Range expansion

From Rosetta Code
Task
Range expansion
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).


Task

Expand the range description:

  -6,-3--1,3-5,7-11,14,15,17-20 

Note that the second element above, is the range from minus 3 to minus 1.


Related task



Ada[edit]

The function Expand takes a string and returns a corresponding array of integers. Upon syntax errors Constraint_Error is propagated:

with Ada.Text_IO; use Ada.Text_IO;
procedure Test_Range_Expansion is
type Sequence is array (Positive range <>) of Integer;
function Expand (Text : String) return Sequence is
To  : Integer := Text'First;
Count : Natural := 0;
Low  : Integer;
function Get return Integer is
From : Integer := To;
begin
if Text (To) = '-' then
To := To + 1;
end if;
while To <= Text'Last loop
case Text (To) is
when ',' | '-' => exit;
when others => To := To + 1;
end case;
end loop;
return Integer'Value (Text (From..To - 1));
end Get;
begin
while To <= Text'Last loop -- Counting items of the list
Low := Get;
if To > Text'Last or else Text (To) = ',' then
Count := Count + 1;
else
To := To + 1;
Count := Count + Get - Low + 1;
end if;
To := To + 1;
end loop;
return Result : Sequence (1..Count) do
Count := 0;
To := Text'First;
while To <= Text'Last loop -- Filling the list
Low := Get;
if To > Text'Last or else Text (To) = ',' then
Count := Count + 1;
Result (Count) := Low;
else
To := To + 1;
for Item in Low..Get loop
Count := Count + 1;
Result (Count) := Item;
end loop;
end if;
To := To + 1;
end loop;
end return;
end Expand;
procedure Put (S : Sequence) is
First : Boolean := True;
begin
for I in S'Range loop
if First then
First := False;
else
Put (',');
end if;
Put (Integer'Image (S (I)));
end loop;
end Put;
begin
Put (Expand ("-6,-3--1,3-5,7-11,14,15,17-20"));
end Test_Range_Expansion;
Output:
-6,-3,-2,-1, 3, 4, 5, 7, 8, 9, 10, 11, 14, 15, 17, 18, 19, 20

ALGOL 68[edit]

Works with: ALGOL 68 version Revision 1 - no extensions to language used
Works with: ALGOL 68G version Any - tested with release 1.18.0-9h.tiny - string parsing and formatting code tested with 2.6.win32
Works with: ELLA ALGOL 68 version Any (with appropriate job cards) - tested with release 1.8-8d
MODE YIELDINT = PROC(INT)VOID;
 
MODE RANGE = STRUCT(INT lwb, upb);
MODE RANGEINT = UNION(RANGE, INT);
 
OP SIZEOF = ([]RANGEINT list)INT: (
# determine the length of the output array #
INT upb := LWB list - 1;
FOR key FROM LWB list TO UPB list DO
CASE list[key] IN
(RANGE value): upb +:= upb OF value - lwb OF value + 1,
(INT): upb +:= 1
ESAC
OD;
upb
);
 
PROC gen range expand = ([]RANGEINT list, YIELDINT yield)VOID:
FOR key FROM LWB list TO UPB list DO
CASE list[key] IN
(RANGE range): FOR value FROM lwb OF range TO upb OF range DO yield(value) OD,
(INT int): yield(int)
ESAC
OD;
 
PROC range expand = ([]RANGEINT list)[]INT: (
[LWB list: LWB list + SIZEOF list - 1]INT out;
INT upb := LWB out - 1;
# FOR INT value IN # gen range expand(list, # ) DO #
## (INT value)VOID:
out[upb +:= 1] := value
# OD #);
out
);
 
#
test:(
[]RANGEINT list = (-6, RANGE(-3, -1), RANGE(3, 5), RANGE(7, 11), 14, 15, RANGE(17, 20));
print((range expand(list), new line))
)
#

 
 
# converts string containing a comma-separated list of ranges and values to a []RANGEINT #
OP TORANGE = ( STRING s )[]RANGEINT:
BEGIN
 
# counts the number of elements - one more than the number of commas #
# and so assumes there is always at least one element #
PROC count elements = INT:
BEGIN
 
INT elements := 1;
 
FOR pos FROM LWB s TO UPB s
DO
IF s[ pos ] = ","
THEN
elements +:= 1
FI
OD;
 
# RESULT #
elements
END; # count elements #
 
REF[]RANGEINT result = HEAP [ 1 : count elements ]RANGEINT;
 
# does the actual parsing - assumes the string is syntatically valid and doesn't check for errors #
# - in particular, a string with no elements will cause problems, as will space characters in the string #
PROC parse range string = []RANGEINT:
BEGIN
 
INT element := 0;
INT str pos := 1;
 
PROC next = VOID: str pos +:= 1;
PROC curr char = CHAR: IF str pos > UPB s THEN "?" ELSE s[ str pos ] FI;
PROC have minus = BOOL: curr char = "-";
PROC have digit = BOOL: curr char >= "0" AND curr char <= "9";
 
 
# parses a number out of the string #
# the number must be a sequence of digits with an optional leading minus sign #
PROC get number = INT:
BEGIN
 
INT number := 0;
 
INT sign multiplier = IF have minus
THEN
# negaive number #
# skip the sign #
next;
-1
ELSE
# positive number #
1
FI;
 
WHILE curr char >= "0" AND curr char <= "9"
DO
number *:= 10;
number +:= ( ABS curr char - ABS "0" );
next
OD;
 
# RESULT #
number * sign multiplier
END; # get number #
 
 
# main parsing #
WHILE str pos <= UPB s
DO
CHAR c = curr char;
 
IF have minus OR have digit
THEN
# have the start of a number #
INT from value = get number;
element +:= 1;
IF NOT have minus
THEN
# not a range #
result[ element ] := from value
ELSE
# have a range #
next;
INT to value = get number;
result[ element ] := RANGE( from value, to value )
FI
ELSE
# should be a comma #
next
FI
OD;
 
# RESULT #
result
END; # parse range string #
 
 
# RESULT #
parse range string
END; # TORANGE #
 
 
# converts a []INT to a comma separated string of the elements #
OP TOSTRING = ( []INT values )STRING:
BEGIN
 
STRING result := "";
STRING separator := "";
 
FOR pos FROM LWB values TO UPB values
DO
result +:= ( separator + whole( values[ pos ], 0 ) );
separator := ","
OD;
 
# RESULT #
result
END; # TOSTRING #
 
 
test:(
print( ( TOSTRING range expand( TORANGE "-6,-3--1,3-5,7-11,14,15,17-20" ), newline ) )
)
 
Output:
-6,-3,-2,-1,3,4,5,7,8,9,10,11,14,15,17,18,19,20


AppleScript[edit]

Translation of: JavaScript
(Functional ES5 version)


on run
 
expansion("-6,-3--1,3-5,7-11,14,15,17-20")
 
end run
 
 
-- Each comma-delimited string is mapped to a list of integers,
-- and these integer lists are concatenated together into a single list
 
-- expansion :: String -> [Int]
on expansion(strExpr)
concatMap(my signedRange, splitOn(",", strExpr))
end expansion
 
 
-- The string (between commas) is split on hyphens,
-- and this segmentation is rewritten to ranges or minus signs
-- and evaluated to lists of integer values
 
-- signedRange :: String -> [Int]
on signedRange(strHyphenated)
range(foldl(my signedIntegerAppended, {}, ¬
splitOn("-", strHyphenated)))
end signedRange
 
 
-- After the first character, numbers preceded by an
-- empty string (resulting from splitting on hyphens)
-- and interpreted as negative
 
-- signedIntegerAppended:: [Int] -> String -> Int -> [Int] -> [Int]
on signedIntegerAppended(lstAccumulator, strNum, iPosn, lst)
if strNum ≠ "" then
if iPosn > 1 then
if length of (item (iPosn - 1) of lst) > 0 then
set strSign to ""
else
set strSign to "-"
end if
else
set strSign to "+"
end if
lstAccumulator & ((strSign & strNum) as integer)
else
lstAccumulator
end if
end signedIntegerAppended
 
 
 
 
-- GENERIC LIBRARY FUNCTIONS
 
-- splitOn :: Text -> Text -> [Text]
on splitOn(strDelim, strMain)
set {dlm, my text item delimiters} to {my text item delimiters, strDelim}
set lstParts to text items of strMain
set my text item delimiters to dlm
return lstParts
end splitOn
 
-- range :: (Int, Int) -> [Int]
on range(tuple)
if tuple = {} then return {}
if length of tuple > 1 then
set {m, n} to tuple
else
return item 1 of tuple
end if
set lng to (n - m) + 1
set base to m - 1
set lst to {}
repeat with i from 1 to lng
set end of lst to i + base
end repeat
return lst
end range
 
-- Higher order functions
 
-- concatMap :: (a -> [b]) -> [a] -> [b]
on concatMap(f, xs)
script mf
on append(a, b)
a & b
end append
end script
foldl(mf's append, {}, map(f, xs))
end concatMap
 
-- map :: (a -> b) -> [a] -> [b]
on map(f, xs)
set mf to mReturn(f)
set lng to length of xs
set lst to {}
repeat with i from 1 to lng
set end of lst to mf's lambda(item i of xs, i, xs)
end repeat
return lst
end map
 
-- foldl :: (a -> b -> a) -> a -> [b] -> a
on foldl(f, startValue, xs)
set mf to mReturn(f)
 
set v to startValue
set lng to length of xs
repeat with i from 1 to lng
set v to mf's lambda(v, item i of xs, i, xs)
end repeat
return v
end foldl
 
 
-- Lift 2nd class handler function into 1st class script wrapper
-- mReturn :: Handler -> Script
on mReturn(f)
if class of f is script then return f
script
property lambda : f
end script
end mReturn


Output:
{-6, -3, -2, -1, 3, 4, 5, 7, 8, 9, 10, 11, 14, 15, 17, 18, 19, 20}

AutoHotkey[edit]

msgbox % expand("-6,-3--1,3-5,7-11,14,15,17-20")
 
expand( range ) {
p := 0
while p := RegExMatch(range, "\s*(-?\d++)(?:\s*-\s*(-?\d++))?", f, p+1+StrLen(f))
loop % (f2 ? f2-f1 : 0) + 1
ret .= "," (A_Index-1) + f1
return SubStr(ret, 2)
}

AWK[edit]

#!/usr/bin/awk -f
BEGIN { FS=","; }
 
{ s="";
for (i=1; i<=NF; i++) { expand($i); }
print substr(s,2);
}
 
function expand(a) {
idx = match(a,/[0-9]-/);
if (idx==0) {
s = s","a;
return;
}
 
start= substr(a,1, idx)+0;
stop = substr(a,idx+2)+0;
for (m = start; m <= stop; m++) {
s = s","m;
}
return;
}
Usage: 
  echo -6,-3--1,3-5,7-11,14,15,17-20  | gawk -f ./range_expansion.awk 
  -6,-3,-2,-1,3,4,5,7,8,9,10,11,14,15,17,18,19,20

BBC BASIC[edit]

      PRINT FNrangeexpand("-6,-3--1,3-5,7-11,14,15,17-20")
END
 
DEF FNrangeexpand(r$)
LOCAL i%, j%, k%, t$
REPEAT
i% = INSTR(r$, "-", i%+1)
IF i% THEN
j% = i%
WHILE MID$(r$,j%-1,1)<>"," AND j%<>1
j% -= 1
ENDWHILE
IF i%>j% IF MID$(r$,j%,i%-j%)<>STRING$(i%-j%," ") THEN
t$ = ""
FOR k% = VALMID$(r$,j%) TO VALMID$(r$,i%+1)-1
t$ += STR$(k%) + ","
NEXT
r$ = LEFT$(r$,j%-1) + t$ + MID$(r$,i%+1)
i% = j% + LEN(t$) + 2
ENDIF
ENDIF
UNTIL i% = 0
= r$
Output:
-6,-3,-2,-1,3,4,5,7,8,9,10,11,14,15,17,18,19,20

Bracmat[edit]

  ( expandRanges
= a b L
. @( !arg
 : (#(?a:?b)|#?a "-" #?b)
(:?L|"," [%(expandRanges$!sjt:?L))
)
& whl
' ( (!L:&!b|(!b,!L))
 : ?L
& -1+!b:~<!a:?b
)
& !L
|
)
& out$(str$(expandRanges$"-6,-3--1,3-5,7-11,14,15,17-20"))
 
Output:
-6,-3,-2,-1,3,4,5,7,8,9,10,11,14,15,17,18,19,20

C[edit]

Recursive descent parser.

