar): whole(scalar,0) ESAC;
OP (UNIRANGE)STRING REPR = unirange repr; # alias #
- The closest thing Algol68 has to inheritance is the UNION #
MODE UNIRANGELISTS = UNION(UNIRANGELIST, RANGELIST, SCALARLIST);
PROC unirange list repr = (UNIRANGELIST unirange list)STRING: (
- Produce a STRING representation of a UNIRANGELIST ###
STRING out # := "("#, sep := "";
FOR key FROM LWB unirange list TO UPB unirange list DO
out +:= sep + REPR unirange list[key];
sep := "," # +" " #
OD;
out # +")" #
);
OP (UNIRANGELIST)STRING REPR = unirange list repr; # alias #</lang>File: Template_Range_extraction_Iterative.a68 <lang algol68>###
REQUIRES(MODE SCALAR, OP(SCALAR,SCALAR)BOOL =, OP(SCALAR,SCALAR)SCALAR +);
PR READ "Template_Range_extraction_Base.a68" PR
OP (UNIRANGELISTS)UNIRANGELIST INITUNIRANGE = init unirange list; # alias #
PROC init unirange list = (UNIRANGELISTS unirange list)UNIRANGELIST: (
- Take a []SCALAR, []RANGE or []UNIRANGE, and return a normalised []UNIRANGE ###
INT len = UPB unirange list-LWB unirange list+1; [LWB unirange list: LWB unirange list+len*2]UNIRANGE out unirange list; SCALAR upb out unirange list := LWB out unirange list - 1; UNION(VOID, RANGE) prev range := EMPTY;
PROC out unirange list append = (RANGE value)VOID:(
IF lwb OF value = upb OF value THEN
out unirange list[upb out unirange list+:=1] := lwb OF value
ELIF lwb OF value + 1 = upb OF value THEN
out unirange list[upb out unirange list+:=1] := lwb OF value;
out unirange list[upb out unirange list+:=1] := upb OF value
ELSE
out unirange list[upb out unirange list+:=1] := value
FI
);
FOR key FROM LWB unirange list TO UPB unirange list DO
UNIRANGE value = CASE unirange list IN
(SCALARLIST list):list[key],
(RANGELIST list):list[key],
(UNIRANGELIST list):list[key]
ESAC;
RANGE next range := CASE value IN
(RANGE range): range,
(SCALAR value): RANGE(value, value)
ESAC;
prev range :=
CASE prev range IN
(VOID): next range,
(RANGE prev range):
IF upb OF prev range + 1 = lwb OF next range THEN
RANGE(lwb OF prev range, upb OF next range) # merge the range #
ELSE
out unirange list append(prev range);
next range
FI
OUT SKIP
ESAC
OD;
CASE prev range IN (RANGE last range): out unirange list append(last range) ESAC;
out unirange list[:upb out unirange list]
);</lang>File: test_Range_extraction_Integer.a68<lang algol68>#!/usr/local/bin/a68g --script #
- some simple test cases: #
MODE SCALAR = INT; PR READ "Template_Range_extraction_Iterative.a68" PR
- PR READ "Template_Range_extraction_Generative.a68" PR#
MODE RANGEINT = UNIRANGE;
test: BEGIN
[]INT int list = ( # unnormalised # 0, 1, 2, 4, 6, 7, 8, 11, 12, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 27, 28, 29, 30, 31, 32, 33, 35, 36, 37, 38, 39);
[]RANGE range list = ( # unnormalised # (0,0), (1,1), (2,2), (4,4), (6,6), (7,7), (8,8), (11,11), (12,12), (14,14), (15,15), (16,16), (17,17), (18,18), (19,19), (20,20), (21,21), (22,22), (23,23), (24,24), (25,25), (27,27), (28,28), (29,29), (30,30), (31,31), (32,32), (33,33), (35,35), (36,36), (37,37), (38,38), (39,39));
[]RANGEINT list a = ( # unnormalised # RANGE(0,2), 4, RANGE(6,8), RANGE(11,12), RANGE(14,25), RANGE(27,33), RANGE(35,39));
[]RANGEINT list b = ( # unnormalised # 0, 1, 2, 4, 6, 7, 8, 11, 12, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 27, 28, 29, 30, 31, 32, 33, 35, 36, 37, 38, 39);
[]RANGEINT list c = INITUNIRANGE(list b); # normalised #
- compare manipulation of various types of argument lists #
printf(($gl$, REPR INITUNIRANGE int list, REPR INITUNIRANGE range list, REPR INITUNIRANGE list a, REPR INITUNIRANGE list b, REPR list c ))
END</lang>
- Output:
0-2,4,6-8,11,12,14-25,27-33,35-39 0-2,4,6-8,11,12,14-25,27-33,35-39 0-2,4,6-8,11,12,14-25,27-33,35-39 0-2,4,6-8,11,12,14-25,27-33,35-39 0-2,4,6-8,11,12,14-25,27-33,35-39
Generative
- The following code a set of helper functions/generators that can be used to manipulate a lists of ranges. They can manipulate either arrays or iterator. And they can handle data of type int or range and both these types unioned.
These chained iterators do the following steps:
- Iterate through three different types of initial arrays - []int, []range and []unirange with gen range, yielding range(lwb,upb)
- Iterate with gen range merge yielding merged range(lwb,upb)
- Iterate with gen unirange merge, merging and yielding a union of int and range
- Finally iterate with unirange list init exiting with an array of union of int and range.
File: Template_Range_extraction_Generative.a68 <lang algol68>###
REQUIRES(MODE SCALAR, OP(SCALAR,SCALAR)BOOL =, OP(SCALAR,SCALAR)SCALAR +);
PR READ "Template_Range_extraction_Base.a68" PR
PROC gen range = (UNIRANGELISTS unirange list, YIELDRANGE yield range)VOID:
- Take a []SCALAR, []RANGE or []URANGE, and generatively yield an unnormalised RANGE ###
FOR key FROM LWB unirange list TO UPB unirange list DO
- Note: Algol 68RS cannot handle LWB and UPB of a UNION in the following: #
UNIRANGE value = CASE unirange list IN
(SCALARLIST list):list[key],
(RANGELIST list):list[key],
(UNIRANGELIST list):list[key]
ESAC;
yield range(
CASE value IN
(RANGE range): range,
(SCALAR value): (value, value)
ESAC
)
OD;
PROC gen range merge = (UNIRANGELISTS unirange list, YIELDRANGE yield)VOID: (
- Take a []SCALAR, []RANGE or []URANGE , and generatively yield a normalised RANGE ###
UNION(VOID, RANGE) prev range := EMPTY;
- FOR RANGE next range IN # gen range(unirange list, # ) DO #
- (RANGE next range)VOID:
- if the ranges cannot be merge, then yield 1st, and return 2nd #
prev range :=
CASE prev range IN
(VOID): next range,
(RANGE prev range):
IF upb OF prev range + 1 = lwb OF next range THEN
RANGE(lwb OF prev range, upb OF next range) # merge the range #
ELSE
#IF lwb OF prev range <= upb OF prev range THEN#
yield(prev range);
#FI;#
next range
FI
OUT SKIP
ESAC
- OD # );
CASE prev range IN (RANGE last range): yield(last range) ESAC
);
PROC gen unirange merge = (UNIRANGELISTS unirange list, YIELDUNIRANGE yield)VOID: (
- Take a []SCALAR, []RANGE or []UNIRANGE and generatively yield a normalised UNIRANGE ###
PROC unpack = (RANGE value)VOID:(
IF lwb OF value = upb OF value THEN
yield(lwb OF value)
ELIF lwb OF value + 1 = upb OF value THEN
yield(lwb OF value);
yield(upb OF value)
ELSE
yield(value)
FI
);
gen range merge(unirange list, unpack)
);
PROC unirange list init = (UNIRANGELISTS unirange list)UNIRANGELIST: (
- Take a []SCALAR, []RANGE or []UNIRANGE and return a static []UNIRANGE ###
INT len = UPB unirange list - LWB unirange list + 1; [LWB unirange list: LWB unirange list + len * 2]UNIRANGE out unirange list; # estimate # SCALAR upb out unirange list := LWB out unirange list - 1;
- FOR UNIRANGE unirange IN # gen unirange merge(unirange list, # ) DO #
- (UNIRANGE unirange)VOID:
out unirange list[upb out unirange list+:=1] := unirange
- OD # );
out unirange list[:upb out unirange list]
);
OP (UNIRANGELISTS)UNIRANGELIST INITUNIRANGE = unirange list init; # alias #</lang>
- Output:
0-2,4,6-8,11,12,14-25,27-33,35-39 0-2,4,6-8,11,12,14-25,27-33,35-39 0-2,4,6-8,11,12,14-25,27-33,35-39 0-2,4,6-8,11,12,14-25,27-33,35-39 0-2,4,6-8,11,12,14-25,27-33,35-39
AutoHotkey
<lang AutoHotkey>msgbox % extract("0,1,2,4,6,7,8,11,12,14,15,16,17,18,19,20,21,22,23,24,25,27,28,29,30,31,32,33,35,36,37,38,39")
extract( list ) {
loop, parse, list, `,, %A_Tab%%A_Space%`r`n
{
if (A_LoopField+0 != p+1)
ret .= (f!=p ? (p>f+1 ? "-" : ",") p : "") "," f := A_LoopField
p := A_LoopField
}
return SubStr(ret (f!=p ? (p>f+1 ? "-" : ",") p : ""), 2)
}</lang>
- Output:
--------------------------- Range extraction.ahk --------------------------- 0-2,4,6-8,11,12,14-25,27-33,35-39 --------------------------- OK ---------------------------
AWK
AWK is a primitive bird that prefers global scope for arrays.
Local variables for functions are declared in the parameters and, by convention, separated from the expected ones by extra space.
<lang awk>#!/usr/bin/awk -f
BEGIN {
delete sequence delete range
seqStr = "0,1,2,4,6,7,8,11,12,14,15,16,17,18,19,20,21,22,23,24," seqStr = seqStr "25,27,28,29,30,31,32,33,35,36,37,38,39" print "Sequence: " seqStr fillSequence(seqStr) rangeExtract() showRange() exit
}
function rangeExtract( runStart, runLen) {
delete range
runStart = 1
while(runStart <= length(sequence)) {
runLen = getSeqRunLen(runStart)
addRange(runStart, runLen)
runStart += runLen
}
}
function getSeqRunLen(startPos, pos) {
for (pos = startPos; pos < length(sequence); pos++) {
if (sequence[pos] + 1 != sequence[pos + 1]) break;
}
return pos - startPos + 1;
}
function addRange(startPos, len, str) {
if (len == 1) str = sequence[startPos] else if (len == 2) str = sequence[startPos] "," sequence[startPos + 1] else str = sequence[startPos] "-" sequence[startPos + len - 1] range[length(range) + 1] = str
}
function showRange( r) {
printf " Ranges: "
for (r = 1; r <= length(range); r++) {
if (r > 1) printf ","
printf range[r]
}
printf "\n"
}
function fillSequence(seqStr, n, s) {
n = split(seqStr,a,/[,]+/)
for (s = 1; s <= n; s++) {
sequence[s] = a[s]
}
}</lang>
- Output:
Sequence: 0,1,2,4,6,7,8,11,12,14,15,16,17,18,19,20,21,22,23,24,25,27,28,29,30,31,32,33,35,36,37,38,39 Ranges: 0-2,4,6-8,11,12,14-25,27-33,35-39
BBC BASIC
<lang bbcbasic> range$ = " 0, 1, 2, 4, 6, 7, 8, 11, 12, 14, " + \
\ "15, 16, 17, 18, 19, 20, 21, 22, 23, 24, " + \
\ "25, 27, 28, 29, 30, 31, 32, 33, 35, 36, " + \
\ "37, 38, 39"
PRINT FNrangeextract(range$)
END
DEF FNrangeextract(r$)
LOCAL f%, i%, r%, t%, t$
f% = VAL(r$)
REPEAT
i% = INSTR(r$, ",", i%+1)
t% = VALMID$(r$, i%+1)
IF t% = f% + r% + 1 THEN
r% += 1
ELSE
CASE r% OF
WHEN 0: t$ += STR$(f%) + ","
WHEN 1: t$ += STR$(f%) + "," + STR$(f% + r%) + ","
OTHERWISE: t$ += STR$(f%) + "-" + STR$(f% + r%) + ","
ENDCASE
r% = 0
f% = t%
ENDIF
UNTIL i% = 0
= LEFT$(t$)</lang>
- Output:
0-2,4,6-8,11,12,14-25,27-33,35-39
Bracmat
<lang bracmat> ( rangeExtract
= accumulator firstInRange nextInRange
, accumulate fasten rangePattern
. ( accumulate
= !accumulator
(!accumulator:|?&",")
!firstInRange
( !firstInRange+1:<>!nextInRange
& ( !firstInRange+2:!nextInRange&","
| "-"
)
-1+!nextInRange
|
)
: ?accumulator
)
& ( fasten
= [%( !accumulate
& (!sjt:?firstInRange)+1:?nextInRange
)
)
& ( rangePattern
= (
| ?
( !nextInRange
& 1+!nextInRange:?nextInRange
)
)
( &!accumulate
| (#<>!nextInRange:!fasten) !rangePattern
)
)
& :?accumulator:?firstInRange
& !arg:(|#!fasten !rangePattern)
& str$!accumulator
)
& ( test
= L A
. put$(!arg " ==>\n",LIN)
& ( !arg:(?,?)
& whl'(!arg:(?A,?arg)&(!A,!L):?L)
& whl'(!L:(?A,?L)&!A !arg:?arg)
|
)
& out$(rangeExtract$!arg)
)
& test
$ (0, 1, 2, 4, 6, 7, 8, 11, 12, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 27, 28, 29, 30, 31, 32, 33, 35, 36, 37, 38, 39)</lang>
- Output:
(0,1,2,4,6,7,8,11,12,14,15,16,17,18,19,20,21,22,23,24,25,27,28,29,30,31,32,33,35,36,37,38,39) ==> 0-2,4,6-8,11,12,14-25,27-33,35-39
C
Using the fine tradition of snprintf, rprint is not responsible for allocating output buffer.