#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
 
/* BNFesque
rangelist := (range | number) [',' rangelist]
range := number '-' number */

 
int get_list(const char *, char **);
int get_rnge(const char *, char **);
 
/* parser only parses; what to do with parsed items is up to
* the add_number and and_range functions */

void add_number(int x);
int add_range(int x, int y);
 
#define skip_space while(isspace(*s)) s++
#define get_number(x, s, e) (x = strtol(s, e, 10), *e != s)
int get_list(const char *s, char **e)
{
int x;
while (1) {
skip_space;
if (!get_rnge(s, e) && !get_number(x, s, e)) break;
s = *e;
 
skip_space;
if ((*s) == '\0') { putchar('\n'); return 1; }
if ((*s) == ',') { s++; continue; }
break;
}
*(const char **)e = s;
printf("\nSyntax error at %s\n", s);
return 0;
}
 
int get_rnge(const char *s, char **e)
{
int x, y;
char *ee;
if (!get_number(x, s, &ee)) return 0;
s = ee;
 
skip_space;
if (*s != '-') {
*(const char **)e = s;
return 0;
}
s++;
if(!get_number(y, s, e)) return 0;
return add_range(x, y);
}
 
void add_number(int x)
{
printf("%d ", x);
}
 
int add_range(int x, int y)
{
if (y <= x) return 0;
while (x <= y) printf("%d ", x++);
return 1;
}
 
int main()
{
char *end;
 
/* this is correct */
if (get_list("-6,-3--1,3-5,7-11,14,15,17-20", &end)) puts("Ok");
 
/* this is not. note the subtle error: "-6 -3" is parsed
* as range(-6, 3), so synax error comes after that */

get_list("-6 -3--1,3-5,7-11,14,15,17-20", &end);
 
return 0;
}
Output:
-6 -3 -2 -1 3 4 5 7 8 9 10 11 14 15 17 18 19 20 
Ok
-6 -5 -4 -3 -2 -1 0 1 2 3 
Syntax error at --1,3-5,7-11,14,15,17-20

C#[edit]

Works with: C sharp version 3.0
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text.RegularExpressions;
 
class Program
{
static void Main(string[] args)
{
var rangeString = "-6,-3--1,3-5,7-11,14,15,17-20";
var matches = Regex.Matches(rangeString, @"(?<f>-?\d+)-(?<s>-?\d+)|(-?\d+)");
var values = new List<string>();
 
foreach (var m in matches.OfType<Match>())
{
if (m.Groups[1].Success)
{
values.Add(m.Value);
continue;
}
 
var start = Convert.ToInt32(m.Groups["f"].Value);
var end = Convert.ToInt32(m.Groups["s"].Value) + 1;
 
values.AddRange(Enumerable.Range(start, end - start).Select(v => v.ToString()));
}
 
Console.WriteLine(string.Join(", ", values));
}
}
Works with: C sharp version 3.5+
using System;
using System.Collections.Generic;
using System.Linq;
 
namespace RangeExpansion {
internal static class StringExtensions {
internal static IEnumerable<int> ExpandRange(this string s) {
return s.Split(',')
.Select(rstr => {
int start;
if (int.TryParse(rstr, out start))
return new {Start = start, End = start};
var istr = new string(("+-".Any(_ => rstr[0] == _)
? rstr.Take(1).Concat(rstr.Skip(1).TakeWhile(char.IsDigit))
: rstr.TakeWhile(char.IsDigit)
).ToArray());
rstr = rstr.Substring(istr.Length + 1, (rstr.Length - istr.Length) - 1);
return new {Start = int.Parse(istr), End = int.Parse(rstr)};
}).SelectMany(_ => Enumerable.Range(_.Start, _.End - _.Start + 1));
}
}
 
internal static class Program {
private static void Main() {
const string RANGE_STRING = "-6,-3--1,3-5,7-11,14,15,17-20";
var values = RANGE_STRING.ExpandRange().ToList();
var vstr = string.Join(", ", values.Select(_ => _.ToString()));
Console.WriteLine(vstr);
}
}
}

C++[edit]

#include <iostream>
#include <sstream>
#include <iterator>
#include <climits>
#include <deque>
 
// parse a list of numbers with ranges
//
// arguments:
// is: the stream to parse
// out: the output iterator the parsed list is written to.
//
// returns true if the parse was successful. false otherwise
template<typename OutIter>
bool parse_number_list_with_ranges(std::istream& is, OutIter out)
{
int number;
// the list always has to start with a number
while (is >> number)
{
*out++ = number;
 
char c;
if (is >> c)
switch(c)
{
case ',':
continue;
case '-':
{
int number2;
if (is >> number2)
{
if (number2 < number)
return false;
while (number < number2)
*out++ = ++number;
char c2;
if (is >> c2)
if (c2 == ',')
continue;
else
return false;
else
return is.eof();
}
else
return false;
}
default:
return is.eof();
}
else
return is.eof();
}
// if we get here, something went wrong (otherwise we would have
// returned from inside the loop)
return false;
}
 
int main()
{
std::istringstream example("-6,-3--1,3-5,7-11,14,15,17-20");
std::deque<int> v;
bool success = parse_number_list_with_ranges(example, std::back_inserter(v));
if (success)
{
std::copy(v.begin(), v.end()-1,
std::ostream_iterator<int>(std::cout, ","));
std::cout << v.back() << "\n";
}
else
std::cout << "an error occured.";
}
Output:
-6,-3,-2,-1,3,4,5,7,8,9,10,11,14,15,17,18,19,20

Clojure[edit]

There is a split method in clojure.contrib, but I don't know if it is able to skip first character to so that (split "-8--8") => (-8 -8).

(defn split [s sep]
(defn skipFirst [[x & xs :as s]]
(cond (empty? s) [nil nil]
(= x sep) [x xs]
true [nil s]))
(loop [lst '(), s s]
(if (empty? s) (reverse lst)
(let [[hd trunc] (skipFirst s)
[word news] (split-with #(not= % sep) trunc)
cWord (cons hd word)]
(recur (cons (apply str cWord) lst)
(apply str (rest news)))))))
 
(defn parseRange [[x & xs :as s]]
(if (some #(= % \-) xs)
(let [[r0 r1] (split s \-)]
(range (read-string r0) (inc (read-string r1))))
(list (read-string (str s))))))
 
(defn rangeexpand [s]
(flatten (map parseRange (split s \,))))
 
> (rangeexpand "-6,-3--1,3-5,7-11,14,15,17-20")
(-6 -3 -2 -1 3 4 5 7 8 9 10 11 14 15 17 18 19 20)

COBOL[edit]

Works with: GNU Cobol version 2.0
       >>SOURCE FREE
IDENTIFICATION DIVISION.
PROGRAM-ID. expand-range.
 
DATA DIVISION.
WORKING-STORAGE SECTION.
01 comma-pos PIC 99 COMP VALUE 1.
01 dash-pos PIC 99 COMP.
01 end-num PIC S9(3).
01 Max-Part-Len CONSTANT 10.
01 num PIC S9(3).
01 edited-num PIC -(3)9.
01 part PIC X(10).
 
01 part-flag PIC X.
88 last-part VALUE "Y".
 
01 range-str PIC X(80).
01 Range-Str-Len CONSTANT 80.
01 start-pos PIC 99 COMP.
01 start-num PIC S9(3).
 
PROCEDURE DIVISION.
ACCEPT range-str
 
PERFORM WITH TEST AFTER UNTIL last-part
UNSTRING range-str DELIMITED BY "," INTO part WITH POINTER comma-pos
PERFORM check-if-last
 
PERFORM find-range-dash
 
IF dash-pos > Max-Part-Len
PERFORM display-num
ELSE
PERFORM display-range
END-IF
END-PERFORM
 
DISPLAY SPACES
 
GOBACK
.
check-if-last SECTION.
IF comma-pos > Range-Str-Len
SET last-part TO TRUE
END-IF
.
find-range-dash SECTION.
IF part (1:1) <> "-"
MOVE 1 TO start-pos
ELSE
MOVE 2 TO start-pos
END-IF
 
MOVE 1 TO dash-pos
INSPECT part (start-pos:) TALLYING dash-pos FOR CHARACTERS BEFORE "-"
COMPUTE dash-pos = dash-pos + start-pos - 1
.
display-num SECTION.
MOVE part TO edited-num
CALL "display-edited-num" USING CONTENT part-flag, edited-num
.
display-range SECTION.
MOVE part (1:dash-pos - 1) TO start-num
MOVE part (dash-pos + 1:) TO end-num
 
PERFORM VARYING num FROM start-num BY 1 UNTIL num = end-num
MOVE num TO edited-num
CALL "display-edited-num" USING CONTENT "N", edited-num
END-PERFORM
 
MOVE end-num TO edited-num
CALL "display-edited-num" USING CONTENT part-flag, edited-num
.
END PROGRAM expand-range.
 
 
IDENTIFICATION DIVISION.
PROGRAM-ID. display-edited-num.
 
DATA DIVISION.
LINKAGE SECTION.
01 hide-comma-flag PIC X.
88 hide-comma VALUE "Y".
01 edited-num PIC -(3)9.
 
PROCEDURE DIVISION USING hide-comma-flag, edited-num.
DISPLAY FUNCTION TRIM(edited-num) NO ADVANCING
IF NOT hide-comma
DISPLAY ", " NO ADVANCING
END-IF
.
END PROGRAM display-edited-num.

Setup:

 
$ ./expand-range 
-6,-3--1,3-5,7-11,14,15,17-20
Output:
-6, -3, -2, -1, 3, 4, 5, 7, 8, 9, 10, 11, 14, 15, 17, 18, 19, 20

Common Lisp[edit]

(defun expand-ranges (string)
(loop
with prevnum = nil
for idx = 0 then (1+ nextidx)
for (number nextidx) = (multiple-value-list
(parse-integer string
:start idx :junk-allowed t))
append (cond
(prevnum
(prog1
(loop for i from prevnum to number
collect i)
(setf prevnum nil)))
((and (< nextidx (length string))
(char= (aref string nextidx) #\-))
(setf prevnum number)
nil)
(t
(list number)))
while (< nextidx (length string))))
 
CL-USER> (expand-ranges "-6,-3--1,3-5,7-11,14,15,17-20")
(-6 -3 -2 -1 3 4 5 7 8 9 10 11 14 15 17 18 19 20)

D[edit]

import std.stdio, std.regex, std.conv, std.range, std.algorithm;
 
enum rangeEx = (string s) /*pure*/ => s.matchAll(`(-?\d+)-?(-?\d+)?,?`)
.map!q{ a[1].to!int.iota(a[1 + !a[2].empty].to!int + 1) }.join;
 
void main() {
"-6,-3--1,3-5,7-11,14,15,17-20".rangeEx.writeln;
}
Output:
[-6, -3, -2, -1, 3, 4, 5, 7, 8, 9, 10, 11, 14, 15, 17, 18, 19, 20]

EchoLisp[edit]

 
;; parsing [spaces][-]digit(s)-[-]digit(s)[spaces]
(define R (make-regexp "^ *(\-?\\d+)\-(\-?\\d+) *$" ))
 
;; the native (range a b) is [a ... b[
;; (range+ a b) is [a ... b]
(define (range+ a b)
(if (< a b) (range a (1+ b))
(if (> a b) (range a (1- b) -1)
(list a))))
 
;; in : string : "number" or "number-number"
;; out : a range = list of integer(s)
(define (do-range str)
(define from-to (regexp-exec R str)) ;; "1-3" --> ("1" "3")
(if from-to
(range+ (string->number (first from-to)) (string->number (second from-to)))
(list (string->number str))))
 
(define (ranges str)
(apply append (map do-range (string-split str ","))))
 
 
(define task "-6,-3--1,3-5,7-11,14,15,17-20")
(ranges task)
(-6 -3 -2 -1 3 4 5 7 8 9 10 11 14 15 17 18 19 20)
 

Elixir[edit]

Translation of: Ruby
defmodule RC do
def expansion(range) do
Enum.flat_map(String.split(range, ","), fn part ->
case Regex.scan(~r/^(-?\d+)-(-?\d+)$/, part) do
[[_,a,b]] -> Enum.to_list(String.to_integer(a) .. String.to_integer(b))
[] -> [String.to_integer(part)]
end
end)
end
end
 
IO.inspect RC.expansion("-6,-3--1,3-5,7-11,14,15,17-20")
Output:
[-6, -3, -2, -1, 3, 4, 5, 7, 8, 9, 10, 11, 14, 15, 17, 18, 19, 20]

Erlang[edit]

 
-module( range ).
 
-export( [expansion/1, task/0] ).
 
expansion( String ) ->
lists:flatten( [expansion_individual(io_lib:fread("~d", X)) || X <- string:tokens(String, ",")] ).
 
task() ->
io:fwrite( "~p~n", [expansion("-6,-3--1,3-5,7-11,14,15,17-20")] ).
 
 
 
expansion_individual( {ok, [N], []} ) -> N;
expansion_individual( {ok, [Start], "-" ++ Stop_string} ) -> lists:seq( Start, erlang:list_to_integer(Stop_string) ).
 
Output:
34> range:task().
[-6,-3,-2,-1,3,4,5,7,8,9,10,11,14,15,17,18,19,20]

Forth[edit]

: >snumber ( str len -- 'str 'len n )
0. 2swap
over c@ [char] - = if
1 /string
>number 2swap drop
negate
else
>number 2swap drop
then ;
 
: expand ( str len -- )
begin dup while
>snumber >r
dup if over c@ [char] - = if
1 /string
>snumber r> over >r
do i . loop
then then
dup if over c@ [char] , = if
1 /string
then then
r> .
repeat 2drop ;
 
s" -6,-3--1,3-5,7-11,14,15,17-20" expand

Fortran[edit]

In order to save on the annoyance of having to declare the type of function ERANGE in each routine that invokes it (just one, here), the F90 MODULE protocol is convenient. F90 also allows for routines to contain service routines that share the context without massive parameter lists or shared COMMON areas, though alternatively, the shared variables could be inside the MODULE which would contain the service routines as separate routines also inside the module. But for this, one should not share variables having short names such as I. Otherwise, this would be F77 style except for the usage of the I0 format code in subroutine SPLOT. If that were unavailable, code I12 could be used and leading spaces would have to be skipped instead. The DO WHILE loop with its EXIT and labels would have to be less decorative for F77.

The standard problem of "How long is a piece of string?" applies yet again. Arrays and character variables have to be declared with some fixed size, and the usual approach is "surely big enough". The test input is not a problem, because the caller can use the needed size and pass that to ERANGE as a parameter, whatever its size. But function ERANGE's result must have some pre-declared size, and for this example, CHARACTER*200 will do. Via a great deal of blather, varying-size character variables can be defined and used in F90/95, and F2003 has standardised a method of doing this, whereby whenever something like ALINE = ALINE // "stuff" is executed, variable ALINE is reallocated with additional space. This involves copying the old content to the newly allocated larger storage area, so doing a lot of this would be bad snowballing.

The method is to grind through the input string expecting to find a number or a number - number pair (signed numbers allowed), followed by a comma if more is to follow. The state of the scan is represented by position within the scanning code rather than mess with state variables, so it is convenient to have service routines for the resulting repetition of basic actions. No checks are made for improper input, for instance a string ending with a comma. Those of a delicate disposition may be troubled by functions that don't just return a result but also mess with their parameter and change their environment. Here, the results from the functions assist with the flow of control through the scan, it is the side effects that manipulate the data.

A frustrating problem with many modern computer languages is the absence of a "shortcut" evaluation praxis for logical expressions; in Fortran's case the modern standard is that there is no standard. So a test I<=LEN(TEXT) & TEXT(I:I)etc. can't be relied upon to dodge out-of-bounds errors, and a flabby two-statement sequence is required instead. Similarly, few Fortran compilers allow for a function being evaluated via a WRITE statement to itself succeed in using a WRITE statement internally, though some do if one usage is free-format and the other formatted. If necessary, subroutine SPLOT could be re-written to convert an integer to a digit string without a WRITE statement, even for negative integers. And some compilers have difficulty with the use of the function name as a variable within the function so that it is safest to develop the result in an ordinary variable and then remember to assign its value to the function name just before exit.

A single number is made internally into a two-number range sequence, which values are used as the bounds for a DO-loop to generate the numbers for output. Despite the The range syntax is to be used only for, and for every range that expands to more than two values, I see no reason for this restriction (say because otherwise some fancy method would be stymied, except I can think of no such fancier method) and I have no desire to interpose some sort of error message, a tedious business that requires a wider interface between a routine and its caller. Similarly, if a range of 40-30 were to appear, why not take it at face value?
      MODULE HOMEONTHERANGE
CONTAINS !The key function.
CHARACTER*200 FUNCTION ERANGE(TEXT) !Expands integer ranges in a list.
Can't return a character value of variable size.
CHARACTER*(*) TEXT !The list on input.
CHARACTER*200 ALINE !Scratchpad for output.
INTEGER N,N1,N2 !Numbers in a range.
INTEGER I,I1 !Steppers.
ALINE = "" !Scrub the scratchpad.
L = 0 !No text has been placed.
I = 1 !Start at the start.
CALL FORASIGN !Find something to look at.
Chug through another number or number - number range.
R:DO WHILE(EATINT(N1)) !If I can grab a first number, a term has begun.
N2 = N1 !Make the far end the same.
IF (PASSBY("-")) CALL EATINT(N2) !A hyphen here is not a minus sign.
IF (L.GT.0) CALL EMIT(",") !Another, after what went before?
DO N = N1,N2,SIGN(+1,N2 - N1) !Step through the range, possibly backwards.
CALL SPLOT(N) !Roll a number.
IF (N.NE.N2) CALL EMIT(",") !Perhaps another follows.
END DO !On to the next number.
IF (.NOT.PASSBY(",")) EXIT R !More to come?
END DO R !So much for a range.
Completed the scan. Just return the result.
ERANGE = ALINE(1:L) !Present the result. Fiddling ERANGE is bungled by some compilers.
CONTAINS !Some assistants for the scan to save on repetition and show intent.
SUBROUTINE FORASIGN !Look for one.
1 IF (I.LE.LEN(TEXT)) THEN !After a thingy,
IF (TEXT(I:I).LE." ") THEN !There may follow spaces.
I = I + 1 !So,
GO TO 1 !Speed past any.
END IF !So that the caller can see
END IF !Whatever substantive character follows.
END SUBROUTINE FORASIGN !Simple enough.
 
LOGICAL FUNCTION PASSBY(C) !Advances the scan if a certain character is seen.
Could consider or ignore case for letters, but this is really for single symbols.
CHARACTER*1 C !The character.
PASSBY = .FALSE. !Pessimism.
IF (I.LE.LEN(TEXT)) THEN !Can't rely on I.LE.LEN(TEXT) .AND. TEXT(I:I)...
IF (TEXT(I:I).EQ.C) THEN !Curse possible full evaluation.
PASSBY = .TRUE. !Righto, C is seen.
I = I + 1 !So advance the scan.
CALL FORASIGN !And see what follows.
END IF !So much for a match.
END IF !If there is something to be uinspected.
END FUNCTION PASSBY !Can't rely on testing PASSBY within PASSBY either.
 
LOGICAL FUNCTION EATINT(N) !Convert text into an integer.
INTEGER N !The value to be ascertained.
INTEGER D !A digit.
LOGICAL NEG !In case of a minus sign.
EATINT = .FALSE. !Pessimism.
IF (I.GT.LEN(TEXT)) RETURN !Anything to look at?
N = 0 !Scrub to start with.
IF (PASSBY("+")) THEN !A plus sign here can be ignored.
NEG = .FALSE. !So, there's no minus sign.
ELSE !And if there wasn't a plus,
NEG = PASSBY("-") !A hyphen here is a minus sign.
END IF !One way or another, NEG is initialised.
IF (I.GT.LEN(TEXT)) RETURN !Nothing further! We wuz misled!
Chug through digits. Can develop -2147483648, thanks to the workings of two's complement.
10 D = ICHAR(TEXT(I:I)) - ICHAR("0") !Hope for a digit.
IF (0.LE.D .AND. D.LE.9) THEN !Is it one?
N = N*10 + D !Yes! Assimilate it, negatively.
I = I + 1 !Advance one.
IF (I.LE.LEN(TEXT)) GO TO 10 !And see what comes next.
END IF !So much for a sequence of digits.
IF (NEG) N = -N !Apply the minus sign.
EATINT = .TRUE. !Should really check for at least one digit.
CALL FORASIGN !Ram into whatever follows.
END FUNCTION EATINT !Integers are easy. Could check for no digits seen.
 
SUBROUTINE EMIT(C) !Rolls forth one character.
CHARACTER*1 C !The character.
L = L + 1 !Advance the finger.
IF (L.GT.LEN(ALINE)) STOP "Ran out of ALINE!" !Maybe not.
ALINE(L:L) = C !And place the character.
END SUBROUTINE EMIT !That was simple.
 
SUBROUTINE SPLOT(N) !Rolls forth a signed number.
INTEGER N !The number.
CHARACTER*12 FIELD !Sufficient for 32-bit integers.
INTEGER I !A stepper.
WRITE (FIELD,"(I0)") N !Roll the number, with trailing spaces.
DO I = 1,12 !Now transfer the ALINE of the number.
IF (FIELD(I:I).LE." ") EXIT !Up to the first space.
CALL EMIT(FIELD(I:I)) !One by one.
END DO !On to the end.
END SUBROUTINE SPLOT !Not so difficult either.
END FUNCTION ERANGE !A bit tricky.
END MODULE HOMEONTHERANGE
 
PROGRAM POKE
USE HOMEONTHERANGE
CHARACTER*(200) SOME
SOME = "-6,-3--1,3-5,7-11,14,15,17-20"
SOME = ERANGE(SOME)
WRITE (6,*) SOME !If ERANGE(SOME) then the function usually can't write output also.
END
Output:
 -6,-3,-2,-1,3,4,5,7,8,9,10,11,14,15,17,18,19,20

A check by using -2147483648 showed that EATINT develops the correct value even if N is built positively. Adding 8 to 2147483640 VIA N = N*10 + D indeed produces -2147483648 (and NEG was t), but the IF (NEG) N = -N still results in -2147483648 because of the working of (flip all bits and add one): invert(-2147483648) = 2147483647, and, adding one to that produces -2147483648.