It prints the range only if supplied a non-null pointer,
but always returns the output length sans the terminating null,
so caller can allocate buffer.
<lang c>#include <stdio.h>
- include <stdlib.h>
size_t rprint(char *s, int *x, int len) {
- define sep (a > s ? "," : "") /* use comma except before first output */
- define ol (s ? 100 : 0) /* print only if not testing for length */
int i, j; char *a = s; for (i = j = 0; i < len; i = ++j) { for (; j < len - 1 && x[j + 1] == x[j] + 1; j++);
if (i + 1 < j) a += snprintf(s?a:s, ol, "%s%d-%d", sep, x[i], x[j]); else while (i <= j) a += snprintf(s?a:s, ol, "%s%d", sep, x[i++]); } return a - s;
- undef sep
- undef ol
}
int main() { int x[] = { 0, 1, 2, 4, 6, 7, 8, 11, 12, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 27, 28, 29, 30, 31, 32, 33, 35, 36, 37, 38, 39 };
char *s = malloc(rprint(0, x, sizeof(x) / sizeof(int)) + 1); rprint(s, x, sizeof(x) / sizeof(int)); printf("%s\n", s);
return 0; }</lang>
- Output:
0-2,4,6-8,11,12,14-25,27-33,35-39
C++
<lang cpp>
- include <iostream>
- include <iterator>
- include <cstddef>
template<typename InIter>
void extract_ranges(InIter begin, InIter end, std::ostream& os)
{
if (begin == end) return;
int current = *begin++; os << current; int count = 1;
while (begin != end)
{
int next = *begin++;
if (next == current+1)
++count;
else
{
if (count > 2)
os << '-';
else
os << ',';
if (count > 1)
os << current << ',';
os << next;
count = 1;
}
current = next;
}
if (count > 1) os << (count > 2? '-' : ',') << current;
}
template<typename T, std::size_t n>
T* end(T (&array)[n])
{
return array+n;
}
int main() {
int data[] = { 0, 1, 2, 4, 6, 7, 8, 11, 12, 14,
15, 16, 17, 18, 19, 20, 21, 22, 23, 24,
25, 27, 28, 29, 30, 31, 32, 33, 35, 36,
37, 38, 39 };
extract_ranges(data, end(data), std::cout); std::cout << std::endl;
} </lang>
- Output:
0-2,4,6-8,11,12,14-25,27-33,35-39
C#
<lang csharp>using System; using System.Collections.Generic; using System.Linq;
class RangeExtraction {
static void Main()
{
const string testString = "0, 1, 2, 4, 6, 7, 8, 11, 12, 14,15, 16, 17, 18, 19, 20, 21, 22, 23, 24,25, 27, 28, 29, 30, 31, 32, 33, 35, 36,37, 38, 39";
var result = String.Join(",", RangesToStrings(GetRanges(testString)));
Console.Out.WriteLine(result);
}
public static IEnumerable<IEnumerable<int>> GetRanges(string testString)
{
var numbers = testString.Split(new[] { ',' }).Select(x => Convert.ToInt32(x));
var current = new List<int>();
foreach (var n in numbers)
{
if (current.Count == 0)
{
current.Add(n);
}
else
{
if (current.Max() + 1 == n)
{
current.Add(n);
}
else
{
yield return current;
current = new List<int> { n };
}
}
}
yield return current;
}
public static IEnumerable<string> RangesToStrings(IEnumerable<IEnumerable<int>> ranges)
{
foreach (var range in ranges)
{
if (range.Count() == 1)
{
yield return range.Single().ToString();
}
else if (range.Count() == 2)
{
yield return range.Min() + "," + range.Max();
}
else
{
yield return range.Min() + "-" + range.Max();
}
}
}
} </lang>
- Output:
0-2,4,6-8,11,12,14-25,27-33,35-39
C#: Alternate Version
<lang csharp>using System; using System.Collections.Generic; using System.Linq;
namespace RangeExtraction {
internal static class ListExtensions {
internal static string ExtractRange(this IEnumerable<int> values) {
var list = values.Distinct().OrderBy(_ => _).ToArray();
var ranges = new int[0][].AsEnumerable();
var current = 0;
for (var i = 1; ; ++i) {
if (i >= list.Length) {
ranges = ranges.Concat(new[] { new[] { i != current ? current : i - 1, i - 1 } });
break;
}
if (list[i] == list[i - 1] + 1)
continue;
ranges = ranges.Concat(new[] { new[] { current, i - 1 } });
current = i;
}
return string.Join(",", ranges.Select(r => string.Format(r[0] == r[1] ? "{0}" : "{0}-{1}", list[r[0]], list[r[1]])));
}
}
internal class Program {
private static readonly IList<int> VALUES = new[] {
0, 1, 2,
4,
6, 7, 8,
11, 12,
14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25,
27, 28, 29, 30, 31, 32, 33,
35, 36, 37, 38, 39
};
private static void Main(string[] args) {
var rangestr = VALUES.ExtractRange();
Console.WriteLine("values: {{{0}}}", string.Join(", ", VALUES.Select(_=>_.ToString())));
Console.WriteLine("\r\nranges = \"{0}\"", rangestr);
}
}
}</lang>
- Output:
values: {0, 1, 2, 4, 6, 7, 8, 11, 12, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 27, 28, 29, 30, 31, 32, 33, 35, 36, 37, 38, 39}
ranges = "0-2,4,6-8,11-12,14-25,27-33,35-39"
COBOL
<lang cobol> IDENTIFICATION DIVISION.
PROGRAM-ID. extract-range-task.
DATA DIVISION.
WORKING-STORAGE SECTION.
01 data-str PIC X(200) VALUE "0, 1, 2, 4, 6,"
& " 7, 8, 11, 12, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, "
& "24, 25, 27, 28, 29, 30, 31, 32, 33, 35, 36, 37, 38, 39".
01 result PIC X(200).
PROCEDURE DIVISION.
CALL "extract-range" USING CONTENT data-str, REFERENCE result
DISPLAY FUNCTION TRIM(result)
GOBACK
.
END PROGRAM extract-range-task.
IDENTIFICATION DIVISION.
PROGRAM-ID. extract-range.
DATA DIVISION.
LOCAL-STORAGE SECTION.
COPY "nums-table.cpy".
01 difference PIC 999.
01 rng-begin PIC S999.
01 rng-end PIC S999.
01 num-trailing PIC 999.
01 trailing-comma-pos PIC 999.
LINKAGE SECTION.
01 nums-str PIC X(200).
01 extracted-range PIC X(200).
01 extracted-range-len CONSTANT LENGTH extracted-range.
PROCEDURE DIVISION USING nums-str, extracted-range.
CALL "split-nums" USING CONTENT nums-str, ", ",
REFERENCE nums-table
*> Process the table
MOVE nums (1) TO rng-begin
PERFORM VARYING nums-idx FROM 2 BY 1
UNTIL num-nums < nums-idx
SUBTRACT nums (nums-idx - 1) FROM nums (nums-idx)
GIVING difference
*> If number is more than one away from the previous one
*> end the range and start a new one.
IF difference > 1
MOVE nums (nums-idx - 1) TO rng-end
CALL "add-next-range" USING CONTENT rng-begin,
rng-end, REFERENCE extracted-range
MOVE nums (nums-idx) TO rng-begin
END-IF
END-PERFORM
*> Process the last number
MOVE nums (num-nums) TO rng-end
CALL "add-next-range" USING CONTENT rng-begin,
rng-end, REFERENCE extracted-range
*> Remove trailing comma.
CALL "find-num-trailing-spaces"
USING CONTENT extracted-range, REFERENCE num-trailing
COMPUTE trailing-comma-pos =
extracted-range-len - num-trailing
MOVE SPACE TO extracted-range (trailing-comma-pos:1)
GOBACK
.
IDENTIFICATION DIVISION.
PROGRAM-ID. split-nums INITIAL.
DATA DIVISION.
WORKING-STORAGE SECTION.
01 num-len PIC 9.
01 next-num-pos PIC 999.
LINKAGE SECTION.
01 str PIC X(200).
01 delim PIC X ANY LENGTH.
COPY "nums-table.cpy".
PROCEDURE DIVISION USING str, delim, nums-table.
INITIALIZE num-nums
PERFORM UNTIL str = SPACES
INITIALIZE num-len
INSPECT str TALLYING num-len FOR CHARACTERS BEFORE delim
ADD 1 TO num-nums
*> If there are no more instances of delim in the string,
*> add the rest of the string to the last element of the
*> table.
IF num-len = 0
MOVE str TO nums (num-nums)
EXIT PERFORM
ELSE
MOVE str (1:num-len) TO nums (num-nums)
ADD 3 TO num-len GIVING next-num-pos
MOVE str (next-num-pos:) TO str
END-IF
END-PERFORM
.
END PROGRAM split-nums.
IDENTIFICATION DIVISION.
PROGRAM-ID. add-next-range INITIAL.
DATA DIVISION.
WORKING-STORAGE SECTION.
01 num-trailing PIC 999.
01 start-pos PIC 999.
01 range-len PIC 999.
01 begin-edited PIC -ZZ9.
01 end-edited PIC -ZZ9.
LINKAGE SECTION.
01 rng-begin PIC S999.
01 rng-end PIC S999.
01 extracted-range PIC X(200).
01 extracted-range-len CONSTANT LENGTH extracted-range.
PROCEDURE DIVISION USING rng-begin, rng-end, extracted-range.
CALL "find-num-trailing-spaces"
USING CONTENT extracted-range, REFERENCE num-trailing
COMPUTE start-pos = extracted-range-len - num-trailing + 1
SUBTRACT rng-begin FROM rng-end GIVING range-len
MOVE rng-begin TO begin-edited
MOVE rng-end TO end-edited
EVALUATE TRUE
WHEN rng-begin = rng-end
STRING FUNCTION TRIM(begin-edited), ","
INTO extracted-range (start-pos:)
WHEN range-len = 1
STRING FUNCTION TRIM(begin-edited), ",",
FUNCTION TRIM(end-edited), ","
INTO extracted-range (start-pos:)
WHEN OTHER
STRING FUNCTION TRIM(begin-edited), "-",
FUNCTION TRIM(end-edited), ","
INTO extracted-range (start-pos:)
END-EVALUATE
.
END PROGRAM add-next-range.
IDENTIFICATION DIVISION.
PROGRAM-ID. find-num-trailing-spaces.
DATA DIVISION.
LINKAGE SECTION.
01 str PIC X(200).
01 num-trailing PIC 999.
PROCEDURE DIVISION USING str, num-trailing.
INITIALIZE num-trailing
INSPECT str TALLYING num-trailing FOR TRAILING SPACES
.
END PROGRAM find-num-trailing-spaces.
END PROGRAM extract-range.</lang>
nums-table.cpy: <lang cobol> 01 nums-table.
03 num-nums PIC 999.
03 nums-area.
05 nums PIC S999 OCCURS 1 TO 100 TIMES
DEPENDING ON num-nums
INDEXED BY nums-idx.</lang>
- Output:
0-2,4,6-8,11,12,14-25,27-33,35-39
Common Lisp
<lang lisp>(defun format-with-ranges (list)
(unless list (return ""))
(with-output-to-string (s)
(let ((current (first list))
(list (rest list))
(count 1))
(princ current s)
(dolist (next list)
(if (= next (1+ current))
(incf count)
(progn (princ (if (> count 2) "-" ",") s)
(when (> count 1)
(princ current s)
(princ "," s))
(princ next s)
(setf count 1)))
(setf current next))
(when (> count 1)
(princ (if (> count 2) "-" ",") s)
(princ current s)))))
CL-USER> (format-with-ranges (list 0 1 2 4 6 7 8 11 12 14
15 16 17 18 19 20 21 22 23 24
25 27 28 29 30 31 32 33 35 36
37 38 39))
"0-2,4,6-8,11,12,14-25,27-33,35-39" </lang>
D
<lang d>import std.stdio, std.conv, std.string, std.algorithm, std.range;
string rangeExtraction(in int[] items) in {
assert(items.isSorted);
} body {
if (items.empty)
return null;
auto ranges = [[items[0].text]];
foreach (immutable x, immutable y; items.zip(items[1 .. $]))
if (x + 1 == y)
ranges[$ - 1] ~= y.text;
else
ranges ~= [y.text];
return ranges
.map!(r => r.length > 2 ? r[0] ~ "-" ~ r.back : r.join(','))
.join(',');
}
void main() {
foreach (data; [[-8, -7, -6, -3, -2, -1, 0, 1, 3, 4, 5, 7, 8, 9,
10, 11, 14, 15, 17, 18, 19, 20],
[0, 0, 0, 1, 1],
[0, 1, 2, 4, 6, 7, 8, 11, 12, 14, 15, 16, 17, 18,
19, 20, 21, 22, 23, 24, 25, 27, 28, 29, 30, 31,
32, 33, 35, 36, 37, 38, 39]])
data.rangeExtraction.writeln;
}</lang>
- Output:
-8--6,-3-1,3-5,7-11,14,15,17-20 0,0,0,1,1 0-2,4,6-8,11,12,14-25,27-33,35-39
DWScript
<lang delphi>procedure ExtractRanges(const values : array of Integer); begin
var i:=0;
while i<values.Length do begin
if i>0 then
Print(',');
Print(values[i]);
var j:=i+1;
while (j<values.Length) and (values[j]=values[j-1]+1) do
Inc(j);
Dec(j);
if j>i then begin
if j=i+1 then
Print(',')
else Print('-');
Print(values[j]);
end;
i:=j+1;
end;
end;
ExtractRanges([ 0, 1, 2, 4, 6, 7, 8, 11, 12, 14,
15, 16, 17, 18, 19, 20, 21, 22, 23, 24,
25, 27, 28, 29, 30, 31, 32, 33, 35, 36,
37, 38, 39]);</lang>
- Output:
0-2,4,6-8,11,12,14-25,27-33,35-39
E
Cheeky solution: relying on the standard library for finding ranges, and just formatting them ourselves.