F#[edit]

open System.Text.RegularExpressions
 
// simplify regex matching with an active pattern
let (|Regexp|_|) pattern txt =
match Regex.Match(txt, pattern) with
| m when m.Success -> [for g in m.Groups -> g.Value] |> List.tail |> Some
| _ -> None
 
// Parse and expand a single range description.
// string -> int list
let parseRange r =
match r with
| Regexp @"^(-?\d+)-(-?\d+)$" [first; last] -> [int first..int last]
| Regexp @"^(-?\d+)$" [single] -> [int single]
| _ -> failwithf "illegal range format: %s" r
 
 
let expand (desc:string) =
desc.Split(',')
|> List.ofArray
|> List.collect parseRange
 
printfn "%A" (expand "-6,-3--1,3-5,7-11,14,15,17-20")
Output:
[-6; -3; -2; -1; 3; 4; 5; 7; 8; 9; 10; 11; 14; 15; 17; 18; 19; 20]

Go[edit]

A version rather strict with input

package main
 
import (
"fmt"
"strconv"
"strings"
)
 
const input = "-6,-3--1,3-5,7-11,14,15,17-20"
 
func main() {
fmt.Println("range:", input)
var r []int
var last int
for _, part := range strings.Split(input, ",") {
if i := strings.Index(part[1:], "-"); i == -1 {
n, err := strconv.Atoi(part)
if err != nil {
fmt.Println(err)
return
}
if len(r) > 0 {
if last == n {
fmt.Println("duplicate value:", n)
return
} else if last > n {
fmt.Println("values not ordered:", last, ">", n)
return
}
}
r = append(r, n)
last = n
} else {
n1, err := strconv.Atoi(part[:i+1])
if err != nil {
fmt.Println(err)
return
}
n2, err := strconv.Atoi(part[i+2:])
if err != nil {
fmt.Println(err)
return
}
if n2 < n1+2 {
fmt.Println("invalid range:", part)
return
}
if len(r) > 0 {
if last == n1 {
fmt.Println("duplicate value:", n1)
return
} else if last > n1 {
fmt.Println("values not ordered:", last, ">", n1)
return
}
}
for i = n1; i <= n2; i++ {
r = append(r, i)
}
last = n2
}
}
fmt.Println("expanded:", r)
}

Groovy[edit]

Ad Hoc Solution:

  1. translate the task's range syntax into Groovy range syntax
  2. wrap with list delimiters
  3. evaluate the script expression
  4. flatten the nested lists
  5. express as a string
  6. unwrap the list delimiters
def expandRanges = { compressed ->
Eval.me('['+compressed.replaceAll(~/(\d)-/, '$1..')+']').flatten().toString()[1..-2]
}

Test:

def s = '-6,-3--1,3-5,7-11,14,15,17-20'
println (expandRanges(s))
Output:
-6, -3, -2, -1, 3, 4, 5, 7, 8, 9, 10, 11, 14, 15, 17, 18, 19, 20

Haskell[edit]

Given either of the below implementations of expandRange:

> expandRange "-6,-3--1,3-5,7-11,14,15,17-20"
[-6,-3,-2,-1,3,4,5,7,8,9,10,11,14,15,17,18,19,20]

With conventional list processing[edit]

expandRange :: String -> [Int]
expandRange = concatMap f . split ','
where f str@(c : cs) | '-' `elem` cs = [read (c : a) .. read b]
| otherwise = [read str]
where (a, _ : b) = break (== '-') cs
 
split :: Eq a => a -> [a] -> [[a]]
split delim [] = []
split delim l = a : split delim (dropWhile (== delim) b)
where (a, b) = break (== delim) l

With a parser[edit]

import Control.Applicative (Applicative((<*>),(*>)),(<$>))
import Text.Parsec
 
expandRange :: String -> Maybe [Int]
expandRange = either (const Nothing) Just . parse rangeParser ""
 
rangeParser :: Parser [Int]
rangeParser = concat <$> (item `sepBy` char ',')
where item = do n1 <- num
n2 <- option n1 (char '-' *> num)
return [n1 .. n2]
num :: Parser Int
num = read `dot` (++) <$> option "" (string "-") <*> many1 digit
dot = ((.).(.))

Icon and Unicon[edit]

procedure main()
s := "-6,-3--1,3-5,7-11,14,15,17-20"
write("Input string  := ",s)
write("Expanded list  := ", list2string(range_expand(s)) | "FAILED")
end
 
procedure range_expand(s) #: return list of integers extracted from an ordered string representation
local R,low,high
R := []
 
s ? until pos(0) do {
put(R,low := integer(tab(upto(',-')|0))| fail) # get lower bound
if ="-" || (high := integer(tab(find(",")|0))|fail) then
until low = high do put(R,low +:= 1) # find range
=","
}
return R
end
 
procedure list2string(L) #: helper function to convert a list to a string
local s
 
every (s := "[ ") ||:= !L || " "
return s || "]"
end
Output:
Input string      := -6,-3--1,3-5,7-11,14,15,17-20
Expanded list   := [ -6 -3 -2 -1 3 4 5 7 8 9 10 11 14 15 17 18 19 20 ]

J[edit]

require'strings'
thru=: <. + i.@(+*)@-~
num=: _&".
normaliz=: rplc&(',-';',_';'--';'-_')@,~&','
subranges=:<@(thru/)@(num;._2)@,&'-';._1
rngexp=: ;@[email protected]
Example:
   rngexp '-6,-3--1,3-5,7-11,14,15,17-20'
_6 _3 _2 _1 3 4 5 7 8 9 10 11 14 15 17 18 19 20

Notes:

thru: given two integers (left: start of range, right: end of range) return the corresponding sequence of adjacent integers

num: given the string representation of a number, returns the number

normaliz: given the task required string representing a sequence of ranges, create a fresh copy with fewer micro ambiguities: All subranges are preceded by a comma. Negative numbers use a different character ('_') than the continuous range character ('-').

subranges: given the result of normaliz, return a sequence of boxes (one box for each comma). Each box contains the subrange which is described after its comma.

As an aside, note also that thru/ is an identity function when applied to a single number. This is because (verb/) inserts the verb between each number (or each item in a list), and this is an identity function on a single number, regardless of any definition of the verb. Fortunately, this is consistent with the definition of thru (and is also consistent for any combining verb which has an identity element). Note that this is very similar to the self-justifying fold definition (specifically a right fold, because of J's structure), but fold can be considerably harder to reason about because it explicitly avoids the concept of identity for combining functions. You should maybe consider using a loop in contexts where this is an issue.

Also note that current versions of J no longer need require'strings' as those routines are included by default. (But let's leave this in place because current versions of J still have some catching up to do in some areas, such as lab support.)

Java[edit]

import java.util.*;
 
class RangeExpander implements Iterator<Integer>, Iterable<Integer> {
 
private static final Pattern TOKEN_PATTERN = Pattern.compile("([+-]?\\d+)-([+-]?\\d+)");
 
private final Iterator<String> tokensIterator;
 
private boolean inRange;
private int upperRangeEndpoint;
private int nextRangeValue;
 
public RangeExpander(String range) {
String[] tokens = range.split("\\s*,\\s*");
this.tokensIterator = Arrays.asList(tokens).iterator();
}
 
@Override
public boolean hasNext() {
return hasNextRangeValue() || this.tokensIterator.hasNext();
}
 
private boolean hasNextRangeValue() {
return this.inRange && this.nextRangeValue <= this.upperRangeEndpoint;
}
 
@Override
public Integer next() {
if (!hasNext()) {
throw new NoSuchElementException();
}
 
if (hasNextRangeValue()) {
return this.nextRangeValue++;
}
 
String token = this.tokensIterator.next();
 
Matcher matcher = TOKEN_PATTERN.matcher(token);
if (matcher.find()) {
this.inRange = true;
this.upperRangeEndpoint = Integer.valueOf(matcher.group(2));
this.nextRangeValue = Integer.valueOf(matcher.group(1));
return this.nextRangeValue++;
}
 
this.inRange = false;
return Integer.valueOf(token);
}
 
@Override
public Iterator<Integer> iterator() {
return this;
}
 
}
 
class RangeExpanderTest {
public static void main(String[] args) {
RangeExpander re = new RangeExpander("-6,-3--1,3-5,7-11,14,15,17-20");
for (int i : re) {
System.out.print(i + " ");
}
}
}

JavaScript[edit]

Imperative (Spidermonkey)[edit]

#!/usr/bin/env js
 
function main() {
print(rangeExpand('-6,-3--1,3-5,7-11,14,15,17-20'));
}
 
function rangeExpand(rangeExpr) {
 
function getFactors(term) {
var matches = term.match(/(-?[0-9]+)-(-?[0-9]+)/);
if (!matches) return {first:Number(term)};
return {first:Number(matches[1]), last:Number(matches[2])};
}
 
function expandTerm(term) {
var factors = getFactors(term);
if (factors.length < 2) return [factors.first];
var range = [];
for (var n = factors.first; n <= factors.last; n++) {
range.push(n);
}
return range;
}
 
var result = [];
var terms = rangeExpr.split(/,/);
for (var t in terms) {
result = result.concat(expandTerm(terms[t]));
}
 
return result;
}
 
main();
 
Output:
-6,-3,-2,-1,3,4,5,7,8,9,10,11,14,15,17,18,19,20

Functional (ES 5)[edit]

(function (strTest) {
'use strict';
 
// s -> [n]
function expansion(strExpr) {
 
// concat map yields flattened output list
return [].concat.apply([], strExpr.split(',')
.map(function (x) {
return x.split('-')
.reduce(function (a, s, i, l) {
 
// negative (after item 0) if preceded by an empty string
// (i.e. a hyphen-split artefact, otherwise ignored)
return s.length ? i ? a.concat(
parseInt(l[i - 1].length ? s :
'-' + s, 10)
) : [+s] : a;
}, []);
 
// two-number lists are interpreted as ranges
})
.map(function (r) {
return r.length > 1 ? range.apply(null, r) : r;
}));
}
 
 
// [m..n]
function range(m, n) {
return Array.apply(null, Array(n - m + 1))
.map(function (x, i) {
return m + i;
});
}
 
return expansion(strTest);
 
})('-6,-3--1,3-5,7-11,14,15,17-20');
Output:
[-6, -3, -2, -1, 3, 4, 5, 7, 8, 9, 10, 11, 14, 15, 17, 18, 19, 20]

jq[edit]

Works with: jq version with regex support
def expand_range:
def number: "-?[0-9]+";
def expand: [range(.[0]; .[1] + 1)];
 
split(",")
| reduce .[] as $r
( []; . +
($r | if test("^\(number)$") then [tonumber]
else sub( "(?<x>\(number))-(?<y>\(number))"; "\(.x):\(.y)")
| split(":") | map(tonumber) | expand
end));

Example:

"-6,-3--1,3-5,7-11,14,15,17-20" | expand_range
Output:
$ jq -c -n -f Range_expansion.jq

[-6,-3,-2,-1,3,4,5,7,8,9,10,11,14,15,17,18,19,20]

Julia[edit]

slurp(s) = readcsv(IOBuffer(s))
 
conv(s)= colon(map(x->parse(Int,x),match(r"^(-?\d+)-(-?\d+)$", s).captures)...)
 
expand(s) = mapreduce(x -> isa(x,Number)? Int(x) : conv(x), vcat, slurp(s))
Output:
julia> show(expand("-6,-3--1,3-5,7-11,14,15,17-20"))
[-6,-3,-2,-1,3,4,5,7,8,9,10,11,14,15,17,18,19,20]

K[edit]

grp : {1_'(&x=*x)_ x:",",x}
pos : {:[3=l:#p:&"-"=x;0,[email protected];2=l;p;0=*p;,0;0,p]}
conv: 0${(x;1_ y)}/'{(pos x)_ x}'
expd: {,/@[x;&2=#:'x;{(*x)+!1+,/-':x}]}
rnge: [email protected] grp x}
Example:
  rnge "-6,-3--1,3-5,7-11,14,15,17-20"
-6 -3 -2 -1 3 4 5 7 8 9 10 11 14 15 17 18 19 20


Lasso[edit]

define range_expand(expression::string) => {
local(parts) = regexp(`^(-?\d+)-(-?\d+)$`)
 
return (
with elm in #expression->split(`,`)
let isRange = #parts->setInput(#elm)&matches
select #isRange
 ? (integer(#parts->matchString(1)) to integer(#parts->matchString(2)))->asString
| integer(#elm)->asString
)->join(', ')
}
 
range_expand(`-6,-3--1,3-5,7-11,14,15,17-20`)
Output:
-6, -3, -2, -1, 3, 4, 5, 7, 8, 9, 10, 11, 14, 15, 17, 18, 19, 20


Liberty BASIC[edit]

print ExpandRange$( "-6,-3--1,3-5,7-11,14,15,17-20")
end
 
function ExpandRange$( compressed$)
for i = 1 to ItemCount( compressed$, ",")
item$ = word$( compressed$, i, ",")
dash = instr( item$, "-", 2) 'dash that is not the first character, is a separator
if dash then
for k = val( left$( item$, dash - 1)) to val( mid$( item$, dash + 1))
ExpandRange$ = ExpandRange$ + str$( k) + ","
next k
else
ExpandRange$ = ExpandRange$ + item$ + ","
end if
next i
ExpandRange$ = left$( ExpandRange$, len( ExpandRange$) - 1)
end function
 
function ItemCount( list$, separator$)
while word$(list$, ItemCount + 1, separator$) <> ""
ItemCount = ItemCount + 1
wend
end function
Output:
-6,-3,-2,-1,3,4,5,7,8,9,10,11,14,15,17,18,19,20