<lang e>def rex(numbers :List[int]) {
var region := 0..!0
for n in numbers { region |= n..n }
var ranges := []
for interval in region.getSimpleRegions() {
def a := interval.getOptStart()
def b := interval.getOptBound() - 1
ranges with= if (b > a + 1) {
`$a-$b`
} else if (b <=> a + 1) {
`$a,$b`
} else { # b <=> a
`$a`
}
}
return ",".rjoin(ranges)
}</lang>
<lang e>? rex([ > 0, 1, 2, 4, 6, 7, 8, 11, 12, 14, > 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, > 25, 27, 28, 29, 30, 31, 32, 33, 35, 36, > 37, 38, 39])
- value: "0-2,4,6-8,11,12,14-25,27-33,35-39"
</lang>
EchoLisp
<lang scheme> (define task '(0 1 2 4 6 7 8 11 12 14 15 16 17 18 19 20 21 22 23 24 25 27 28 29 30 31 32 33 35 36 37 38 39))
- 1- GROUPING
(define (group-range item acc) (if
(or (empty? acc) (!= (caar acc) (1- item)))
(cons (cons item item) acc)
(begin (set-car! (car acc) item) acc)))
- intermediate result
- (foldl group-range () task)
- → ((39 . 35) (33 . 27) (25 . 14) (12 . 11) (8 . 6) (4 . 4) (2 . 0))
- 2- FORMATTING
(define (range->string range) (let ((from (rest range)) (to (first range))) (cond ((= from to) (format "%d " from)) ((= to (1+ from)) (format "%d, %d " from to)) (else (format "%d-%d " from to)))))
- 3 - FINAL
(string-join (map range->string (reverse (foldl group-range () task))) ",")
→ "0-2 ,4 ,6-8 ,11, 12 ,14-25 ,27-33 ,35-39 "
</lang>
Eiffel
<lang Eiffel> class RANGE
create make
feature make local extended_range: STRING do extended_range := "0, 1, 2, 4, 6, 7, 8, 11, 12, 14, " + "15, 16, 17, 18, 19, 20, 21, 22, 23, 24, " + "25, 27, 28, 29, 30, 31, 32, 33, 35, 36, " +
"37, 38, 39"
print("Extended range: " + extended_range + "%N") print("Extracted range: " + extracted_range(extended_range) + "%N%N") end
feature extracted_range(sequence: STRING): STRING local elements: LIST[STRING] first, curr: STRING subrange_size, index: INTEGER do sequence.replace_substring_all (", ", ",") elements := sequence.split (',') from index := 2 first := elements.at (1) subrange_size := 0 Result := "" until index > elements.count loop curr := elements.at (index) if curr.to_integer - first.to_integer - subrange_size = 1 then subrange_size := subrange_size + 1 else Result.append(first) if (subrange_size <= 1) then Result.append (", ") else Result.append (" - ") end if (subrange_size >= 1) then Result.append ((first.to_integer + subrange_size).out) Result.append (", ") end
first := curr subrange_size := 0 end index := index + 1 end Result.append(first) if (subrange_size <= 1) then Result.append (", ") else Result.append (" - ") end if (subrange_size >= 1) then Result.append ((first.to_integer + subrange_size).out) end end end </lang>
- Output:
Extended range: 0, 1, 2, 4, 6, 7, 8, 11, 12, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 27, 28, 29, 30, 31, 32, 33, 35, 36, 37, 38, 39 Extracted range: 0 - 2, 4, 6 - 8, 11, 12, 14 - 25, 27 - 33, 35 - 39
Elixir
<lang elixir>defmodule RC do
def range_extract(list) do
max = Enum.max(list) + 2
sorted = Enum.sort([max|list])
canidate_number = hd(sorted)
current_number = hd(sorted)
extract(tl(sorted), canidate_number, current_number, [])
end
defp extract([], _, _, range), do: Enum.reverse(range) |> Enum.join(",")
defp extract([next|rest], canidate, current, range) when current+1 >= next do
extract(rest, canidate, next, range)
end
defp extract([next|rest], canidate, current, range) when canidate == current do
extract(rest, next, next, [to_string(current)|range])
end
defp extract([next|rest], canidate, current, range) do
seperator = if canidate+1 == current, do: ",", else: "-"
str = "#{canidate}#{seperator}#{current}"
extract(rest, next, next, [str|range])
end
end
list = [
0, 1, 2, 4, 6, 7, 8, 11, 12, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 27, 28, 29, 30, 31, 32, 33, 35, 36, 37, 38, 39
] IO.inspect RC.range_extract(list)</lang>
- Output:
"0-2,4,6-8,11,12,14-25,27-33,35-39"
Emacs Lisp
version 1
<lang Emacs Lisp}> (require 'gnus-range) (defun rangext (lst)
(mapconcat (lambda (item)
(if (consp item)
(if (= (+ 1 (car item) ) (cdr item) ) (format "%d,%d" (car item) (cdr item) ) (format "%d-%d" (car item) (cdr item) ))
(format "%d" item)))
(gnus-compress-sequence lst)
","))
(insert (rangext '(0 1 2 4 6 7 8 11 12 14
15 16 17 18 19 20 21 22 23 24
25 27 28 29 30 31 32 33 35 36
37 38 39) ))
</lang>
Output:
0-2,4,6-8,11,12,14-25,27-33,35-39
version 2
<lang Emacs Lisp}> (setq max-lisp-eval-depth 10000)
(defun ab (a ls)
(if ls (if (= (+ a 1) (car ls) )
(abc a (car ls) (cdr ls) ) (format "%d,%s" a (ab (car ls) (cdr ls) )))
(format "%d" a) ))
(defun abc (a b ls)
(if ls (if (= (+ b 1) (car ls) )
(abcd a (car ls) (cdr ls) ) (format "%d,%d,%s" a b (ab (car ls) (cdr ls) )))
(format "%d,%d" a b) ))
(defun abcd (a c ls)
(if ls (if (= (+ c 1) (car ls) )
(abcd a (car ls) (cdr ls) ) (format "%d-%d,%s" a c (ab (car ls) (cdr ls) )))
(format "%d-%d" a c) ))
(defun rangext (ls)
(if ls (ab (car ls) (cdr ls) ) ""))
(insert (rangext '(0 1 2 4 6 7 8 11 12 14
15 16 17 18 19 20 21 22 23 24
25 27 28 29 30 31 32 33 35 36
37 38 39) ))
</lang>
Output:
0-2,4,6-8,11,12,14-25,27-33,35-39
Erlang
<lang Erlang> -module( range ).
-export( [extraction/1, task/0] ).
extraction( [H | T] ) when is_integer(H) ->
Reversed_extracts = extraction_acc( lists:foldl(fun extraction/2, {H, []}, T) ),
string:join( lists:reverse(Reversed_extracts), "," ).
task() ->
io:fwrite( "~p~n", [extraction([0, 1, 2, 4, 6, 7, 8, 11, 12, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 27, 28, 29, 30, 31, 32, 33, 35, 36, 37, 38, 39])] ).
extraction( N, {Start, Acc} ) when N =:= Start + 1 -> {Start, N, Acc}; extraction( N, {Start, Acc} ) -> {N, extraction_acc( {Start, Acc} )}; extraction( N, {Start, Stop, Acc} ) when N =:= Stop + 1 -> {Start, N, Acc}; extraction( N, {Start, Stop, Acc} ) -> {N, extraction_acc( {Start, Stop, Acc} )}.
extraction_acc( {N, Acc} ) -> [erlang:integer_to_list(N) | Acc]; extraction_acc( {Start, Stop, Acc} ) when Stop > Start + 1 -> [erlang:integer_to_list(Start) ++ "-" ++ erlang:integer_to_list(Stop) | Acc]; extraction_acc( {Start, Stop, Acc} ) -> [erlang:integer_to_list(Stop), erlang:integer_to_list(Start) | Acc]. % Reversed </lang>
- Output:
19> range:task(). "0-2,4,6-8,11,12,14-25,27-33,35-39"
Euphoria
<lang euphoria>function extract_ranges(sequence s)
integer first
sequence out
out = ""
if length(s) = 0 then
return out
end if
first = 1
for i = 2 to length(s) do
if s[i] != s[i-1]+1 then
if first = i-1 then
out &= sprintf("%d,", s[first])
elsif first = i-2 then
out &= sprintf("%d,%d,", {s[first],s[i-1]})
else
out &= sprintf("%d-%d,", {s[first],s[i-1]})
end if
first = i
end if
end for
if first = length(s) then
out &= sprintf("%d", s[first])
elsif first = length(s)-1 then
out &= sprintf("%d,%d", {s[first],s[$]})
else
out &= sprintf("%d-%d", {s[first],s[$]})
end if
return out
end function
puts(1, extract_ranges({0, 1, 2, 4, 6, 7, 8, 11, 12, 14, 15, 16, 17, 18, 19,
20, 21, 22, 23, 24, 25, 27, 28, 29, 30, 31, 32, 33, 35, 36, 37, 38, 39}))</lang>
- Output:
0-2,4,6-8,11,12,14-25,27-33,35-39
F#
<lang fsharp>let extractRanges = function
| [] -> Seq.empty
| x::xr ->
let rec loop ys first last = seq {
match ys with
| y::yr when y = last + 1 -> yield! loop yr first y // add to current range
| y::yr -> yield (first, last) // finish current range
yield! loop yr y y // and start next
| [] -> yield (first, last) } // finish final range
loop xr x x
let rangeToString (s,e) =
match e-s with | 0 -> sprintf "%d" s | 1 -> sprintf "%d,%d" s e | _ -> sprintf "%d-%d" s e
let extract = extractRanges >> Seq.map rangeToString >> String.concat ","
printfn "%s" (extract [ 0; 1; 2; 4; 6; 7; 8; 11; 12; 14; 15; 16; 17; 18; 19; 20; 21;
22; 23; 24; 25; 27; 28; 29; 30; 31; 32; 33; 35; 36; 37; 38; 39 ])</lang>
- Output:
0-2,4,6-8,11,12,14-25,27-33,35-39
Forth
<lang forth>create values here
0 , 1 , 2 , 4 , 6 , 7 , 8 , 11 , 12 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 35 , 36 , 37 , 38 , 39 ,
here swap - 1 cells / constant /values
- clip 1- swap cell+ swap ; \ reduce array
- .range2 0 .r ." -" 0 .r ; \ difference two or more
- .range1 0 .r ." , " 0 .r ; \ difference one
- .range0 drop 0 .r ; \ no difference
\ select printing routine
create .range ' .range0 , ' .range1 , ' .range2 ,
does> >r over over - 2 min cells r> + @ execute ;
- .ranges ( a n --)
over @ dup >r >r \ setup first value begin clip dup \ check length array while over @ dup r@ 1+ = \ check if range breaks if r> drop >r else r> r> .range ." , " dup >r >r then repeat 2drop r> r> .range cr \ print last range
values /values .ranges</lang>
- Output:
0-2, 4, 6-8, 11, 12, 14-25, 27-33, 35-39
Go
<lang go>package main
import (
"errors" "fmt" "strconv" "strings"
)
func main() {
rf, err := rangeFormat([]int{
0, 1, 2, 4, 6, 7, 8, 11, 12, 14,
15, 16, 17, 18, 19, 20, 21, 22, 23, 24,
25, 27, 28, 29, 30, 31, 32, 33, 35, 36,
37, 38, 39,
})
if err != nil {
fmt.Println(err)
return
}
fmt.Println("range format:", rf)
}
func rangeFormat(a []int) (string, error) {
if len(a) == 0 {
return "", nil
}
var parts []string
for n1 := 0; ; {
n2 := n1 + 1
for n2 < len(a) && a[n2] == a[n2-1]+1 {
n2++
}
s := strconv.Itoa(a[n1])
if n2 == n1+2 {
s += "," + strconv.Itoa(a[n2-1])
} else if n2 > n1+2 {
s += "-" + strconv.Itoa(a[n2-1])
}
parts = append(parts, s)
if n2 == len(a) {
break
}
if a[n2] == a[n2-1] {
return "", errors.New(fmt.Sprintf(
"sequence repeats value %d", a[n2]))
}
if a[n2] < a[n2-1] {
return "", errors.New(fmt.Sprintf(
"sequence not ordered: %d < %d", a[n2], a[n2-1]))
}
n1 = n2
}
return strings.Join(parts, ","), nil
}</lang>
- Output:
range format: 0-2,4,6-8,11,12,14-25,27-33,35-39
Groovy
Ad Hoc Solution: <lang groovy>def range = { s, e -> s == e ? "${s}," : s == e - 1 ? "${s},${e}," : "${s}-${e}," }
def compressList = { list ->
def sb, start, end
(sb, start, end) = [<<, list[0], list[0]]
for (i in list[1..-1]) {
(sb, start, end) = i == end + 1 ? [sb, start, i] : [sb << range(start, end), i, i]
}
(sb << range(start, end))[0..-2].toString()
}
def compressRanges = { expanded -> compressList(Eval.me('[' + expanded + ']')) }</lang>
Test: <lang groovy>def s =
0, 1, 2, 4, 6, 7, 8, 11, 12, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 27, 28, 29, 30, 31, 32, 33, 35, 36, 37, 38, 39
println (compressRanges(s))</lang>
- Output:
0-2,4,6-8,11,12,14-25,27-33,35-39
Haskell
<lang haskell>import Data.List (intercalate)
extractRange :: [Int] -> String extractRange = intercalate "," . f
where f :: [Int] -> [String]
f (x1 : x2 : x3 : xs) | x1 + 1 == x2 && x2 + 1 == x3
= (show x1 ++ '-' : show xn) : f xs'
where (xn, xs') = g (x3 + 1) xs
g a (n : ns) | a == n = g (a + 1) ns
| otherwise = (a - 1, n : ns)
g a [] = (a - 1, [])
f (x : xs) = show x : f xs
f [] = []</lang>
<lang text>> extractRange $ [0..2] ++ 4 : [6..8] ++ 11 : 12 : [14..25] ++ [27..33] ++ [35..39] "0-2,4,6-8,11,12,14-25,27-33,35-39"</lang>
Icon and Unicon
<lang Icon>procedure main()
R := [ 0, 1, 2, 4, 6, 7, 8, 11, 12, 14,
15, 16, 17, 18, 19, 20, 21, 22, 23, 24,
25, 27, 28, 29, 30, 31, 32, 33, 35, 36,
37, 38, 39 ]
write("Input list := ",list2string(R))
write("Extracted sting := ",s := range_extract(R) | "FAILED")
end
procedure range_extract(R) #: return string/range representation of a list of unique integers local s,sep,low,high,x
every if integer(x:= !R) ~= x then fail # ensure all are integers, R := sort(set(R)) # unique, and sorted
s := sep := ""
while s ||:= sep || ( low := high := get(R) ) do { # lower bound of range
sep := ","
while high := ( R[1] = high + 1 ) do get(R) # find the end of range
if high > low+1 then s ||:= "-" || high # - record range of 3+
else if high = low+1 then push(R,high) # - range of 2, high becomes new low
}
return s
end
procedure list2string(L) #: helper to convert list to string local s
every (s := "[ ") ||:= !L || " " return s || "]"
end</lang>
- Output:
Input list := [ 0 1 2 4 6 7 8 11 12 14 15 16 17 18 19 20 21 22 23 24 25 27 28 29 30 31 32 33 35 36 37 38 39 ] Extracted sting := 0-2,4,6-8,11,12,14-25,27-33,35-39
J
Older versions of J will also need require 'strings'.