LiveCode[edit]

function range beginning ending stepping
local tRange, tBegin, tEnd, tstep
if stepping is empty or stepping is 0 then
put 1 into tstep
else
put abs(stepping) into tstep
end if
 
if ending is empty or isNumber(ending) is not true then
put 0 into tEnd
else
put ending into tEnd
end if
 
if beginning is empty or isNumber(beginning) is not true then
put 0 into tBegin
else
put beginning into tBegin
end if
 
repeat with r = tBegin to tEnd step tstep
put space & r after tRange
end repeat
return word 1 to -1 of tRange
end range
 
function expandRange rangeExpr
put rangeExpr into tRange
split tRange by comma
repeat with n = 1 to the number of elements of tRange
if matchText(tRange[n],"^(\-*\d+)\-(\-*\d+)",beginning, ending) then
put range(beginning, ending, 1) & space after z
else
put tRange[n] & space after z
end if
end repeat
return z
end expandRange

Test

expandRange("-6,-3--1,3-5,7-11,14,15,17-20")
-6 -3 -2 -1 3 4 5 7 8 9 10 11 14 15 17 18 19 20

Lua[edit]

function range(i, j)
local t = {}
for n = i, j, i<j and 1 or -1 do
t[#t+1] = n
end
return t
end
 
function expand_ranges(rspec)
local ptn = "([-+]?%d+)%s?-%s?([-+]?%d+)"
local t = {}
 
for v in string.gmatch(rspec, '[^,]+') do
local s, e = v:match(ptn)
 
if s == nil then
t[#t+1] = tonumber(v)
else
for i, n in ipairs(range(tonumber(s), tonumber(e))) do
t[#t+1] = n
end
end
end
return t
end
 
local ranges = "-6,-3--1,3-5,7-11,14,15,17-20"
print(table.concat(expand_ranges(ranges), ', '))

Due to the way Lua's tonumber function works and the way the string pattern to parse ranges is written, whitespace is allowed around commas and the dash separating the range start and end (but not between the plus/minus sign and the number).

Output:
    -6, -3, -2, -1, 3, 4, 5, 7, 8, 9, 10, 11, 14, 15, 17, 18, 19, 20

Maple[edit]

 
ExpandRanges := proc( s :: string )
uses StringTools;
local DoOne := proc( input )
uses StringTools;
local lo, hi, pos;
if IsDigit( input ) or input[ 1 ] = "-"
and IsDigit( input[ 2 .. -1 ] ) then
parse( input )
else
pos := Search( "--", input );
if pos > 0 then
lo := input[ 1 .. pos - 1 ];
hi := input[ 1 + pos .. -1 ];
elif input[ 1 ] = "-" then
pos := FirstFromLeft( "-", input[ 2 .. -1 ] );
if pos = 0 then
lo := input;
hi := lo
else
lo := input[ 1 .. pos ];
hi := input[ 2 + pos .. -1 ];
end if;
else
pos := FirstFromLeft( "-", input );
if pos = 0 then
error "incorrect syntax"
end if;
lo := input[ 1 .. pos - 1 ];
hi := input[ 1 + pos .. -1 ];
end if;
lo := parse( lo );
hi := parse( hi );
seq( lo .. hi )
end if
end proc:
map( DoOne, map( Trim, Split( s, "," ) ) )
end proc:
 

Running this on the example input we get the following.

 
> rng := "-6,-3--1,3-5,7-11,14,15,17-20":
> ExpandRanges( rng );
[-6, -3, -2, -1, 3, 4, 5, 7, 8, 9, 10, 11, 14, 15, 17, 18, 19, 20]
 

Here is an additional example which my first attempt got wrong.

 
> rng := "-6,-3-1,3-5,7-11,14,15,17-20":
> ExpandRanges( rng );
[-6, -3, -2, -1, 0, 1, 3, 4, 5, 7, 8, 9, 10, 11, 14, 15, 17, 18, 19, 20]
 

Mathematica[edit]

rangeexpand[ rng_ ] := Module[ { step1 },
step1 = StringSplit[StringReplacePart[rng,"S",StringPosition[ rng,DigitCharacter~~"-"] /. {x_,y_} -> {y,y}],","];
[email protected][email protected]@StringReplace[step1,x__~~"S"~~y__->"Range["<>x<>","<>y<>"]"] ]
Example:
rangeexpand["-6,-3--1,3-5,7-11,14,15,17-20"]
{-6,-3,-2,-1,3,4,5,7,8,9,10,11,14,15,17,18,19,20}

MATLAB / Octave[edit]

function L=range_expansion(S)
% Range expansion
if nargin < 1;
S='[]';
end
 
if ~all(isdigit(S) | (S=='-') | (S==',') | isspace(S))
error 'invalid input';
end
ixr = find(isdigit(S(1:end-1)) & S(2:end) == '-')+1;
S(ixr)=':';
S=['[',S,']'];
L=eval(S);

Usage:

   range_expansion('-6,-3--1,3-5,7-11,14,15,17-20 ')
ans =
   -6   -3   -2   -1    3    4    5    7    8    9   10   11   14   15   17   18   19   20

MUMPS[edit]

RANGEXP(X) ;Integer range expansion
NEW Y,I,J,X1,H SET Y=""
FOR I=1:1:$LENGTH(X,",") DO
.S X1=$PIECE(X,",",I) FOR Q:$EXTRACT(X1)'=" " S X1=$EXTRACT(X1,2,$LENGTH(X1)) ;clean up leading spaces
.SET H=$FIND(X1,"-")-1
.IF H=1 SET H=$FIND(X1,"-",(H+1))-1 ;If the first value is negative ignore that "-"
.IF H<0 SET Y=$SELECT($LENGTH(Y)=0:Y_X1,1:Y_","_X1)
.IF '(H<0) FOR J=+$EXTRACT(X1,1,(H-1)):1:+$EXTRACT(X1,(H+1),$LENGTH(X1)) SET Y=$SELECT($LENGTH(Y)=0:J,1:Y_","_J)
KILL I,J,X1,H
QUIT Y
Example:
USER>SET U="-6,-3--1,3-5,7-11,14,15,17-20"

USER>WRITE $$RANGEXP^ROSETTA(U)
-6,-3,-2,-1,3,4,5,7,8,9,10,11,14,15,17,18,19,20

NetRexx[edit]

Translation of: Rexx Version 2

/*NetRexx program to expand a range of integers into a list. *************
* 09.08.2012 Walter Pachl derived from my Rexx version
* Changes: translate(old,' ',',') -> old.translate(' ',',')
* dashpos=pos('-',x,2) -> dashpos=x.pos('-',2)
* Do -> Loop
* Parse Var a x a -> Parse a x a
* Parse Var x ... -> Parse x ...
**********************************************************************/

 
parse arg old
if old = '' then
old='-6,-3--1,3-5,7-11,14,15,17-20' /*original list of nums/ranges */
 
Say 'old='old /*show old list of nums/ranges. */
a=old.translate(' ',',') /*translate commas to blanks */
new='' /*new list of numbers (so far). */
 
comma=''
Loop While a<>'' /* as long as there is input */
Parse a x a /* get one element */
dashpos=x.pos('-',2) /* find position of dash, if any */
If dashpos>0 Then Do /* element is low-high */
Parse x low =(dashpos) +1 high /* split the element */
Loop j=low To high /* output all numbers in range */
new=new||comma||j /* with separating commas */
comma=',' /* from now on use comma */
End
End
Else Do /* element is a number */
new=new||comma||x /* append (with comma) */
comma=',' /* from now on use comma */
End
End
Say 'new='new /*show the expanded list */
 
Output:
old=-6,-3--1,3-5,7-11,14,15,17-20
new=-6,-3,-2,-1,3,4,5,7,8,9,10,11,14,15,17,18,19,20   

Nim[edit]

import parseutils, re, strutils
 
proc expandRange(input: string): string =
var output: seq[string] = @[]
for range in input.split(','):
var sep = range.find('-', 1)
if sep > 0: # parse range
var first = -1
if range.substr(0, sep-1).parseInt(first) == 0:
break
var last = -1
if range.substr(sep+1).parseInt(last) == 0:
break
for i in first..last:
output.add($i)
else: # parse single number
var n = -1
if range.parseInt(n) > 0:
output.add($n)
else:
break
return output.join(",")
 
echo("-6,-3--1,3-5,7-11,14,15,17-20".expandRange)
Output:
-6,-3,-2,-1,3,4,5,7,8,9,10,11,14,15,17,18,19,20

Oberon-2[edit]

Oxford Oberon-2

 
MODULE LIVector;
IMPORT SYSTEM;
TYPE
LIPool = POINTER TO ARRAY OF LONGINT;
LIVector*= POINTER TO LIVectorDesc;
LIVectorDesc = RECORD
cap-: INTEGER;
len-: INTEGER;
LIPool: LIPool;
END;
 
PROCEDURE (v: LIVector) Init*(cap: INTEGER);
BEGIN
v.cap := cap;
v.len := 0;
NEW(v.LIPool,cap);
END Init;
 
PROCEDURE (v: LIVector) Add*(x: LONGINT);
VAR
newLIPool: LIPool;
BEGIN
IF v.len = LEN(v.LIPool^) THEN
(* run out of space *)
v.cap := v.cap + (v.cap DIV 2);
NEW(newLIPool,v.cap);
SYSTEM.MOVE(SYSTEM.ADR(v.LIPool^),SYSTEM.ADR(newLIPool^),v.cap * SIZE(LONGINT));
v.LIPool := newLIPool
END;
v.LIPool[v.len] := x;
INC(v.len)
END Add;
 
PROCEDURE (v: LIVector) At*(idx: INTEGER): LONGINT;
BEGIN
RETURN v.LIPool[idx];
END At;
END LIVector.
 
MODULE LIRange;
IMPORT Out, LIV := LIVector;
 
TYPE
Range* = POINTER TO RangeDesc;
RangeDesc = RECORD
l,r: POINTER TO ARRAY 1 OF LONGINT;
END;
 
PROCEDURE (r: Range) Init*();
BEGIN
r.l := NIL;
r.r := NIL;
END Init;
 
PROCEDURE (r: Range) IsEmpty*(): BOOLEAN;
BEGIN
RETURN (r.l = NIL) & (r.l = NIL);
END IsEmpty;
 
PROCEDURE (r: Range) SetLeft*(v: LONGINT);
BEGIN
IF r.l = NIL THEN NEW(r.l) END;
r.l[0] := v;
END SetLeft;
 
PROCEDURE (r: Range) SetRight*(v : LONGINT);
BEGIN
IF r.r = NIL THEN NEW(r.r) END;
r.r[0] := v;
END SetRight;
 
PROCEDURE (r: Range) LeftPart*(): BOOLEAN;
BEGIN
RETURN r.l # NIL;
END LeftPart;
 
PROCEDURE (r: Range) GetLeft(): LONGINT;
BEGIN
RETURN r.l[0];
END GetLeft;
 
PROCEDURE (r: Range) RightPart*(): BOOLEAN;
BEGIN
RETURN r.l # NIL;
END RightPart;
 
PROCEDURE (r: Range) GetRight*(): LONGINT;
BEGIN
RETURN r.r[0];
END GetRight;
 
PROCEDURE (r: Range) Show*();
BEGIN
Out.Char('(');
IF r.l # NIL THEN Out.LongInt(r.l[0],10) END;
Out.String(" - ");
IF r.r # NIL THEN Out.LongInt(r.r[0],10); END;
Out.Char(')');Out.Ln
END Show;
 
PROCEDURE (r: Range) Expand*(VAR liv: LIV.LIVector);
VAR
from, to : LONGINT;
BEGIN
IF r.l # NIL THEN from := r.l[0] ELSE from := 0 END;
IF r.r # NIL THEN to := r.r[0] ELSE to := from END;
WHILE (from <= to) DO
liv.Add(from);INC(from)
END
END Expand;
END LIRange.
 