<lang j>fmt=: [: ;@(8!:0) [`]`({. ; (',-' {~ 2 < #) ; {:)@.(2 <. #) group=: <@fmt;.1~ 1 ~: 0 , 2 -~/\ ] extractRange=: ',' joinstring group</lang>
Example use:
<lang j> extractRange 0 1 2 4 6 7 8 11 12 14 15 16 17 18 19 20 21 22 23 24 25 27 28 29 30 31 32 33 35 36 37 38 39 0-2,4,6-8,11,12,14-25,27-33,35-39</lang>
and
<lang j> extractRange (-6, 3, 2, 1), 0, 1, 3, 4, 5, 7, 8, 9, 10, 11, 14, 15, 17, 18, 19, 20 -6,-3-1,3-5,7-11,14,15,17-20</lang>
Other examples:
<lang J> extractRange i.101 0-100</lang>
The first 101 non-negative integers
<lang J>
extractRange (-. p:) i.101
0,1,4,6,8-10,12,14-16,18,20-22,24-28,30,32-36,38-40,42,44-46,48-52,54-58,60,62-66,68-70,72,74-78,80-82,84-88,90-96,98-100</lang>
Excluding those which are prime
<lang J>
extractRange 2}. (-. p:) i.101
4,6,8-10,12,14-16,18,20-22,24-28,30,32-36,38-40,42,44-46,48-52,54-58,60,62-66,68-70,72,74-78,80-82,84-88,90-96,98-100</lang>
Also excluding the first two non-negative integers (which are neither prime nor the product of non-empty lists of primes).
Java
<lang java>public class Range{ public static void main(String[] args){ System.out.println(compress2Range("-6, -3, -2, -1, 0, 1, 3, 4, 5, 7," + " 8, 9, 10, 11, 14, 15, 17, 18, 19, 20"));
System.out.println(compress2Range(
"0, 1, 2, 4, 6, 7, 8, 11, 12, 14, " +
"15, 16, 17, 18, 19, 20, 21, 22, 23, 24," +
"25, 27, 28, 29, 30, 31, 32, 33, 35, 36," +
"37, 38, 39"));
}
private static String compress2Range(String expanded){
StringBuilder result = new StringBuilder();
String[] nums = expanded.replace(" ", "").split(",");
int firstNum = Integer.parseInt(nums[0]);
int rangeSize = 0;
for(int i = 1; i < nums.length; i++){
int thisNum = Integer.parseInt(nums[i]);
if(thisNum - firstNum - rangeSize == 1){
rangeSize++;
}else{
if(rangeSize != 0){
result.append(firstNum).append((rangeSize == 1) ? ",": "-")
.append(firstNum+rangeSize).append(",");
rangeSize = 0;
}else{
result.append(firstNum).append(",");
}
firstNum = thisNum;
}
}
if(rangeSize != 0){
result.append(firstNum).append((rangeSize == 1) ? "," : "-").
append(firstNum + rangeSize);
rangeSize = 0;
} else {
result.append(firstNum);
}
return result.toString();
}
}</lang>
- Output:
-6,-3-1,3-5,7-11,14,15,17-20 0-2,4,6-8,11,12,14-25,27-33,35-39
JavaScript
Imperative
<lang javascript>function rangeExtraction(list) {
var len = list.length; var out = []; var i, j;
for (i = 0; i < len; i = j + 1) {
// beginning of range or single
out.push(list[i]);
// find end of range
for (var j = i + 1; j < len && list[j] == list[j-1] + 1; j++);
j--;
if (i == j) {
// single number
out.push(",");
} else if (i + 1 == j) {
// two numbers
out.push(",", list[j], ",");
} else {
// range
out.push("-", list[j], ",");
}
}
out.pop(); // remove trailing comma
return out.join("");
}
// using print function as supplied by Rhino standalone print(rangeExtraction([
0, 1, 2, 4, 6, 7, 8, 11, 12, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 27, 28, 29, 30, 31, 32, 33, 35, 36, 37, 38, 39
]));</lang>
Functional (ES 5)
<lang JavaScript>(function (lstTest) {
'use strict';
function rangeString(xs) {
var iRightmost = xs.length - 1,
lstSeries = xs.reduceRight(function (a, x, i, l) {
return i < iRightmost ? (
// new series if rightward gap > 1
l[i + 1] - x > 1 ? (
x.concat(a)
) : (
// This value prepended to current series if a series
// a series-breaker or the start of the list is at left
(i === 0 | x - l[i - 1]) > 1 ? (
[[x].concat(a[0])].concat(a.slice(1))
// or if the series continues,
// just an unmodified copy of the accumulator
) : a
)
) : x;
}, []);
return lstSeries.map(function (r) {
var lng = r.length,
d = lng > 1 ? r[1] - r[0] : 0;
return d ? r[0] + (d > 1 ? '-' : ',') + r[1] : r[0];
}).join(',');
}
return rangeString(lstTest);
})([0, 1, 2, 4, 6, 7, 8, 11, 12, 14,
15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 27, 28, 29, 30, 31, 32, 33, 35, 36, 37, 38, 39]);</lang>
- Output:
<lang JavaScript>"0-2,4,6-8,11,12,14-25,27-33,35-39"</lang>
jq
<lang kq># Input should be an array def extract:
reduce .[] as $i
# state is an array with integers or [start, end] ranges
([];
if length == 0 then [ $i ]
else ( .[-1]) as $last
| if ($last|type) == "array" then
if ($last[1] + 1) == $i then setpath([-1,1]; $i)
else . + [ $i ]
end
elif ($last + 1) == $i then setpath([-1]; [$last, $i])
else . + [ $i ]
end
end)
| map( if type == "number" then tostring
elif .[0] == .[1] -1
then "\(.[0]),\(.[1])" # satisfy special requirement
else "\(.[0])-\(.[1])" end )
| join(",") ;</lang>
- Command and output:
$ jq -n -f extract_range.jq input.txt "0-2,4,6-8,11,12,14-25,27-33,35-39"
Julia
This is perhaps an idiosyncratic solution. Numbers inside of runs are replaced with Xs, the list is converted into a comma separated string, and then Xs and extra commas are replaced with the range character via a regular expression. <lang Julia> function sprintfrange{T<:Integer}(a::Array{T,1})
len = length(a) 0 < len || return "" dropme = falses(len) dropme[2:end-1] = Bool[a[i-1]==a[i]-1 && a[i+1]==a[i]+1 for i in 2:(len-1)] s = [string(i) for i in a] s[dropme] = "X" s = join(s, ",") replace(s, r",[,X]+,", "-")
end
testa = [ 0, 1, 2, 4, 6, 7, 8, 11, 12, 14,
15, 16, 17, 18, 19, 20, 21, 22, 23, 24,
25, 27, 28, 29, 30, 31, 32, 33, 35, 36,
37, 38, 39]
println("Testing range-style formatting.") println(" ", testa, "\n =>\n ", sprintfrange(testa)) </lang>
- Output:
[0,1,2,4,6,7,8,11,12,14,15,16,17,18,19,20,21,22,23,24,25,27,28,29,30,31,32,33,35,36,37,38,39]
=>
0-2,4,6-8,11,12,14-25,27-33,35-39
K
<lang k>grp : {(&~1=0,-':x)_ x} fmt : {:[1=#s:$x;s;(*s),:[3>#s;",";"-"],*|s]} erng: {{x,",",y}/,//'fmt'grp x}</lang>
- Example:
erng 0 1 2 4 6 7 8 11 12 14 15 16 17 18 19 20 21 22 23 24 25 27 28 29 30 31 32 33 35 36 37 38 39 "0-2,4,6-8,11,12,14-25,27-33,35-39"
Liberty BASIC
<lang lb> s$ = "0, 1, 2, 4, 6, 7, 8, 11, 12, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24," + _
"25, 27, 28, 29, 30, 31, 32, 33, 35, 36, 37, 38, 39"
print ExtractRange$( s$) end
function ExtractRange$( range$)
n = 1
count = ItemCount( range$, ",")
while n <= count
startValue = val( word$( range$, n, ","))
m = n + 1
while m <= count
nextValue = val( word$( range$, m, ","))
if nextValue - startValue <> m - n then exit while
m = m + 1
wend
if m - n > 2 then
ExtractRange$ = ExtractRange$ + str$( startValue) + "-" + str$( startValue + m - n - 1) + ","
else
for i = n to m - 1
ExtractRange$ = ExtractRange$ + str$( startValue + i - n) + ","
next i
end if
n = m
wend
ExtractRange$ = left$( ExtractRange$, len( ExtractRange$) - 1)
end function
function ItemCount( list$, separator$)
while word$( list$, ItemCount + 1, separator$) <> ""
ItemCount = ItemCount + 1
wend
end function </lang>
- Output:
0-2,4,6-8,11,12,14-25,27-33,35-39
LiveCode
Inefficient as it takes 2 passes <lang LiveCode>function rangeExtract nums
local prevNum, znums, rangedNums
set itemDelimiter to ", "
put the first item of nums into prevNum
repeat for each item n in nums
if n is (prevNum + 1) then
put n into prevNum
put "#" & n after znums
else
put n into prevNum
put return & n after znums
end if
end repeat
set itemDelimiter to "#"
repeat for each line z in znums
if z is empty then next repeat
switch the number of items of z
case 1
put z & "," after rangedNums
break
case 2
put item 1 of z & "," & item -1 of z & "," after rangedNums
break
default
put item 1 of z & "-" & item -1 of z & "," after rangedNums
end switch
end repeat
return char 1 to -2 of rangedNums --strip off trailing comma
end rangeExtract </lang> Test <lang LiveCode>command testRangeExtract
local numbers
put "0, 1, 2, 4, 6, 7, 8, 11, 12, 14," \
&& "15, 16, 17, 18, 19, 20, 21, 22, 23, 24," \
&& "25, 27, 28, 29, 30, 31, 32, 33, 35, 36," \
&& "37, 38, 39" into numbers
put rangeExtract(numbers)
end testRangeExtract</lang> Output: <lang LiveCode>0-2,4,6-8,11,12,14-25,27-33,35-39</lang>
Mathematica
<lang Mathematica> rangeExtract[data_List] := ToString[Row[
Riffle[
Flatten[Split[Sort[data], #2 - #1 == 1 &] /. {a_Integer, __, b_} :> Row[{a, "-", b}]],
","]
]];
</lang>
Example:
rangeExtract[{0,1,2,4,6,7,8,11,12,14,15,16,17,18,19,20,21,22,23,24,25,27,28,29,30,31,32,33,35,36,37,38,39}]
"0-2,4,6-8,11,12,14-25,27-33,35-39"
MATLAB / Octave
<lang MATLAB>function S=range_extraction(L)
% Range extraction
L(end+1) = NaN;
S = int2str(L(1));
k = 1;
while (k < length(L)-1)
if (L(k)+1==L(k+1) && L(k)+2==L(k+2) )
m = 2;
while (L(k)+m==L(k+m))
m = m+1;
end
k = k+m-1;
S = [S,'-',int2str(L(k))];
else
k = k+1;
S = [S,',',int2str(L(k))];
end
end
end
disp(range_extraction([0, 1, 2, 4, 6, 7, 8, 11, 12, 14, 15, ...
16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 27, ...
28, 29, 30, 31, 32, 33, 35, 36, 37, 38, 39]))</lang>
- Output (Octave):
0-2,4,6-8,11,12,14-25,27-33,35-39
MUMPS
<lang MUMPS>RANGCONT(X) ;Integer range contraction
NEW Y,I,CONT,NOTFIRST,CURR,PREV,NEXT,SEQ SET Y="",SEQ=0,PREV="",CONT=0 FOR I=1:1:$LENGTH(X,",") DO .SET NOTFIRST=$LENGTH(Y),CURR=$PIECE(X,",",I),NEXT=$PIECE(X,",",I+1) .FOR Q:$EXTRACT(CURR)'=" " S CURR=$EXTRACT(CURR,2,$LENGTH(CURR)) ;clean up leading spaces .S SEQ=((CURR-1)=PREV)&((CURR+1)=NEXT) .IF 'NOTFIRST SET Y=CURR .IF NOTFIRST DO ..;Order matters due to flags ..IF CONT&SEQ ;Do nothing ..IF 'CONT&'SEQ SET Y=Y_","_CURR ..IF CONT&'SEQ SET Y=Y_CURR,CONT=0 ..IF 'CONT&SEQ SET Y=Y_"-",CONT=1 .SET PREV=CURR IF CONT SET Y=Y_PREV K I,CONT,NOTFIRST,CURR,PREV,NEXT,SEQ QUIT Y</lang>
Example:
USER>SET S="0,1,2,4,6,7,8,11,12,14,15,16,17,18,19,20,21,22,23,24,25,27,28,29,30,31,32,33,35,36,37,38,39" USER>W $$RANGCONT^ROSETTA(S) 0-2,4,6-8,11,12,14-25,27-33,35-39
NetRexx
NetRexx Ver. 1
<lang netrexx>/*NetRexx program to test range extraction. ***************************
- 07.08.2012 Walter Pachl derived from my Rexx Version
- Changes: line continuation in aaa assignment changed
- 1e99 -> 999999999
- Do -> Loop
- words(aaa) -> aaa.words()
- word(aaa,i) -> aaa.word(i)
- /
Say 'NetRexx program derived from Rexx' aaa='0 1 2 4 6 7 8 11 12 14 15 16 17 18 19 20 21 22 23 24 25 27 28 29' aaa=aaa' 30 31 32 33 35 36 37 38 39' say 'old='aaa; aaa=aaa 999999999 /* artificial number at the end */ i=0 /* initialize index */ ol= /* initialize output string */ comma= /* will become a ',' lateron */ inrange=0 Loop While i<=aaa.words /* loop for all numbers */
i=i+1 /* index of next number */
n=aaa.word(i) /* the now current number */
If n=999999999 Then Leave /* we are at the end */
If inrange Then Do /* range was opened */
If aaa.word(i+1)<>n+1 Then Do /* following word not in range */
ol=ol||n /* so this number is the end */
inrange=0 /* and the range is over */
End /* else ignore current number */
End
Else Do /* not in a range */
ol=ol||comma||n /* add number (with comma) */
comma=',' /* to the output string */
If aaa.word(i+2)=n+2 Then Do /* if the nr after the next fits */
inrange=1 /* open a range */
ol=ol'-' /* append the range connector */
End
End
End
Say 'new='ol</lang>
- Output:
NetRexx program derived from Rexx old=0 1 2 4 6 7 8 11 12 14 15 16 17 18 19 20 21 22 23 24 25 27 28 29 30 31 32 33 35 36 37 38 39 new=0-2,4,6-8,11,12,14-25,27-33,35-39
NetRexx Ver. 2
<lang NetRexx>/* NetRexx */ options replace format comments java crossref symbols nobinary
runSample(arg) return
-- ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ -- Compact a list of numbers by reducing ranges method compact(expanded) public static
nums = expanded.changestr(',', ' ').space -- remove possible commas & clean up the string
rezult =
RANGE = 0
FIRST = nums.word(1) -- set starting value
loop i_ = 2 to nums.words -- each word in the string is a number to examine
LOCAL = nums.word(i_)
if LOCAL - FIRST - RANGE == 1 then do
-- inside a range
RANGE = RANGE + 1
end
else do
-- not inside a range
if RANGE \= 0 then do
-- we have a range of numbers so collect this and reset
rezult = rezult || FIRST || delim(RANGE) || FIRST + RANGE || ','
RANGE = 0
end
else do
-- just collect this number
rezult = rezult || FIRST || ','
end
FIRST = LOCAL -- bump new starting value
end
end i_
if RANGE \= 0 then do -- terminating value is a range rezult = rezult || FIRST || delim(RANGE) || FIRST + RANGE end else do -- terminating value is a single number rezult = rezult || FIRST end
return rezult.space(1, ',') -- format and return result string
-- ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ -- determine if the range delimiter should be a comma or dash method delim(range) private static
if range == 1 then dlm = ',' else dlm = '-' return dlm
-- ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ -- sample driver method runSample(arg) public static
parse arg userInput td = 0 if userInput.words > 0 then do
-- use input from command line td[0] = td[0] + 1; r_ = td[0]; td[r_] = userInput end
else do
-- use canned test data td[0] = td[0] + 1; r_ = td[0]; td[r_] = ' -6, -3, -2, -1, 0, 1, 3, 4, 5, 7, 8, 9, 10, 11, 14, 15, 17, 18, 19, 20' td[0] = td[0] + 1; r_ = td[0]; td[r_] = ' 0, 1, 2, 4, 6, 7, 8, 11, 12, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 27, 28, 29, 30, 31, 32, 33, 35, 36, 37, 38, 39' td[0] = td[0] + 1; r_ = td[0]; td[r_] = ' -4, -3, -2, 0, 1, 2, 4, 6, 7, 8, 11, 12, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 27, 28, 29, 30, 31, 32, 33, 35, 36, 37, 38, 39' end
loop r_ = 1 to td[0]
say 'Original: ' td[r_].changestr(',', ' ').space(1, ',')
say 'Compacted:' compact(td[r_])
say
end r_
return </lang>
- Output:
Original: -6,-3,-2,-1,0,1,3,4,5,7,8,9,10,11,14,15,17,18,19,20 Compacted: -6,-3-1,3-5,7-11,14,15,17-20 Original: 0,1,2,4,6,7,8,11,12,14,15,16,17,18,19,20,21,22,23,24,25,27,28,29,30,31,32,33,35,36,37,38,39 Compacted: 0-2,4,6-8,11,12,14-25,27-33,35-39 Original: -4,-3,-2,0,1,2,4,6,7,8,11,12,14,15,16,17,18,19,20,21,22,23,24,25,27,28,29,30,31,32,33,35,36,37,38,39 Compacted: -4--2,0-2,4,6-8,11,12,14-25,27-33,35-39
Nim
<lang nim>import parseutils, re, strutils
proc extractRange(input: string): string =
var list = input.replace(re"\s+").split(',').map(parseInt)
var ranges: seq[string] = @[]
var i = 0
while i < list.len:
var first = list[i] # first element in the current range
var offset = i
while True: # skip ahead to the end of the current range
if i + 1 >= list.len:
# reached end of the list
break
if list[i + 1] - (i + 1) != first - offset:
# next element isn't in the current range
break
i.inc
var last = list[i] # last element in the current range
case last - first
of 0: ranges.add($first)
of 1: ranges.add("$1,$2".format([$first, $last]))
else: ranges.add("$1-$2".format([$first, $last]))
i.inc
return ranges.join(",")
echo("""
0, 1, 2, 4, 6, 7, 8, 11, 12, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 27, 28, 29, 30, 31, 32, 33, 35, 36, 37, 38, 39""".extractRange)</lang>
- Output:
0-2, 4, 6-8, 11, 12, 14-25, 27-33, 35-39
Objeck
<lang objeck>class IdentityMatrix {
function : Main(args : String[]) ~ Nil {
Compress2Range("-6, -3, -2, -1, 0, 1, 3, 4, 5, 7, 8, 9, 10, 11, 14, 15, 17, 18, 19, 20")->PrintLine();
Compress2Range("0, 1, 2, 4, 6, 7, 8, 11, 12, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 27, 28, 29, 30, 31, 32, 33, 35, 36, 37, 38, 39")->PrintLine();
}
function : Compress2Range(expanded : String) ~ String {
result := "";
nums := expanded->ReplaceAll(" ", "")->Split(",");
firstNum := nums[0]->ToInt();
rangeSize := 0;
for(i:= 1; i < nums->Size(); i += 1;) {
thisNum := nums[i]->ToInt();
if(thisNum - firstNum - rangeSize = 1) {
rangeSize += 1;
}
else{
if(rangeSize <> 0){
result->Append(firstNum);
result->Append((rangeSize = 1) ? ",": "-");
result->Append(firstNum+rangeSize);
result->Append(",");
rangeSize := 0;
}
else {
result->Append(firstNum);
result->Append(",");
};
firstNum := thisNum;
};
};
if(rangeSize <> 0){
result->Append(firstNum);
result->Append((rangeSize = 1) ? "," : "-");
result->Append(firstNum + rangeSize);
rangeSize := 0;
}
else {
result->Append(firstNum);
};
return result;
}
} </lang>
Oberon-2
Oxford Oberon-2 <lang oberon2> MODULE RangeExtraction; IMPORT Out;
PROCEDURE Range(s: ARRAY OF INTEGER); VAR i,j: INTEGER;
PROCEDURE Emit(sep: CHAR); BEGIN IF i > 2 THEN Out.Int(s[j],3);Out.Char('-');Out.Int(s[j + i - 1],3);Out.Char(sep); INC(j,i) ELSE Out.Int(s[j],3);Out.Char(sep); INC(j) END; END Emit;
BEGIN j := 0;i := -1; LOOP INC(i); IF j + i >= LEN(s) THEN Emit(0AX); EXIT ELSIF s[j + i] # (s[j] + i) THEN Emit(','); i := 0; END END END Range;
VAR seq0: ARRAY 33 OF INTEGER; seq1: ARRAY 20 OF INTEGER; BEGIN seq0[0] := 0; seq0[1] := 1; seq0[2] := 2; seq0[3] := 4; seq0[4] := 6; seq0[5] := 7; seq0[6] := 8; seq0[7] := 11; seq0[8] := 12; seq0[9] := 14; seq0[10] := 15; seq0[11] := 16; seq0[12] := 17; seq0[13] := 18; seq0[14] := 19; seq0[15] := 20; seq0[16] := 21; seq0[17] := 22; seq0[18] := 23; seq0[19] := 24; seq0[20] := 25; seq0[21] := 27; seq0[22] := 28; seq0[23] := 29; seq0[24] := 30; seq0[25] := 31; seq0[26] := 32; seq0[27] := 33; seq0[28] := 35; seq0[29] := 36; seq0[30] := 37; seq0[31] := 38; seq0[32] := 39; Range(seq0); seq1[0] := -6; seq1[1] := -3; seq1[2] := -2; seq1[3] := -1; seq1[4] := 0; seq1[5] := 1; seq1[6] := 3; seq1[7] := 4; seq1[8] := 5; seq1[9] := 7; seq1[10] := 8; seq1[11] := 9; seq1[12] := 10; seq1[13] := 11; seq1[14] := 14; seq1[15] := 15; seq1[16] := 17; seq1[17] := 18; seq1[18] := 19; seq1[19] := 20; Range(seq1) END RangeExtraction. </lang>
- Output:
0- 2, 4, 6- 8, 11, 12, 14- 25, 27- 33, 35- 39 -6, -3- 1, 3- 5, 7- 11, 14, 15, 17- 20
Objective-C
We can use NSIndexSet to do this.
However, it only works for non-negative integers.
<lang objc>#import <Foundation/Foundation.h>
NSString *extractRanges(NSArray *nums) {
NSMutableIndexSet *indexSet = [[NSMutableIndexSet alloc] init];
for (NSNumber *n in nums) {
if ([n integerValue] < 0)
@throw [NSException exceptionWithName:NSInvalidArgumentException reason:@"negative number not supported" userInfo:nil];
[indexSet addIndex:[n unsignedIntegerValue]];
}
NSMutableString *s = [[NSMutableString alloc] init];
[indexSet enumerateRangesUsingBlock:^(NSRange range, BOOL *stop) {
if (s.length)
[s appendString:@","];
if (range.length == 1)
[s appendFormat:@"%lu", range.location];
else if (range.length == 2)
[s appendFormat:@"%lu,%lu", range.location, range.location+1];
else
[s appendFormat:@"%lu-%lu", range.location, range.location+range.length-1];
}];
return s;
}
int main() {
@autoreleasepool {
NSLog(@"%@", extractRanges(@[@0, @1, @2, @4, @6, @7, @8, @11, @12, @14,
@15, @16, @17, @18, @19, @20, @21, @22, @23, @24,
@25, @27, @28, @29, @30, @31, @32, @33, @35, @36,
@37, @38, @39]));
} return 0;
}</lang>
- Output:
0-2,4,6-8,11,12,14-25,27-33,35-39
OCaml
<lang ocaml>let range_extract = function
| [] -> []
| x::xs ->
let f (i,j,ret) k =
if k = succ j then (i,k,ret) else (k,k,(i,j)::ret) in
let (m,n,ret) = List.fold_left f (x,x,[]) xs in
List.rev ((m,n)::ret)
let string_of_range rng =
let str (a,b) = if a = b then string_of_int a else Printf.sprintf "%d%c%d" a (if b = succ a then ',' else '-') b in String.concat "," (List.map str rng)
let () =
let li =
[ 0; 1; 2; 4; 6; 7; 8; 11; 12; 14; 15; 16; 17; 18; 19; 20; 21;
22; 23; 24; 25; 27; 28; 29; 30; 31; 32; 33; 35; 36; 37; 38; 39 ]
in
let rng = range_extract li in
print_endline(string_of_range rng)</lang>
- Output:
0-2,4,6-8,11,12,14-25,27-33,35-39
ooRexx
<lang ooRexx>/* Rexx */
parse arg userInput call runSample userInput return exit
-- ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ -- Compact a list of numbers by reducing ranges compact: procedure --trace ?r;nop
parse arg expanded
nums = expanded~changestr(',', ' ')~space -- remove possible commas & clean up the string
rezult =
RANGE = 0
FIRST = nums~word(1) -- set starting value
loop i_ = 2 to nums~words -- each word in the string is a number to examine
LOCAL = nums~word(i_)
if LOCAL - FIRST - RANGE == 1 then do
-- inside a range
RANGE += 1
end
else do
-- not inside a range
if RANGE \= 0 then do
-- we have a range of numbers so collect this and reset
rezult = rezult || FIRST || delim(RANGE) || FIRST + RANGE || ','
RANGE = 0
end
else do
-- just collect this number
rezult = rezult || FIRST || ','
end
FIRST = LOCAL -- bump new starting value
end
end i_
if RANGE \= 0 then do
-- collect terminating value (a range)
rezult = rezult || FIRST || delim(RANGE) || FIRST + RANGE
end
else do
-- collect terminating value (a single number)
rezult = rezult || FIRST
end
return rezult~space(1, ',') -- format and return result string
-- ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ -- determine if the range delimiter should be a comma or dash delim: procedure
parse arg range . if range == 1 then dlm = ',' else dlm = '-' return dlm
-- ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ -- sample driver runSample: procedure parse arg userInput td. = 0 if userInput~words > 0 then do
td.0 += 1; r_ = td.0; td.r_ = userInput end
else do
td.0 += 1; r_ = td.0; td.r_ = '-6 -3 -2 -1 0 1 3 4 5 7 8 9 10 11 14 15 17 18 19 20' td.0 += 1; r_ = td.0; td.r_ = '0, 1, 2, 4, 6, 7, 8, 11, 12, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 27, 28, 29, 30, 31, 32, 33, 35, 36, 37, 38, 39' td.0 += 1; r_ = td.0; td.r_ = '-4, -3, -2, 0, 1, 2, 4, 6, 7, 8, 11, 12, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 27, 28, 29, 30, 31, 32, 33, 35, 36, 37, 38, 39' end
loop r_ = 1 to td.0
say 'Original: ' td.r_~changestr(',', ' ')~space(1, ',')
say 'Compacted:' compact(td.r_)
say
end r_
return </lang>
- Output:
Original: -6,-3,-2,-1,0,1,3,4,5,7,8,9,10,11,14,15,17,18,19,20 Compacted: -6,-3-1,3-5,7-11,14,15,17-20 Original: 0,1,2,4,6,7,8,11,12,14,15,16,17,18,19,20,21,22,23,24,25,27,28,29,30,31,32,33,35,36,37,38,39 Compacted: 0-2,4,6-8,11,12,14-25,27-33,35-39 Original: -4,-3,-2,0,1,2,4,6,7,8,11,12,14,15,16,17,18,19,20,21,22,23,24,25,27,28,29,30,31,32,33,35,36,37,38,39 Compacted: -4--2,0-2,4,6-8,11,12,14-25,27-33,35-39
OxygenBasic
<lang oxygenbasic>
dim sys ints(100) ints=> 0, 1, 2, 4, 6, 7, 8, 11, 12, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 27, 28, 29, 30, 31, 32, 33, 35, 36, 37, 38, 39
function ShowRange(sys*i) as string
'==================================
pr=""
n=0
e=0
j=0
k=-1
do
j++
n=i(j)
e=i(j+1)
if e<j then
exit do
end if
if e=n+1 and i(j+2)=n+2 then 'LOOKAHEAD
if k=-1 then k=n
else
if k>=0 then
pr+=k "-" i(j+1) ", " 'RANGE OF VALUES
j++
k=-1
else
pr+=n ", " 'SINGLE VALUES
end if
end if
end do
return left pr, len(pr)-2
end function
print ShowRange ints
</lang>
Oz
<lang oz>declare
fun {Extract Xs}
{CommaSeparated
{Map {ExtractRanges Xs} RangeToString}}
end
fun {ExtractRanges Xs}
fun {Loop Ys Start End}
case Ys
of Y|Yr andthen Y == End+1 then {Loop Yr Start Y}
[] Y|Yr then Start#End|{Loop Yr Y Y}
[] nil then [Start#End]
end
end
in
case Xs
of X|Xr then {Loop Xr X X}
[] nil then nil
end
end
fun {RangeToString S#E}
if E-S >= 2 then
{VirtualString.toString S#"-"#E}
else
{CommaSeparated
{Map {List.number S E 1} Int.toString}}
end
end
fun {CommaSeparated Xs}
{Flatten {Intersperse "," Xs}}
end
fun {Intersperse Sep Xs}
case Xs of X|Y|Xr then
X|Sep|{Intersperse Sep Y|Xr}
else
Xs
end
end
in
{System.showInfo
{Extract [ 0 1 2 4 6 7 8 11 12 14
15 16 17 18 19 20 21 22 23 24
25 27 28 29 30 31 32 33 35 36
37 38 39 ]}}</lang>
- Output:
0-2,4,6-8,11,12,14-25,27-33,35-39
Pascal
<lang Pascal>program RangeExtraction;
{$mode objfpc}{$H+}
uses
{$IFDEF UNIX}{$IFDEF UseCThreads}
cthreads,
{$ENDIF}{$ENDIF}
SysUtils;
function RangeExtraction(const Seq: array of integer): String; const
SubSeqLen = 3; // minimal length of the range, can be changed.