MODULE Splitter;
TYPE
Splitter* = POINTER TO SplitterDesc;
SplitterDesc = RECORD
from: INTEGER;
c: CHAR;
s: POINTER TO ARRAY OF CHAR;
END;
 
PROCEDURE (s: Splitter) Init*;
BEGIN
s.c := ',';
s.from := 0;
s.s := NIL;
END Init;
 
PROCEDURE (s: Splitter) On*(str: ARRAY OF CHAR);
BEGIN
s.from := 0;
NEW(s.s,LEN(str));
COPY(str,s.s^)
END On;
 
PROCEDURE (s: Splitter) OnWithChar*(str: ARRAY OF CHAR;c: CHAR);
BEGIN
s.from := 0;
s.c := c;
NEW(s.s,LEN(str));
COPY(str,s.s^)
END OnWithChar;
 
PROCEDURE (s: Splitter) Next*(VAR str: ARRAY OF CHAR);
VAR
k : INTEGER;
BEGIN
k := 0;
IF (s.from < LEN(s.s^) - 1) & (s.s[s.from] = 0X) THEN str[0] := 0X END;
WHILE (k < LEN(str) - 1) & (s.from < LEN(s.s^) - 1) & (s.s[s.from] # s.c) DO
str[k] := s.s[s.from];
INC(k);INC(s.from)
END;
IF k < LEN(str) - 1 THEN str[k] := 0X ELSE str[LEN(str) - 1] := 0X END;
WHILE (s.from < LEN(s.s^) - 1) & (s.s[s.from] # s.c) DO INC(s.from) END;
INC(s.from)
END Next;
END Splitter.
 
MODULE ExpandRange;
IMPORT Out, LIV := LIVector, LIR := LIRange, S := Splitter;
 
PROCEDURE GetNumberFrom(s: ARRAY OF CHAR; VAR from: INTEGER; VAR done: BOOLEAN): LONGINT;
VAR
d,i: INTEGER;
num,sign: LONGINT;
BEGIN
i := from; num := 0;sign := 1;
CASE s[i] OF
'-': sign := -1;INC(i)
|'+': INC(i);
ELSE
END;
WHILE (i < LEN(s) - 1) & (s[i] >= '0') & (s[i] <= '9') DO
d := ORD(s[i]) - ORD('0');
num := d + num * 10;
INC(i);
END;
IF i = from THEN done := FALSE ELSE done := TRUE; from := i END;
RETURN sign * num
END GetNumberFrom;
 
PROCEDURE GetRange(s: ARRAY OF CHAR): LIR.Range;
VAR
r: LIR.Range;
i: INTEGER;
num: LONGINT;
done: BOOLEAN;
BEGIN
i := 0;NEW(r);r.Init();
WHILE (i < LEN(s) - 1) & (s[i] = 20X) DO INC(i) END;
(* Left value *)
done := FALSE;
num := GetNumberFrom(s,i,done);
IF ~done THEN RETURN r END;
r.SetLeft(num);
 
WHILE (i < LEN(s) - 1) & (s[i] = 20X) DO INC(i) END;
CASE s[i] OF
'-' : INC(i);
| 0X : RETURN r;
ELSE
END;
WHILE (i < LEN(s) - 1) & (s[i] = 20X) DO INC(i) END;
 
(* Right Value *)
done := FALSE;
num := GetNumberFrom(s,i,done);
IF ~done THEN RETURN r END;
r.SetRight(num);
RETURN r;
END GetRange;
 
VAR
i: INTEGER;
r: LIR.Range;
sp: S.Splitter;
p : ARRAY 128 OF CHAR;
liv: LIV.LIVector;
BEGIN
NEW(sp);sp.Init();
NEW(liv);liv.Init(128);
 
sp.On("-6,-3--1,3-5,7-11,14,15,17-20");
sp.Next(p);
WHILE (p[0] # 0X) DO
r := GetRange(p);
r.Expand(liv);
sp.Next(p);
END;
FOR i := 0 TO liv.len - 2 DO
Out.LongInt(liv.At(i),3);Out.Char(',');
END;
Out.LongInt(liv.At(liv.len - 1),3);Out.Ln;
END ExpandRange.
 
 
Output:
-6, -3, -2, -1,  3,  4,  5,  7,  8,  9, 10, 11, 14, 15, 17, 18, 19, 20

OCaml[edit]

#load "str.cma"
 
let range a b =
if b < a then invalid_arg "range";
let rec aux i acc =
if i = b then List.rev(i::acc)
else aux (succ i) (i::acc)
in
aux a []
 
let parse_piece s =
try Scanf.sscanf s "%d-%d" (fun a b -> range a b)
with _ -> [int_of_string s]
 
let range_expand rng =
let ps = Str.split (Str.regexp_string ",") rng in
List.flatten (List.map parse_piece ps)
 
let () =
let rng = "-6,-3--1,3-5,7-11,14,15,17-20" in
let exp = range_expand rng in
List.iter (Printf.printf " %d") exp;
print_newline()

ooRexx[edit]

 
list = '-6,-3--1,3-5,7-11,14,15,17-20'
expanded = expandRanges(list)
 
say "Original list: ["list"]"
say "Expanded list: ["expanded~tostring("l", ",")"]"
 
-- expand a string expression a range of numbers into a list
-- of values for the range. This returns an array
::routine expandRanges
use strict arg list
values = list~makearray(',')
-- build this up using an array first. Make this at least the
-- size of the original value set.
expanded = .array~new(values~items)
 
-- now process each element in the range
loop element over values
-- if this is a valid number, it's not a range, so add it directly
if element~datatype('whole') then expanded~append(element)
else do
-- search for the divider, starting from the second position
-- to allow for the starting value to be a minus sign.
split = element~pos('-', 2)
parse var element start =(split) +1 finish
loop i = start to finish
expanded~append(i)
end
end
end
return expanded
 
Output:
Original list: [-6,-3--1,3-5,7-11,14,15,17-20]
Expanded list: [-6,-3,-2,-1,3,4,5,7,8,9,10,11,14,15,17,18,19,20]

Oz[edit]

declare
fun {Expand RangeDesc}
{Flatten
{Map {ParseDesc RangeDesc}
ExpandRange}}
end
 
fun {ParseDesc Txt}
{Map {String.tokens Txt &,} ParseRange}
end
 
fun {ParseRange R}
if {Member &- R.2} then
First Second
in
{String.token R.2 &- ?First ?Second}
{String.toInt R.1|First}#{String.toInt Second}
else
Singleton = {String.toInt R}
in
Singleton#Singleton
end
end
 
fun {ExpandRange From#To}
{List.number From To 1}
end
in
{System.showInfo
{Value.toVirtualString {Expand "-6,-3--1,3-5,7-11,14,15,17-20"} 100 100}}
Sample output:
[~6 ~3 ~2 ~1 3 4 5 7 8 9 10 11 14 15 17 18 19 20]

Perl[edit]

One-liner:

sub rangex {
map { /^(.*\d)-(.+)$/ ? $1..$2 : $_ } split /,/, shift
}
 
# Test and display
print join(',', rangex('-6,-3--1,3-5,7-11,14,15,17-20')), "\n";
Output:
-6,-3,-2,-1,3,4,5,7,8,9,10,11,14,15,17,18,19,20

Alternative:

sub rangex {
(my $range = shift) =~ s/(?<=\d)-/../g;
eval $range;
}

Perl 6[edit]

Works with: Rakudo version 2016.07
sub range-expand (Str $range-description) {
my token number { '-'? \d+ }
my token range { (<&number>) '-' (<&number>) }
 
$range-description
.split(',')
.map({ .match(&range) ?? $0..$1 !! +$_ })
.flat
}
 
say range-expand('-6,-3--1,3-5,7-11,14,15,17-20').join(', ');
Output:
-6, -3, -2, -1, 3, 4, 5, 7, 8, 9, 10, 11, 14, 15, 17, 18, 19, 20


Alternatively, using a grammar:

grammar RangeList {
token TOP { <term>* % ',' { make $<term>.map(*.made) } }
token term { [<range>|<num>] { make ($<num> // $<range>).made } }
token range { <num> '-' <num> { make +$<num>[0] .. +$<num>[1] } }
token num { '-'? \d+ { make +$/ } }
}
 
say RangeList.parse('-6,-3--1,3-5,7-11,14,15,17-20').made.flat.join(', ');
Output:
-6, -3, -2, -1, 3, 4, 5, 7, 8, 9, 10, 11, 14, 15, 17, 18, 19, 20

PHP[edit]

Translation of: Python
function rangex($str) {
$lst = array();
foreach (explode(',', $str) as $e) {
if (strpos($e, '-', 1) !== FALSE) {
list($a, $b) = explode('-', substr($e, 1), 2);
$lst = array_merge($lst, range($e[0] . $a, $b));
} else {
$lst[] = (int) $e;
}
}
return $lst;
}

PicoLisp[edit]

(de rangeexpand (Str)
(make
(for S (split (chop Str) ",")
(if (index "-" (cdr S))
(chain
(range
(format (head @ S))
(format (tail (- -1 @) S)) ) )
(link (format S)) ) ) ) )
Output:
: (rangeexpand "-6,-3--1,3-5,7-11,14,15,17-20")
-> (-6 -3 -2 -1 3 4 5 7 8 9 10 11 14 15 17 18 19 20)

PL/I[edit]

range_expansion:
procedure options (main);
 
get_number:
procedure (Number, c, eof);
declare number fixed binary (31), c character (1), eof bit (1) aligned;
declare neg fixed binary (1);
 
number = 0; eof = false;
do until (c ^= ' ');
get edit (c) (a(1));
end;
if c = '-' then do; get edit (c) (a(1)); neg = -1; end; else neg = 1;
do forever;
select (c);
when ('0', '1', '2', '3', '4', '5', '6', '7', '8', '9')
number = number*10 + c;
when (',', '-') do; number = neg*number; return; end;
otherwise signal error;
end;
on endfile (sysin) go to exit;
get edit (c) (a(1));
end;
exit:
number = neg*number;
eof = true;
end get_Number;
 
declare c character, (i, range_start, range_end) fixed binary (31);
declare eof bit (1) aligned;
declare true bit (1) value ('1'b), false bit (1) value ('0'b);
declare delimiter character (1) initial (' ');
declare out file output;
 
open file (out) output title ('/out, type(text),recsize(80)');
do while (^eof);
call get_number(range_start, c, eof);
if c = '-' then /* we have a range */
do;
call get_number (range_end, c, eof);
do i = range_start to range_end;
put file (out) edit (delimiter, i) (a, f(3));
end;
end;
else
do;
put file (out) edit (delimiter, range_start) (a, f(3));
end;
delimiter = ',';
end;
end range_expansion;
Output:
  -6, -3, -2, -1,  3,  4,  5,  7,  8,  9, 10, 11, 14, 15, 17, 18, 19, 20

PowerShell[edit]

 
function range-expansion($array) {
function expansion($arr) {
if($arr) {
$arr = $arr.Split(',')
$arr | foreach{
$a = $_
$b, $c, $d, $e = $a.Split('-')
switch($a) {
$b {return $a}
"-$c" {return $a}
"$b-$c" {return "$(([Int]$b)..([Int]$c))"}
"-$c-$d" {return "$(([Int]$("-$c"))..([Int]$d))"}
"-$c--$e" {return "$(([Int]$("-$c"))..([Int]$("-$e")))"}
}
}
} else {""}
}
$OFS = ", "
"$(expansion $array)"
$OFS = " "
}
range-expansion "-6,-3--1,3-5,7-11,14,15,17-20"
 

Output:

-6, -3, -2, -1, 3, 4, 5, 7, 8, 9, 10, 11, 14, 15, 17, 18, 19, 20

Prolog[edit]

Works with: SWI Prolog
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 expansion and Range extraction work with the same predicates but in reverse order.

range_expand :-
L = '-6,-3--1,3-5,7-11,14,15,17-20',
writeln(L),
atom_chars(L, LA),
extract_Range(LA, R),
maplist(study_Range, R, LR),
pack_Range(LX, LR),
writeln(LX).
 