var
i, j: Integer; Separator: string = ;
begin
Result := ;
i := Low(Seq);
while i <= High(Seq) do
begin
j := i;
// All subsequent values, starting from i, up to High(Seq) possibly
while ((j < High(Seq)) and ((Seq[j+1]-Seq[j]) = 1)) do
Inc(j);
// is it a range ?
if ((j-i) >= (SubSeqLen-1)) then
begin
Result := Result + Format(Separator+'%d-%d',[Seq[i],Seq[j]]);
i := j+1; // Next value to be processed
Separator := ',';
end
else
begin
// Loop, to process the case SubSeqLen > 3
while i<=j do
begin
Result := Result + Format(Separator+'%d',[Seq[i]]);
Inc(i); // Next value to be processed
Separator := ',';
end;
end;
end;
End;
procedure DisplayRange(const Seq: array of integer); var
i: Integer;
begin
Write(Format('[%d', [Seq[Low(Seq)]]));
for i := Low(Seq) + 1 to High(Seq) do
Write(Format(',%d', [Seq[i]]));
WriteLn('] => ' + RangeExtraction(Seq));
WriteLn;
End;
begin
DisplayRange([0]); DisplayRange([0,1]); DisplayRange([0,2]); DisplayRange([0,1,2]); DisplayRange([0,1,2,3]); DisplayRange([0,1,2,3,4,5,6,7]); DisplayRange([0,2,3,4,5,6,7,9]); DisplayRange([0,2,4,6,8,10]); DisplayRange([0,1,2,3,4,5,6,7,9]); DisplayRange([0,1,2,3,4,6,9,10,11,12]);
DisplayRange([
0, 1, 2, 4, 6, 7, 8, 11, 12, 14,
15, 16, 17, 18, 19, 20, 21, 22, 23, 24,
25, 27, 28, 29, 30, 31, 32, 33, 35, 36,
37, 38, 39]);
ReadLn;
end. </lang>
- Output:
[0] => 0 [0,1] => 0,1 [0,2] => 0,2 [0,1,2] => 0-2 [0,1,2,3] => 0-3 [0,1,2,3,4,5,6,7] => 0-7 [0,2,3,4,5,6,7,9] => 0,2-7,9 [0,2,4,6,8,10] => 0,2,4,6,8,10 [0,1,2,3,4,5,6,7,9] => 0-7,9 [0,1,2,3,4,6,9,10,11,12] => 0-4,6,9-12 [0,1,2,4,6,7,8,11,12,14,15,16,17,18,19,20,21,22,23,24,25,27,28,29,30,31,32,33,35 ,36,37,38,39] => 0-2,4,6-8,11,12,14-25,27-33,35-39
Perl
Using regexes. Also handles +/- and negative integer ranges.
<lang Perl>sub rangext {
my $str = join ' ', @_;
1 while $str =~ s{([+-]?\d+) ([+-]?\d+)}
{$1.(abs($2 - $1) == 1 ? '~' : ',').$2}eg; # abs for neg ranges
$str =~ s/(\d+)~(?:[+-]?\d+~)+([+-]?\d+)/$1-$2/g;
$str =~ tr/~/,/;
return $str;
}
- Test and display
my @test = qw(0 1 2 4 6 7 8 11 12 14,
15 16 17 18 19 20 21 22 23 24,
25 27 28 29 30 31 32 33 35 36,
37 38 39);
print rangext(@test), "\n";</lang>
- Output:
0-2,4,6-8,11,12,14-25,27-33,35-39
<lang Perl>use Set::IntSpan; sub rangext { return Set::IntSpan->new(@_) . } # stringized</lang>
<lang Perl>use Set::IntSpan::Fast; sub rangext { return Set::IntSpan::Fast->new(@_)->as_string }</lang>
Set::IntSpan and Set::IntSpan::Fast are similar. "Fast" does a binary search for member testing (not part of the task here). Both accept negatives.
Perl 6
<lang Perl6>sub range-extraction (*@ints) {
my $prev = NaN; my @ranges;
for @ints -> $int {
if $int == $prev + 1 {
@ranges[*-1].push: $int;
}
else {
@ranges.push: [$int];
}
$prev = $int;
}
join ',', @ranges.map: -> @r { @r > 2 ?? "@r[0]-@r[*-1]" !! @r }
}
say range-extraction
-6, -3, -2, -1, 0, 1, 3, 4, 5, 7, 8, 9, 10, 11, 14, 15, 17, 18, 19, 20;
say range-extraction
0, 1, 2, 4, 6, 7, 8, 11, 12, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 27, 28, 29, 30, 31, 32, 33, 35, 36, 37, 38, 39;</lang>
- Output:
-6,-3-1,3-5,7-11,14,15,17-20 0-2,4,6-8,11,12,14-25,27-33,35-39
Phix
<lang Phix>function spout(integer first, integer this, sequence s) string res
if first=this-1 then
res = sprintf("%d",s[first])
else
res = sprintf("%d%s%d",{s[first],iff(first=this-2?',':'-'),s[this-1]})
end if
return res
end function
function extract_ranges(sequence s) integer first = 1 string out = ""
if length(s)!=0 then
for i=2 to length(s) do
if s[i]!=s[i-1]+1 then
out &= spout(first,i,s)&','
first = i
end if
end for
out &= spout(first,length(s)+1,s)
end if
return out
end function
puts(1,extract_ranges({0,1,2,4,6,7,8,11,12,14,15,16,17,18,19,20,21,22,23,24,25,27,28,29,30,31,32,33,35,36,37,38,39}))</lang>
- Output:
0-2,4,6-8,11,12,14-25,27-33,35-39
PicoLisp
<lang PicoLisp>(de rangeextract (Lst)
(glue ","
(make
(while Lst
(let (N (pop 'Lst) M N)
(while (= (inc M) (car Lst))
(setq M (pop 'Lst)) )
(cond
((= N M) (link N))
((= (inc N) M) (link N M))
(T (link (list N '- M))) ) ) ) ) ) )</lang>
- Output:
: (rangeextract
(0 1 2 4 6 7 8 11 12 14 15 16 17 18 19 20 21 22
23 24 25 27 28 29 30 31 32 33 35 36 37 38 39 ) )
-> "0-2,4,6-8,11,12,14-25,27-33,35-39"
PL/I
<lang pli>/* Modified 19 November 2011 to meet requirement that there be at */ /* least 3 items in a run. */ range_extraction: /* 17 August 2010 */
procedure options (main); declare (c, d) character (1); declare (old, new, initial) fixed binary (31); declare in file; declare out file output;
open file (in) title ('/range2.dat,type(text),recsize(80)' );
open file (out) output title ('/range2.out,type(text),recsize(70)');
c = ' '; d = ',';
get file (in) list (old);
do forever;
initial = old;
on endfile (in) begin;
put file (out) edit (c, trim(old)) (a);
stop;
end;
get file (in) list (new);
if new = old+1 then
do; /* we have a run. */
on endfile (in) begin;
if old > initial+1 then d = '-';
put file (out) edit (c, trim(initial), d, trim(old) ) (a);
stop;
end;
do while (new = old+1);
old = new;
get file (in) list (new);
end;
/* At this point, old holds the last in a run; */
/* initial holds the first in a run. */
/* if there are only two members in a run, don't use the */
/* range notation. */
if old > initial+1 then d = '-';
put file (out) edit (c, trim(initial), d, trim(old) ) (a);
old = new;
end;
else /* we have an isolated value. */
do;
put file (out) edit (c, trim(old)) (a);
old = new;
end;
c, d = ',';
end;
end range_extraction;</lang>
OUTPUT 17/8/2010: <lang>
0-2,4,6-8,11-12,14-25,27-33,35-39
</lang>
- Output:
0-2,4,6-8,11,12,14-25,27-33,35-39
PowerShell
<lang PowerShell> function range-extraction($arr) {
if($arr.Count -gt 2) {
$a, $b, $c, $arr = $arr
$d = $e = $c
if((($a + 1) -eq $b) -and (($b + 1) -eq $c)) {
$test = $true
while($arr -and $test) {
$d = $e
$e, $arr = $arr
$test = ($d+1) -eq $e
}
if($test){"$a-$e"}
elseif((-not $arr) -and $test){"$a-$d"}
elseif(-not $arr){"$a-$d,$e"}
else{"$a-$d," + (range-extraction (@($e)+$arr))}
}
elseif(($b + 1) -eq $c) {"$a," + (range-extraction (@($b, $c)+$arr))}
else {"$a,$b," + (range-extraction (@($c)+$arr))}
} else {
switch($arr.Count) {
0 {""}
1 {"$arr"}
2 {"$($arr[0]),$($arr[1])"}
}
}
} range-extraction @(0, 1, 2, 4, 6, 7, 8, 11, 12, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 27, 28, 29, 30, 31, 32, 33, 35, 36, 37, 38, 39) </lang> Output:
0-2,4,6-8,11,12,14-25,27-33,35-39
Prolog
Works with SWI-Prolog and library clpfd.
The code uses three predicates extract_Range/2, study_Range/2 and pack_Range/2.
Every predicate works in both directions arg1 towards arg2 and arg2 towards arg1, so that Range extraction and Range expansion work with the same predicates but in reverse order.
<lang Prolog>range_extract :-
L = [0, 1, 2, 4, 6, 7, 8, 11, 12, 14,
15, 16, 17, 18, 19, 20, 21, 22, 23, 24,
25, 27, 28, 29, 30, 31, 32, 33, 35, 36,
37, 38, 39] ,
writeln(L),
pack_Range(L, LP),
maplist(study_Range, R, LP),
extract_Range(LA, R),
atom_chars(A, LA),
writeln(A).
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% extract_Range(?In, ?Out)
% In : '-6,-3--1,3-5,7-11,14,15,17-20' =>
% Out : [-6], [-3--1], [3-5],[7-11], [14],[15], [17-20]
%
extract_Range([], []).
extract_Range(X , [Range | Y1]) :-
get_Range(X, U-U, Range, X1),
extract_Range(X1, Y1).
get_Range([], Range-[], Range, []). get_Range([','|B], Range-[], Range, B) :- !.
get_Range([A | B], EC, Range, R) :- append_dl(EC, [A | U]-U, NEC), get_Range(B, NEC, Range, R).
append_dl(X-Y, Y-Z, X-Z).
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % % study Range(?In, ?Out) % In : [-6] % Out : [-6,-6] % % In : [-3--1] % Out : [-3, -1] % study_Range(Range1, [Deb, Deb]) :-
catch(number_chars(Deb, Range1), Deb, false).
study_Range(Range1, [Deb, Fin]) :-
append(A, ['-'|B], Range1),
A \= [],
number_chars(Deb, A),
number_chars(Fin, B).
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %
- - use_module(library(clpfd)).
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % % Pack Range(?In, ?Out) % In : -6, % Out : [-6] % % In : -3, -2,-1 % Out : [-3,-1] % pack_Range([],[]).
pack_Range([X|Rest],[[X | V]|Packed]):-
run(X,Rest, [X|V], RRest), pack_Range(RRest,Packed).
run(Fin,[Other|RRest], [Deb, Fin],[Other|RRest]):- Fin #\= Deb, Fin #\= Deb + 1, Other #\= Fin+1.
run(Fin,[],[_Var, Fin],[]).
run(Var,[Var1|LRest],[Deb, Fin], RRest):- Fin #\= Deb, Fin #\= Deb + 1, Var1 #= Var + 1, run(Var1,LRest,[Deb, Fin], RRest).
run(Val,[Other|RRest], [Val, Val],[Other|RRest]). </lang>
- Output:
?- range_extract. [0,1,2,4,6,7,8,11,12,14,15,16,17,18,19,20,21,22,23,24,25,27,28,29,30,31,32,33,35,36,37,38,39] 0-2,4,6-8,11,12,14-25,27-33,35-39 true
PureBasic
Even though the example integer list only includes ascending ranges this code will also handles descending ranges. <lang PureBasic>DataSection
Data.i 33 ;count of elements to be read Data.i 0, 1, 2, 4, 6, 7, 8, 11, 12, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24 Data.i 25, 27, 28, 29, 30, 31, 32, 33, 35, 36, 37, 38, 39
EndDataSection
NewList values()
- setup list
Define elementCount, i Read.i elementCount For i = 1 To elementCount
AddElement(values()): Read.i values()
Next
Procedure.s rangeExtract(List values())
Protected listSize = ListSize(values()) - 1
Protected rangeMarker, rangeStart, rangeIncrement, retraceSteps, rangeSize, endOfRange, output.s, sub.s
ForEach values()
rangeStart = values():
sub = Str(rangeStart)
If NextElement(values())
retraceSteps = 1
rangeIncrement = values() - rangeStart
If rangeIncrement = 1 Or rangeIncrement = -1
;found start of possible range
If ListIndex(values()) <> listSize
retraceSteps = 2
rangeSize = 2
endOfRange = #False
rangeMarker = values()
While NextElement(values())
If values() - rangeMarker <> rangeIncrement
endOfRange = #True
Break
EndIf
rangeSize + 1
rangeMarker = values()
Wend
If rangeSize > 2
sub = Str(rangeStart) + "-" + Str(rangeMarker)
If Not endOfRange
retraceSteps = 0 ;at end of list
Else
retraceSteps = 1
EndIf
EndIf
EndIf
EndIf
;return to the value before look-aheads
While retraceSteps > 0
PreviousElement(values()): retraceSteps - 1
Wend
EndIf
output + sub + ","
Next
ProcedureReturn RTrim(output, ",")
EndProcedure
If OpenConsole()
PrintN(rangeExtract(values())) Print(#CRLF$ + #CRLF$ + "Press ENTER to exit") Input() CloseConsole()
EndIf</lang>
- Output:
0-2,4,6-8,11,12,14-25,27-33,35-39
Python
<lang python>def range_extract(lst):
'Yield 2-tuple ranges or 1-tuple single elements from list of increasing ints'
lenlst = len(lst)
i = 0
while i< lenlst:
low = lst[i]
while i <lenlst-1 and lst[i]+1 == lst[i+1]: i +=1
hi = lst[i]
if hi - low >= 2:
yield (low, hi)
elif hi - low == 1:
yield (low,)
yield (hi,)
else:
yield (low,)
i += 1
def printr(ranges):
print( ','.join( (('%i-%i' % r) if len(r) == 2 else '%i' % r)
for r in ranges ) )
if __name__ == '__main__':
for lst in [[-8, -7, -6, -3, -2, -1, 0, 1, 3, 4, 5, 7,
8, 9, 10, 11, 14, 15, 17, 18, 19, 20],
[0, 1, 2, 4, 6, 7, 8, 11, 12, 14, 15, 16, 17, 18, 19, 20, 21, 22,
23, 24, 25, 27, 28, 29, 30, 31, 32, 33, 35, 36, 37, 38, 39]]:
#print(list(range_extract(lst)))
printr(range_extract(lst))</lang>
- Output:
-8--6,-3-1,3-5,7-11,14,15,17-20 0-2,4,6-8,11,12,14-25,27-33,35-39
- Output:
if the printr(...) statement is commented-out instead of the print(...) statement directly above it.
This shows the tuples yielded by generator function range_extract.
[(-8, -6), (-3, 1), (3, 5), (7, 11), (14,), (15,), (17, 20)] [(0, 2), (4,), (6, 8), (11,), (12,), (14, 25), (27, 33), (35, 39)]
Qi
<lang qi> (define make-range
Start Start -> ["," Start] Start End -> ["," Start "," End] where (= End (+ Start 1)) Start End -> ["," Start "-" End])
(define range-extract-0
Start End [] -> (make-range Start End) Start End [A|As] -> (range-extract-0 Start A As) where (= (+ 1 End) A) Start End [A|As] -> (append (make-range Start End) (range-extract-0 A A As)))
(define range-extract
[A |As] -> (FORMAT NIL "~{~a~}" (tail (range-extract-0 A A As))))
(range-extract [ 0 1 2 4 6 7 8 11 12 14
15 16 17 18 19 20 21 22 23 24
25 27 28 29 30 31 32 33 35 36
37 38 39])
</lang>
- Output:
0-2,4,6-8,11,12,14-25,27-33,35-39
R
<lang rsplus>extract.range = function(v)
{r = c(1, which(diff(v) != 1) + 1, length(v) + 1)
# 'r' holds the index of the start of each run of sequential
# elements.
paste0(collapse = ",", v[head(r, -1)], ifelse(diff(r) == 1, "",
paste0(
ifelse(diff(r) == 2, ",", "-"),
v[r[-1] - 1])))}
print(extract.range(c(
-6, -3, -2, -1, 0, 1, 3, 4, 5, 7, 8, 9, 10, 11, 14, 15, 17, 18, 19, 20)))
print(extract.range(c(
0, 1, 2, 4, 6, 7, 8, 11, 12, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 27, 28, 29, 30, 31, 32, 33, 35, 36, 37, 38, 39)))</lang>
Racket
<lang Racket>
- lang racket
(define (list->ranges xs)
(define (R lo hi)
(if (= lo hi) (~a lo) (~a lo (if (= 1 (- hi lo)) "," "-") hi)))
(let loop ([xs xs] [lo #f] [hi #f] [r '()])
(cond [(null? xs) (string-join (reverse (if lo (cons (R lo hi) r) r)) ",")]
[(not hi) (loop (cdr xs) (car xs) (car xs) r)]
[(= 1 (- (car xs) hi)) (loop (cdr xs) lo (car xs) r)]
[else (loop xs #f #f (cons (R lo hi) r))])))
(list->ranges '(0 1 2 4 6 7 8 11 12 14 15 16 17 18 19 20 21 22 23
24 25 27 28 29 30 31 32 33 35 36 37 38 39))
- -> "0-2,4,6-8,11,12,14-25,27-33,35-39"
</lang>
REXX
Note that the two numbers 11 and 12 are not considered a range.
version 1
This REXX version isn't limited to integers. <lang rexx>/*REXX program creates a range extraction from a list of numbers (can be neg.)*/ old=0 1 2 4 6 7 8 11 12 14 15 16 17 18 19 20 21 22 23 24 25 27 28 29 30 31 32 33 35 36 37 38 39
- =words(old) /*number of integers in the number list*/
new= /*the new list, possibly with ranges. */
do j=1 to #; x=word(old,j) /*obtain Jth number in the old list. */
new=new',' x /*append " " to " new " */
inc=1 /*start with an increment of one (1). */
do k=j+1 to #; y=word(old,k) /*get the Kth number in the number list*/
if y\=x+inc then leave /*is this number not > previous by inc?*/
inc=inc+1; g=y /*increase the range, assign G (good).*/
end /*k*/
if k-1=j | g=x+1 then iterate /*Is the range=0│1? Then keep truckin'*/
new=new'-'g; j=k-1 /*indicate a range of #s; change index*/
end /*j*/
new=space(substr(new, 2), 0) /*elide leading comma, also all blanks.*/ say 'old:' old /*display the old range of numbers. */ say 'new:' new /* " " new list " " */
/*stick a fork in it, we're all done. */</lang>
- Output:
old: 0 1 2 4 6 7 8 11 12 14 15 16 17 18 19 20 21 22 23 24 25 27 28 29 30 31 32 33 35 36 37 38 39 new: 0-2,4,6-8,11,12,14-25,27-33,35-39
version 1a
The REXX version is the same as above, but doesn't modify a do loop's index (j). <lang rexx>/*REXX program creates a range extraction from a list of numbers (can be neg.)*/ old=0 1 2 4 6 7 8 11 12 14 15 16 17 18 19 20 21 22 23 24 25 27 28 29 30 31 32 33 35 36 37 38 39
- =words(old); j=0 /*number of integers in the number list*/
new= /*the new list, possibly with ranges. */
do while j<#; j=j+1; x=word(old,j) /*get the Jth number in the number list*/
new=new',' x /*append " " to " new " */
inc=1 /*start with an increment of one (1). */
do k=j+1 to #; y=word(old,k) /*get the Kth number in the number list*/
if y\=x+inc then leave /*is this number not > previous by inc?*/
inc=inc+1; g=y /*increase the range, assign G (good).*/
end /*k*/
if k-1=j | g=x+1 then iterate /*Is the range=0│1? Then keep truckin'*/
new=new'-'g; j=k-1 /*indicate a range of numbers; change J*/
end /*while*/
new=space(substr(new, 2), 0) /*elide leading comma, also all blanks.*/ say 'old:' old /*display the old range of numbers. */ say 'new:' new /* " " new list " " */
/*stick a fork in it, we're all done. */</lang>
output is the same as the 1st REXX version.
version 2
Somewhat simplified !?! <lang rexx>/*REXX program to test range extraction. ******************************
- 07.08.2012 Walter Pachl
- /
aaa='0 1 2 4 6 7 8 11 12 14 15 16 17 18 19 20 21 22 23 24 25 27 28 29',
'30 31 32 33 35 36 37 38 39'
say 'old='aaa; aaa=aaa 1e99 /* artificial number at the end */ i=0 /* initialize index */ ol= /* initialize output string */ comma= /* will become a ',' lateron */ inrange=0 Do While i<=words(aaa) /* loop for all numbers */
i=i+1 /* index of next number */
n=word(aaa,i) /* the now current number */
If n=1e99 Then Leave /* we are at the end */
If inrange Then Do /* range was opened */
If word(aaa,i+1)<>n+1 Then Do /* following word not in range */
ol=ol||n /* so this number is the end */
inrange=0 /* and the range is over */
End /* else ignore current number */
End
Else Do /* not in a range */
ol=ol||comma||n /* add number (with comma) */
comma=',' /* to the output string */
If word(aaa,i+2)=n+2 Then Do /* if the nr after the next fits */
inrange=1 /* open a range */
ol=ol'-' /* append the range connector */
End
End
End
Say 'new='ol </lang> Output is the same as above.
Ruby
<lang ruby>def range_extract(l)
# pad the list with a big value, so that the last loop iteration will # append something to the range sorted, range = l.sort.concat([Float::MAX]), [] canidate_number = sorted.first
# enumerate over the sorted list in pairs of current number and next by index
sorted.each_cons(2) do |current_number, next_number|
# if there is a gap between the current element and its next by index
if current_number.succ < next_number
# if current element is our first or our next by index
if canidate_number == current_number
# put the first element or next by index into our range as a string
range << canidate_number.to_s
else
# if current element is not the same as the first or next
# add [first or next, first or next equals current add , else -, current]
seperator = canidate_number.succ == current_number ? "," : "-"
range << "%d%s%d" % [canidate_number, seperator, current_number]
end
# make the first element the next element
canidate_number = next_number
end
end
range.join(',')
end
lst = [
0, 1, 2, 4, 6, 7, 8, 11, 12, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 27, 28, 29, 30, 31, 32, 33, 35, 36, 37, 38, 39
]
p rng = range_extract(lst)</lang>
- Output:
"0-2,4,6-8,11,12,14-25,27-33,35-39"
Scala
<lang scala>object Range {
def spanRange(ls:List[Int])={
var last=ls.head
ls span {x => val b=x<=last+1; last=x; b}
}
def toRangeList(ls:List[Int]):List[List[Int]]=ls match {
case Nil => List()
case _ => spanRange(ls) match {
case (range, Nil) => List(range)
case (range, rest) => range :: toRangeList(rest)
}
}
def toRangeString(ls:List[List[Int]])=ls map {r=>
if(r.size<3) r mkString ","
else r.head + "-" + r.last
} mkString ","
def main(args: Array[String]): Unit = {
var l=List(0, 1, 2, 4, 6, 7, 8, 11, 12, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25,
27, 28, 29, 30, 31, 32, 33, 35, 36, 37, 38, 39)
println(toRangeString(toRangeList(l)))
}
}</lang>
- Output:
0-2,4,6-8,11,12,14-25,27-33,35-39
Scheme
<lang scheme> (define (make-range start end)
(cond ((= start end)
`("," ,start))
((= end (+ start 1))
`("," ,start "," ,end))
(else
`("," ,start "-" ,end))))
(define (range-extract-0 start end a)
(cond ((null? a)
(make-range start end))
((= (+ 1 end) (car a))
(range-extract-0 start (car a) (cdr a)))
(else
(append (make-range start end)
(range-extract-0 (car a) (car a) (cdr a))))))
(define (range-extract a)
(apply string-append (map (lambda (x)
(if (number? x)
(number->string x)
x))
(cdr (range-extract-0 (car a) (car a) (cdr a))))))
(range-extract '( 0 1 2 4 6 7 8 11 12 14
15 16 17 18 19 20 21 22 23 24
25 27 28 29 30 31 32 33 35 36
37 38 39))
</lang>
- Output:
0-2,4,6-8,11,12,14-25,27-33,35-39
Seed7
<lang seed7>$ include "seed7_05.s7i";
const func string: rangeExtraction (in array integer: numbers) is func
result
var string: rangeStri is "";
local
var integer: index is 1;
var integer: index2 is 1;
begin
while index <= length(numbers) do
while index2 <= pred(length(numbers)) and numbers[succ(index2)] = succ(numbers[index2]) do
incr(index2);
end while;
if succ(index) < index2 then
rangeStri &:= "," <& numbers[index] <& "-" <& numbers[index2];
else
while index <= index2 do
rangeStri &:= "," <& numbers[index];
incr(index);
end while;
end if;
incr(index2);
index := index2;
end while;
rangeStri := rangeStri[2 ..];
end func;
const proc: main is func
begin
writeln(rangeExtraction([] (0, 1, 2, 4, 6, 7, 8, 11, 12, 14, 15, 16, 17, 18, 19,
20, 21, 22, 23, 24, 25, 27, 28, 29, 30, 31, 32, 33, 35, 36, 37, 38, 39)));
end func;</lang>
- Output:
0-2,4,6-8,11,12,14-25,27-33,35-39
SNOBOL4
Handles +/- and negative ranges.