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% 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]).
Output:
 ?- range_expand.
-6,-3--1,3-5,7-11,14,15,17-20
[-6,-3,-2,-1,3,4,5,7,8,9,10,11,14,15,17,18,19,20]
true

PureBasic[edit]

Procedure rangeexpand(txt.s, List outputList())
Protected rangesCount = CountString(txt, ",") + 1
Protected subTxt.s, r, rangeMarker, rangeStart, rangeFinish, rangeIncrement, i
 
LastElement(outputList())
For r = 1 To rangesCount
subTxt = StringField(txt, r, ",")
rangeMarker = FindString(subTxt, "-", 2)
If rangeMarker
rangeStart = Val(Mid(subTxt, 1, rangeMarker - 1))
rangeFinish = Val(Mid(subTxt, rangeMarker + 1))
 
If rangeStart > rangeFinish
rangeIncrement = -1
Else
rangeIncrement = 1
EndIf
 
i = rangeStart - rangeIncrement
Repeat
i + rangeIncrement
AddElement(outputList()): outputList() = i
Until i = rangeFinish
Else
AddElement(outputList()): outputList() = Val(subTxt)
EndIf
Next
EndProcedure
 
Procedure outputListValues(List values())
Print("[ ")
ForEach values()
Print(Str(values()) + " ")
Next
PrintN("]")
EndProcedure
 
If OpenConsole()
NewList values()
rangeexpand("-6,-3--1,3-5,7-11,14,15,17-20", values())
outputListValues(values())
 
Print(#CRLF$ + #CRLF$ + "Press ENTER to exit")
Input()
CloseConsole()
EndIf
Output:
[ -6 -3 -2 -1 3 4 5 7 8 9 10 11 14 15 17 18 19 20 ]

Python[edit]

def rangeexpand(txt):
lst = []
for r in txt.split(','):
if '-' in r[1:]:
r0, r1 = r[1:].split('-', 1)
lst += range(int(r[0] + r0), int(r1) + 1)
else:
lst.append(int(r))
return lst
 
print(rangeexpand('-6,-3--1,3-5,7-11,14,15,17-20'))

Another variant, using regular expressions to parse the ranges:

import re
 
def rangeexpand(txt):
lst = []
for rng in txt.split(','):
start,end = re.match('^(-?\d+)(?:-(-?\d+))?$', rng).groups()
if end:
lst.extend(xrange(int(start),int(end)+1))
else:
lst.append(int(start))
return lst
Output:
[-6, -3, -2, -1, 3, 4, 5, 7, 8, 9, 10, 11, 14, 15, 17, 18, 19, 20]

another variant, using a functional style to parse the ranges:

from functools import reduce
from operator import add
 
def rangeexpand(s):
return reduce(add,
map(lambda x: list(range(*map(int, x.split('-')))) if '-' in x else [int(x)], s.split(',')))
 
Output:
[-6, -3, -2, -1, 3, 4, 5, 7, 8, 9, 10, 11, 14, 15, 17, 18, 19, 20]

R[edit]

 
rangeExpand <- function(text) {
lst <- gsub("(\\d)-", "\\1:", unlist(strsplit(text, ",")))
unlist(sapply(lst, function (x) eval(parse(text=x))), use.names=FALSE)
}
 
rangeExpand("-6,-3--1,3-5,7-11,14,15,17-20")
[1] -6 -3 -2 -1 3 4 5 7 8 9 10 11 14 15 17 18 19 20
 

Racket[edit]

 
#lang racket
 
(define (range-expand s)
(append*
(for/list ([r (regexp-split "," s)])
(match (regexp-match* "(-?[0-9]+)-(-?[0-9]+)" r
#:match-select cdr)
[(list (list f t))
(range (string->number f) (+ (string->number t) 1))]
[(list)
(list (string->number r))]))))
 
(range-expand "-6,-3--1,3-5,7-11,14,15,17-20")
 
Output:
'(-6 -3 -2 -1 3 4 5 7 8 9 10 11 14 15 17 18 19 20)

Here is an alternative version without regular expressions. It uses the builtin function read to read the numbers. Since 3--4 is normally parsed as a symbol rather than 3 followed by - followed by -4, a readtable is installed that makes - a delimiter.

 
#lang racket
 
(define on-minus
(case-lambda
[(ch ip) (on-minus ch ip #f #f #f #f)]
[(ch ip src line col pos)
(if (char-numeric? (peek-char ip))
(- (read ip))
(datum->syntax #f '-))]))
 
(define minus-delimits
(make-readtable (current-readtable) #\- 'terminating-macro on-minus))
 
(define (range-expand s)
(parameterize ([current-readtable minus-delimits])
(append*
(for/list ([f (in-port read s)])
(match (peek-char s)
[#\, (read-char s)
(list f)]
[#\- (read-char s)
(define t (read s))
(read-char s)
(range f (+ t 1))])))))
 
(range-expand (open-input-string "-6,-3--1,3-5,7-11,14,15,17-20"))
 

Note that one can use the full number syntax in this alternative version:

> (range-expand (open-input-string "1-6/3,3e1-32"))
'(1 2 30.0 31.0 32.0)

Raven[edit]

Based loosely on Ruby

define get_num use $lst
# "-22" split by "-" is [ "", "22" ] so check if
# first list item is "" -> a negative number
$lst 0 get "" = if
# negative number
#
# convert str to integer and multiply by -1
-1 $lst 1 get 0 prefer *
$lst shift $lst shift drop drop
else
# positive number
$lst 0 get 0 prefer
$lst shift drop
 
define range_expand use $rng
[ ] as $res
$rng "," split each as $r
$r m/^(-?\d+)-(-?\d+)$/ TRUE = if
$r s/-/g as $parts
$parts get_num as $from
$parts get_num as $to
# int list to str list, then joined by ","
group
$from $to 1 range each "" prefer
list "," join $res push
# range doesn't include the $to, so add to end of generated range
$to "%d" $res push
else
$r $res push
$res "," join print
"\n" print
 
'-6,-3--1,3-5,7-11,14,15,17-20' range_expand
Output:
-6,-3,-2,-1,3,4,5,7,8,9,10,11,14,15,17,18,19,20

REXX[edit]

version 1[edit]

Extra imbedded blanks were added to the   old   list (which are ignored) to make the   over/under   comparison easier   (in the output).

/*REXX program expands an  ordered list  of  integers  into  an expanded list.          */
old= '-6,-3--1, 3-5, 7-11, 14,15,17-20'; a=translate(old,,',')
new= /*translate [↑] commas (,) ───► blanks*/
do until a==''; parse var a X a /*obtain the next integer ──or── range.*/
p=pos('-', X, 2) /*find the location of a dash (maybe). */
if p==0 then new=new X /*append integer X to the new list.*/
else do j=left(X,p-1) to substr(X,p+1); new=new j
end /*j*/ /*append a single [↑] integer at a time*/
end /*until*/
/*stick a fork in it, we're all done. */
new=translate( strip(new), ',', " ") /*remove the first blank, add commas. */
say 'old list: ' old /*show the old list of numbers/ranges.*/
say 'new list: ' new /* " " new " " numbers. */

output

old list:  -6,-3--1,   3-5,  7-11,       14,15,17-20
new list:  -6,-3,-2,-1,3,4,5,7,8,9,10,11,14,15,17,18,19,20

Version 2 somewhat simplified !?![edit]

/*REXX program to expand a range of integers into a list. *************
* 09.08.2012 Walter Pachl
**********************************************************************/

 
parse arg old
if old = '' then -
old='-6,-3--1,3-5,7-11,14,15,17-20' /*original list of nums/ranges */
 
Say 'old='old /*show old list of nums/ranges. */
a=translate(old,,',') /*translate commas to blanks */
new='' /*new list of numbers (so far). */
 
comma=''
Do While a<>'' /* as long as there is input */
Parse var a x a /* get one element */
dashpos=pos('-',x,2) /* find position of dash, if any */
If dashpos>0 Then Do /* element is low-high */
Parse Var x low =(dashpos) +1 high /* split the element */
Do j=low To high /* output all numbers in range */
new=new||comma||j /* with separating commas */
comma=',' /* from now on use comma */
End
End
Else Do /* element is a number */
new=new||comma||x /* append (with comma) */
comma=',' /* from now on use comma */
End
End
Say 'new='new /*show the expanded list */
Output:
old=-6,-3--1,3-5,7-11,14,15,17-20
new=-6,-3,-2,-1,3,4,5,7,8,9,10,11,14,15,17,18,19,20   

Ruby[edit]

def range_expand(rng)
rng.split(',').flat_map do |part|
if part =~ /^(-?\d+)-(-?\d+)$/
($1.to_i .. $2.to_i).to_a
else
Integer(part)
end
end
end
 
p range_expand('-6,-3--1,3-5,7-11,14,15,17-20')
Output:
[-6, -3, -2, -1, 3, 4, 5, 7, 8, 9, 10, 11, 14, 15, 17, 18, 19, 20]

Run BASIC[edit]

PRINT rangeExpand$("-6,-3--1,3-5,7-11,14,15,17-20")
end
 
function rangeExpand$(range$)
[loop]
i = INSTR(range$, "-", i+1)
IF i THEN
j = i
WHILE MID$(range$,j-1,1) <> "," AND j <> 1
j = j - 1
wend
IF i > j then
IF MID$(range$,j,i-j) <> str$(i-j)+" " THEN
t$ = ""
FOR k = VAL(MID$(range$,j)) TO VAL(MID$(range$,i+1))-1
t$ = t$ + str$(k) + ","
NEXT k
range$ = LEFT$(range$,j-1) + t$ + MID$(range$,i+1)
i = j + LEN(t$) + 2
end if
end if
end if
if i <> 0 then goto [loop]
rangeExpand$ = range$
end function
Output:
-6,-3,-2,-1,3,4,5,7,8,9,10,11,14,15,17,18,19,20

Rust[edit]

Rust doesn't have regex in standard library yet.

use std::str::FromStr;
 
// Precondition: range doesn't contain multibyte UTF-8 characters
fn range_expand(range : &str) -> Vec<i32> {
range.split(',').flat_map(|item| {
match i32::from_str(item) {
Ok(n) => n..n+1,
_ => {
let dashpos=
match item.rfind("--") {
Some(p) => p,
None => item.rfind('-').unwrap(),
};
let rstart=i32::from_str(
unsafe{ item.slice_unchecked(0,dashpos)} ).unwrap();
let rend=i32::from_str(
unsafe{ item.slice_unchecked(dashpos+1,item.len()) } ).unwrap();
rstart..rend+1
},
}
}).collect()
}
 
fn main() {
println!("{:?}", range_expand("-6,-3--1,3-5,7-11,14,15,17-20"));
}
 
Output:
[-6, -3, -2, -1, 3, 4, 5, 7, 8, 9, 10, 11, 14, 15, 17, 18, 19, 20]

S-lang[edit]

variable r_expres = "-6,-3--1,3-5,7-11,14,15,17-20", s, r_expan = {}, dpos, i;
 
foreach s (strchop(r_expres, ',', 0))
{
 % S-Lang built-in RE's are fairly limited, and have a quirk:
 % grouping is done with \\( and \\), not ( and )
 % [PCRE and Oniguruma RE's are available via standard libraries]
if (string_match(s, "-?[0-9]+\\(-\\)-?[0-9]+", 1)) {
 
(dpos, ) = string_match_nth(1);
 
 % Create/loop-over a "range array": from num before - to num after it:
foreach i ( [integer(substr(s, 1, dpos)) : integer(substr(s, dpos+2, -1))] )
list_append(r_expan, string(i));
}
else
list_append(r_expan, s);
}
print(strjoin(list_to_array(r_expan), ", "));

Scala[edit]

def rangex(str: String): Seq[Int] =
str split "," flatMap { (s) =>
val r = """(-?\d+)(?:-(-?\d+))?""".r
val r(a,b) = s
if (b == null) Seq(a.toInt) else a.toInt to b.toInt
}
Output:
> println(rangex("-6,-3-1,3-5,7-11,14,15,17-20"))
ArraySeq(-6, -3, -2, -1, 0, 1, 3, 4, 5, 7, 8, 9, 10, 11, 14, 15, 17, 18, 19, 20)
> println(rangex("-6,-3--1,3-5,7-11,14,15,17-20"))
ArraySeq(-6, -3, -2, -1, 3, 4, 5, 7, 8, 9, 10, 11, 14, 15, 17, 18, 19, 20)

Scheme[edit]

(define split
(lambda (str char skip count)
(let ((len (string-length str)))
(let loop ((index skip)
(last-index 0)
(result '()))
(if (= index len)
(reverse (cons (substring str last-index) result))
(if (eq? char (string-ref str index))
(loop (if (= count (+ 2 (length result)))
len
(+ index 1))
(+ index 1)
(cons char (cons (substring str last-index index)
result)))
(loop (+ index 1)
last-index
result)))))))
 
(define range-expand
(lambda (str)
(for-each
(lambda (token)
(if (char? token)
(display token)
(let ((range (split token #\- 1 2)))
(if (null? (cdr range))
(display (car range))
(do ((count (string->number (list-ref range 0)) (+ 1 count))
(high (string->number (list-ref range 2))))
((= count high) (display high))
(display count)
(display ","))))))
(split str #\, 0 0))
(newline)))
Output:
(range-expand "-6,-3--1,3-5,7-11,14,15,17-20")
-6,-3,-2,-1,3,4,5,7,8,9,10,11,14,15,17,18,19,20

Seed7[edit]

The library scanstri.s7i defines the function getInteger to extract substrings with integer literals (optional sign followed by a sequence of digits) from a string. The integer literals are converted to the type integer with the parse operator.