<lang SNOBOL4>* # Absolute value
define('abs(n)') :(abs_end)
abs abs = ~(abs = lt(n,0) -n) n :(return) abs_end
define('rangext(str)d1,d2') :(rangext_end)
rangext num = ('+' | '-' | ) span('0123456789') rxt1 str ',' span(' ') = ' ' :s(rxt1) rxt2 str num . d1 ' ' num . d2 = + d1 ('~,' ? *eq(abs(d2 - d1),1) '~' | ',') d2 :s(rxt2) rxt3 str ('~' | '-') num '~' = '-' :s(rxt3) rxt4 str '~' = ',' :s(rxt4)
rangext = str :(return)
rangext_end
- # Test and display
test = '0, 1, 2, 4, 6, 7, 8, 11, 12, 14, '
+ '15, 16, 17, 18, 19, 20, 21, 22, 23, 24, ' + '25, 27, 28, 29, 30, 31, 32, 33, 35, 36, ' + '37, 38, 39'
output = rangext(test)
end</lang>
- Output:
0-2,4,6-8,11,12,14-25,27-33,35-39
Swift
<lang swift>
func rangesFromInts(ints:[Int]) -> [(Int, Int)] {
var range : (Int, Int)?
var ranges = [(Int, Int)]()
for this in ints {
if let (start, end) = range {
if this == end + 1 {
range = (start, this)
}
else {
ranges.append(range!)
range = (this, this)
}
}
else { range = (this, this) }
}
ranges.append(range!)
return ranges
}
func descriptionFromRanges(ranges:[(Int, Int)]) -> String {
var desc = ""
for (start, end) in ranges {
desc += desc.isEmpty ? "" : ","
if start == end {
desc += "\(start)"
}
else if end == start + 1 {
desc += "\(start),\(end)"
}
else {
desc += "\(start)-\(end)"
}
}
return desc
}
let ex = [-6, -3, -2, -1, 0, 1, 3, 4, 5, 7, 8, 9, 10, 11, 14, 15, 17, 18, 19, 20]
let longer = [0, 1, 2, 4, 6, 7, 8, 11, 12, 14,
15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 27, 28, 29, 30, 31, 32, 33, 35, 36, 37, 38, 39]
descriptionFromRanges(rangesFromInts(ex)) descriptionFromRanges(rangesFromInts(longer))
</lang>
or, using a little Foundation:
<lang swift>
extension NSIndexSet {
var rangesDescription : String {
var out = ""
indexSet.enumerateRangesUsingBlock { range, _ in
let start = range.location
let end = range.location+range.length-1
out += out.isEmpty ? "" : ","
if start == end {
out += "\(start)"
}
else if end == start + 1 {
out += "\(start),\(end)"
}
else {
out += "\(start)-\(end)"
}
}
return out
}
}
let ex = [-6, -3, -2, -1, 0, 1, 3, 4, 5, 7, 8, 9, 10, 11, 14, 15, 17, 18, 19, 20] let longer = [0, 1, 2, 4, 6, 7, 8, 11, 12, 14,
15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 27, 28, 29, 30, 31, 32, 33, 35, 36, 37, 38, 39]
var indexSet = NSMutableIndexSet() ex.map { indexSet.addIndex($0) } indexSet.rangesDescription
var indexSet2 = NSMutableIndexSet() longer.map { indexSet2.addIndex($0) } indexSet2.rangesDescription
</lang>
Tcl
<lang tcl>proc rangeExtract list {
set result [lindex $list 0]
set first [set last [lindex $list 0]]
foreach term [lrange $list 1 end] {
if {$term == $last+1} { set last $term continue } if {$last > $first} { append result [expr {$last == $first+1 ? "," : "-"}] $last } append result "," $term set first [set last $term]
}
if {$last == $first+1} {
append result "," $last
} elseif {$last > $first} {
append result "-" $last
} return $result
}
- Commas already removed so it is a natural Tcl list
puts [rangeExtract {
0 1 2 4 6 7 8 11 12 14 15 16 17 18 19 20 21 22 23 24 25 27 28 29 30 31 32 33 35 36 37 38 39
}]</lang>
- Output:
0-2,4,6-8,11,12,14-25,27-33,35-39
TUSCRIPT
TUSCRIPT has a built-in routine "COMBINE" that combines a range of integers by a dash '-'. It is possible to differ between every range that expands more than two values (6-8), and every range that expands less than two values (11,12 are not combined). <lang tuscript> $$ MODE TUSCRIPT MODE DATA $$ numbers=* 0, 1, 2, 4, 6, 7, 8, 11, 12, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 27, 28, 29, 30, 31, 32, 33, 35, 36, 37, 38, 39 $$ MODE TUSCRIPT numbers=EXCHANGE (numbers,":,><<> :':") unrangednrs=JOIN (numbers,"") rangednrs=COMBINE (unrangednrs,"") rangednrs=EXCHANGE (rangednrs,":':,:") PRINT rangednrs </lang>
- Output:
0-2,4,6-8,11,12,14-25,27-33,35-39
Solution without COMBINE <lang tuscript> $$ MODE TUSCRIPT MODE DATA $$ numbers=* 0, 1, 2, 4, 6, 7, 8, 11, 12, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 27, 28, 29, 30, 31, 32, 33, 35, 36, 37, 38, 39 $$ MODE TUSCRIPT numbers=EXCHANGE (numbers,":,><<> :':") unrangednrs=JOIN (numbers,"")
help = APPEND (unrangednrs, "999999999") rest = REMOVE (help, 1, n_1) n_2 = n_1, n_3= n_2 + 1,rangednrs= "" LOOP n= rest
IF (n!=n_3) THEN
rangednrs = APPEND (rangednrs, n_1)
IF (n_1!=n_2) THEN
range=n_1+1
IF (range==n_2) THEN
rangednrs = APPEND (rangednrs,n_2)
ELSE
rangednrs = CONCAT (rangednrs, "-", n_2)
ENDIF
ENDIF
n_1 = n
ENDIF
n_2 = n, n_3 = n_2 + 1
ENDLOOP rangednrs=EXCHANGE (rangednrs,":':,:") PRINT rangednrs </lang>
- Output:
0-2,4,6-8,11,12,14-25,27-33,35-39
UNIX Shell
<lang bash>#!/usr/bin/bash
range_contract () (
add_range () {
case $(( current - range_start )) in
0) ranges+=( $range_start ) ;;
1) ranges+=( $range_start $current ) ;;
*) ranges+=("$range_start-$current") ;;
esac
}
ranges=() range_start=$1 current=$1 shift
for number; do
if (( number > current+1 )); then
add_range
range_start=$number
fi
current=$number
done
add_range
x="${ranges[@]}"
echo ${x// /,}
)
range_contract 0 1 2 4 6 7 8 11 12 14 15 16 17 18 19 20 21 22 23 24 25 27 28 29 30 31 32 33 35 36 37 38 39</lang>
- Output:
0-2,4,6-8,11,12,14-25,27-33,35-39
Ursala
<lang Ursala>#import std
- import int
x = <0,1,2,4,6,7,8,11,12,14,15,16,17,18,19,20,21,22,23,24,25,27,28,29,30,31,32,33,35,36,37,38,39>
f = mat`,+ ==?(~&l,^|T/~& :/`-)*bhPS+ %zP~~hzX*titZBPiNCSiNCQSL+ rlc ^|E/~& predecessor
- show+
t = <f x></lang>
- Output:
0-2,4,6-8,11,12,14-25,27-33,35-39
VBA
<lang vb> Public Function RangeExtraction(AList) As String 'AList is a variant that is an array, assumed filled with numbers in ascending order Const RangeDelim = "-" 'range delimiter Dim result As String Dim InRange As Boolean Dim Posn, ub, lb, rangestart, rangelen As Integer
result = "" 'find dimensions of AList ub = UBound(AList) lb = LBound(AList) Posn = lb While Posn < ub
rangestart = Posn
rangelen = 0
InRange = True
'try to extend the range
While InRange
rangelen = rangelen + 1
If Posn = ub Then
InRange = False
Else
InRange = (AList(Posn + 1) = AList(Posn) + 1)
Posn = Posn + 1
End If
Wend
If rangelen > 2 Then 'output the range if it has more than 2 elements
result = result & "," & Format$(AList(rangestart)) & RangeDelim & Format$(AList(rangestart + rangelen - 1))
Else 'output the separate elements
For i = rangestart To rangestart + rangelen - 1
result = result & "," & Format$(AList(i))
Next
End If
Posn = rangestart + rangelen
Wend RangeExtraction = Mid$(result, 2) 'get rid of first comma! End Function
Public Sub RangeTest()
'test function RangeExtraction
'first test with a Variant array
Dim MyList As Variant
MyList = Array(0, 1, 2, 4, 6, 7, 8, 11, 12, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 27, 28, 29, 30, 31, 32, 33, 35, 36, 37, 38, 39)
Debug.Print "a) "; RangeExtraction(MyList)
'next test with an array of integers Dim MyOtherList(1 To 20) As Integer MyOtherList(1) = -6 MyOtherList(2) = -3 MyOtherList(3) = -2 MyOtherList(4) = -1 MyOtherList(5) = 0 MyOtherList(6) = 1 MyOtherList(7) = 3 MyOtherList(8) = 4 MyOtherList(9) = 5 MyOtherList(10) = 7 MyOtherList(11) = 8 MyOtherList(12) = 9 MyOtherList(13) = 10 MyOtherList(14) = 11 MyOtherList(15) = 14 MyOtherList(16) = 15 MyOtherList(17) = 17 MyOtherList(18) = 18 MyOtherList(19) = 19 MyOtherList(20) = 20 Debug.Print "b) "; RangeExtraction(MyOtherList) End Sub </lang>
- Output:
RangeTest a) 0-2,4,6-8,11,12,14-25,27-33,35-39 b) -6,-3-1,3-5,7-11,14,15,17-20
VBScript
<lang vb>Function Range_Extraction(list) num = Split(list,",") For i = 0 To UBound(num) startnum = CInt(num(i)) sum = startnum Do While i <= UBound(num) If sum = CInt(num(i)) Then If i = UBound(num) Then If startnum <> CInt(num(i)) Then If startnum + 1 = CInt(num(i)) Then Range_Extraction = Range_Extraction & startnum & "," & num(i) & "," Else Range_Extraction = Range_Extraction & startnum & "-" & num(i) & "," End If Else Range_Extraction = Range_Extraction & startnum & "," End If
Exit Do
Else i = i + 1 sum = sum + 1 End If Else If startnum = CInt(num(i-1)) Then Range_Extraction = Range_Extraction & startnum & "," Else If startnum + 1 = CInt(num(i-1)) Then Range_Extraction = Range_Extraction & startnum & "," & num(i-1) & "," Else Range_Extraction = Range_Extraction & startnum & "-" & num(i-1) & "," End If End If i = i - 1 Exit Do End If Loop Next Range_Extraction = Left(Range_Extraction,Len(Range_Extraction)-1) End Function
WScript.StdOut.Write Range_Extraction("0,1,2,4,6,7,8,11,12,14,15,16,17,18,19,20,21,22,23,24,25,27,28,29,30,31,32,33,35,36,37,38,39")</lang>
- Output:
0-2,4,6-8,11,12,14-25,27-33,35-39
zkl
<lang zkl>fcn range(ns){
fcn(w){
if (w.atEnd) return(Void.Stop);
a:=b:=w.next(); n:=0;
while(b+1 == (c:=w.peekN(n))){ n+=1; b=c }
if(n>1){do(n){w.next()}; return("%d-%d".fmt(a,b)); }
a
} :
(0).pump(*,List,_.fp(ns.walker().tweak(Void,Void))).concat(",");
}</lang> The trick here is to use a modified iterator, one that can look past the end of the sequence without puking. The function gathers three or more successive ints (saved as a "a-b" string list element) or just returns the first one (as a number) if it can't. The resulting list is converted to strings separated by commas. <lang zkl>var ns=T(-6,-3,-2,-1,0,1,3,4,5,7,8,9,10,11,14,15,17,18,19,20); range(ns).println();
ns=T(
0, 1, 2, 4, 6, 7, 8, 11, 12, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 27, 28, 29, 30, 31, 32, 33, 35, 36, 37, 38, 39);
range(ns).println();
range([1..100]).println();</lang>
- Output:
-6,-3-1,3-5,7-11,14,15,17-20 0-2,4,6-8,11,12,14-25,27-33,35-39 1-100
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