$ include "seed7_05.s7i";
include "scanstri.s7i";
 
const func array integer: rangeExpansion (in var string: rangeStri) is func
result
var array integer: numbers is 0 times 0;
local
var integer: number is 0;
begin
while rangeStri <> "" do
number := integer parse getInteger(rangeStri);
numbers &:= number;
if startsWith(rangeStri, "-") then
rangeStri := rangeStri[2 ..];
for number range succ(number) to integer parse getInteger(rangeStri) do
numbers &:= number;
end for;
end if;
if startsWith(rangeStri, ",") then
rangeStri := rangeStri[2 ..];
elsif rangeStri <> "" then
raise RANGE_ERROR;
end if;
end while;
end func;
 
const proc: main is func
local
var integer: number is 0;
begin
for number range rangeExpansion("-6,-3--1,3-5,7-11,14,15,17-20") do
write(number <& " ");
end for;
writeln;
end func;
Output:
-6 -3 -2 -1 3 4 5 7 8 9 10 11 14 15 17 18 19 20 

Sidef[edit]

func rangex(str) {
str.split(',').map { |r|
var m = r.match(/^
(?(DEFINE) (?<int>[+-]?[0-9]+) )
(?<from>(?&int))-(?<to>(?&int))
$/x)
m ? do {var c = m.ncap; (Num(c{:from}) .. Num(c{:to}))...}
 : Num(r)
}
}
 
say rangex('-6,-3--1,3-5,7-11,14,15,17-20').join(',')
Output:
-6,-3,-2,-1,3,4,5,7,8,9,10,11,14,15,17,18,19,20

SNOBOL4[edit]

*       # Return range n1 .. n2        
define('range(n1,n2)') :(range_end)
range range = range n1 ','; n1 = lt(n1,n2) n1 + 1 :s(range)
range rtab(1) . range :(return)
range_end
 
define('rangex(range)d1,d2')
num = ('-' | '') span('0123456789') :(rangex_end)
rangex range num . d1 '-' num . d2 = range(d1,d2) :s(rangex)
rangex = range :(return)
rangex_end
 
* # Test and display
output = rangex('-6,-3--1,3-5,7-11,14,15,17-20')
end
Output:
-6,-3,-2,-1,3,4,5,7,8,9,10,11,14,15,17,18,19,20

Tcl[edit]

proc rangeExpand desc {
set result {}
foreach term [split $desc ","] {
set count [scan $term %d-%d from to]
if {$count == 1} {
lappend result $from
} elseif {$count == 2} {
for {set i $from} {$i <= $to} {incr i} {lappend result $i}
}
}
return $result
}
 
puts [rangeExpand "-6,-3--1,3-5,7-11,14,15,17-20"]
Output:
-6 -3 -2 -1 3 4 5 7 8 9 10 11 14 15 17 18 19 20

TUSCRIPT[edit]

$$ MODE TUSCRIPT
rangednrs="-6,-3--1,3-5,7-11,14,15,17-20"
expandnrs=SPLIT (rangednrs,":,:")
 
LOOP/CLEAR r=expandnrs
test=STRINGS (r,":><-><<>>/:")
sz_test=SIZE (test)
IF (sz_test==1) THEN
expandnrs=APPEND (expandnrs,r)
ELSE
r=SPLIT (r,"::<|->/::-:",beg,end)
expandnrs=APPEND (expandnrs,beg)
LOOP/CLEAR next=beg,end
next=next+1
expandnrs=APPEND (expandnrs,next)
IF (next==end) EXIT
ENDLOOP
ENDIF
ENDLOOP
expandnrs= JOIN (expandnrs,",")
 
PRINT expandnrs
Output:
-6,-3,-2,-1,3,4,5,7,8,9,10,11,14,15,17,18,19,20 

TXR[edit]

A solution with three main parts:

  • a parse-expression-grammar driven parser to decimate the input to a Lisp data structure;
  • some Lisp code to expand the list, sort it, and remove duplicates (recursion, hashing, sorting).
  • driver code which matches the input with the grammar, and produces output with the help of the Lisp code.

The grammar is:

num := [ + | - ] { digit } +

entry := num [ ws ] - [ ws ] num
      |  num

rangelist := entry [ ws ] , [ ws ] rangelist
          |  entry
          |  /* empty */

Code:

@(define num (n))@(local tok)@{tok /[+\-]?\d+/}@(bind n @(int-str tok))@(end)
@(define entry (e))@\
@(local n1 n2)@\
@(cases)@\
@(num n1)@/\s*-\s*/@(num n2)@\
@(bind e (n1 n2))@\
@(or)@\
@(num n1)@\
@(bind e n1)@\
@(end)@\
@(end)
@(define rangelist (list))@\
@(local first rest)@\
@(cases)@\
@(entry first)@/\s*,\s*/@(rangelist rest)@\
@(bind list @(cons first rest))@\
@(or)@\
@(entry first)@\
@(bind list (first))@\
@(or)@\
@(bind list nil)@\
@(end)@\
@(end)
@(do
(defun expand-helper (list)
(cond
((null list) nil)
((consp (first list))
(append (range (first (first list))
(second (first list)))
(rangeexpand (rest list))))
(t (cons (first list) (rangeexpand (rest list))))))
 
(defun rangeexpand (list)
(uniq (expand-helper list))))
@(repeat)
@(rangelist x)@{trailing-junk}
@(output)
raw syntax: @x
expansion: @(rangeexpand x)
your junk: @{trailing-junk}
@(end)
@(end)
Run:
$ txr range-expansion.txr -
1,2,3-5,-3--1
raw syntax: 1 2 (3 5) (-3 -1)
expansion:  (-3 -2 -1 1 2 3 4 5)
your junk:
-6,-3--1,3-5,7-11,14,15,17-20
raw syntax: -6 (-3 -1) (3 5) (7 11) 14 15 (17 20)
expansion:  (-6 -3 -2 -1 3 4 5 7 8 9 10 11 14 15 17 18 19 20)
your junk:
-6,-3--1,3-5,7-11,14,15,17-20,[email protected]
raw syntax: -6 (-3 -1) (3 5) (7 11) 14 15 (17 20)
expansion:  (-6 -3 -2 -1 3 4 5 7 8 9 10 11 14 15 17 18 19 20)
your junk:  [email protected]

Note how the junk in the last example does not contain the trailing comma. This is because the rangelist grammar production allows for an empty range, so syntax like "5," is valid: it's an entry followed by a comma and a rangelist, where the rangelist is empty.

UNIX Shell[edit]

Works with: bash
#!/usr/bin/bash
 
range_expand () (
IFS=,
set -- $1
n=$#
for element; do
if [[ $element =~ ^(-?[0-9]+)-(-?[0-9]+)$ ]]; then
set -- "$@" $(eval echo "{${BASH_REMATCH[1]}..${BASH_REMATCH[2]}}")
else
set -- "$@" $element
fi
done
shift $n
echo "$@"
# to return a comma-separated value: echo "${*// /,}"
)
 
range_expand "-6,-3--1,3-5,7-11,14,15,17-20"
Output:
-6 -3 -2 -1 3 4 5 7 8 9 10 11 14 15 17 18 19 20

Ursala[edit]

#import std
#import int
 
rex = sep`,; zrange+*= %zp~~htttPzztPQhQXbiNC+ rlc ~&r~=`-
 
#cast %zL
 
t = rex '-6,-3--1,3-5,7-11,14,15,17-20'
Output:
<-6,-3,-2,-1,3,4,5,7,8,9,10,11,14,15,17,18,19,20>

VBA[edit]

Public Function RangeExpand(AString as string)
' return a list with the numbers expressed in AString
Dim Splits() As String
Dim List() As Integer
Dim count As Integer
 
count = -1 'to start a zero-based List() array
' first split it using comma as delimiter
Splits = Split(AString, ",")
' process all fragments
For Each fragment In Splits
'is there a "-" in it (do not consider first character)?
P = InStr(2, fragment, "-")
If P > 0 Then 'yes, so it's a range: find start and end numbers
nstart = Val(left$(fragment, P - 1))
nend = Val(Mid$(fragment, P + 1))
j = count
count = count + (nend - nstart + 1)
'add numbers in range to List
ReDim Preserve List(count)
For i = nstart To nend
j = j + 1
List(j) = i
Next
Else
'not a range, add a single number
count = count + 1
ReDim Preserve List(count)
List(count) = Val(fragment)
End If
Next
RangeExpand = List
End Function
 
Public Sub RangeExpandTest()
'test function RangeExpand
Dim X As Variant
 
X = RangeExpand("-6,-3--1,3-5,7-11,14,15,17-20")
'print X
Debug.Print "Result:"
For Each el In X
Debug.Print el;
Next
Debug.Print
End Sub
Output:
RangeExpandTest
Result:
-6 -3 -2 -1  3  4  5  7  8  9  10  11  14  15  17  18  19  20 

XPL0[edit]

include c:\cxpl\codes;          \intrinsic 'code' declarations
string 0; \use zero-terminated strings, instead of MSb
char Str;
int Char, Inx;
 
 
proc GetCh; \Get character from Str
[Char:= Str(Inx);
Inx:= Inx+1;
]; \GetCh
 
 
func GetNum; \Get number from Str and return its value
int Neg, Num;
[Neg:= false;
if Char = ^- then [Neg:= true; GetCh];
Num:= 0;
while Char>=^0 & Char<=^9 do
[Num:= Num*10 + Char-^0;
GetCh;
];
return if Neg then -Num else Num;
]; \GetNum
 
 
int I, N0, N1;
[Str:= "-6,-3--1,3-5,7-11,14,15,17-20";
Inx:= 0;
GetCh; \one character look ahead
loop [N0:= GetNum;
IntOut(0,N0);
case Char of
^,: [GetCh; ChOut(0,^,)];
^-: [GetCh;
N1:= GetNum;
for I:= N0+1 to N1 do \expand range
[ChOut(0,^,); IntOut(0,I)];
if Char=^, then [GetCh; ChOut(0,^,)] else quit]
other quit; \must be 0 string terminator
];
CrLf(0);
]
Output:
-6,-3,-2,-1,3,4,5,7,8,9,10,11,14,15,17,18,19,20

zkl[edit]

fcn rangex(s){
fcn(s,re){
if (re.search(s)){
a,b:=re.matched[1,*].apply("toInt");
[a..b].walk();
}
else s;
} :
s.split(",").pump(List, _.fp1(RegExp(0'|(.*\d+)-(.*\d+)|)))
.flatten().concat(",");
}
ns="-6,-3-1,3-5,7-11,14,15,17-20";
rangex(ns).println();
 
ns="-6,-3--1,3-5,7-11,14,15,17-20";
rangex(ns).println();
Output:
-6,-3,-2,-1,0,1,3,4,5,7,8,9,10,11,14,15,17,18,19,20
-6,-3,-2,-1,3,4,5,7,8,9,10,11,14,15,17,18,19,20