Range expansion

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
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.

C.f. Range extraction

ALGOL 68

This example is incorrect. Please fix the code and remove this message.

Details: The task example was modified after discussion in the talk page.

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

Works with: ELLA ALGOL 68 version Any (with appropriate job cards) - tested with release 1.8-8d

<lang algol68>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 #
1. (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))

)</lang> Output:

         -6         -3         -2         -1         +0         +1         +3         +4         +5         +7         +8         +9        +10        +11        +14        +15        +17        +18        +19        +20

J

This example is incorrect. Please fix the code and remove this message.

Details: The task example was modified after discussion in the talk page.

<lang j>require'strings' to=: (+ i.)/@:(0 1 + -~/\) num=: _&". normaliz=: rplc&(',-';',_';'--';'-_')@,~&',' lumps=:<@(num`([:to num;._1@,~&'-')@.('-'&e.));._1 rngexp=: ;@lumps@normaliz</lang>

Example: <lang j> rngexp '-6,-3-1,3-5,7-11,14,15,17-20' _6 _3 _2 _1 0 1 3 4 5 7 8 9 10 11 14 15 17 18 19 20

  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</lang>

MUMPS

This example is incorrect. Please fix the code and remove this message.

Details: The task example was modified after discussion in the talk page.

<lang MUMPS> 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</lang>

Example:

USER>SET T="-6, -3, -2, -1, 0, 1, 3, 4, 5, 7, 8, 9, 10, 11, 14, 15, 17, 18, 19, 20 "

USER>WRITE $$RANGEXP^ROSETTA(T)
-6,-3,-2,-1,0,1,3,4,5,7,8,9,10,11,14,15,17,18,19,20
USER>SET U="-10--8,"_T WRITE U
-10--8,-6, -3, -2, -1, 0, 1, 3, 4, 5, 7, 8, 9, 10, 11, 14, 15, 17, 18, 19, 20
USER>WRITE $$RANGEXP^ROSETTA(U)
-10,-9,-8,-6,-3,-2,-1,0,1,3,4,5,7,8,9,10,11,14,15,17,18,19,20

OCaml

This example is incorrect. Please fix the code and remove this message.

Details: The task example was modified after discussion in the talk page.

<lang ocaml>#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()</lang>

Oz

This example is incorrect. Please fix the code and remove this message.

Details: The task example was modified after discussion in the talk page.

<lang oz>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

 {Inspect {Expand "-6,-3-1,3-5,7-11,14,15,17-20"}}</lang>

Python

<lang python>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'))</lang>

Another variant, using regular expressions to parse the ranges:

<lang python>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</lang>

Sample output

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

Ruby

This example is incorrect. Please fix the code and remove this message.

Details: The task example was modified after discussion in the talk page.

<lang ruby>def range_expand(rng)

 lst = rng.split(',').collect do |part|
   begin
     Integer(part)
   rescue ArgumentError
     if part.scan(/^(-?\d+)-(-?\d+)$/)
       ($1.to_i .. $2.to_i).to_a
     else
       raise ArgumentError, "Can't parse part of range: '#{part}'"
     end
   end
 end
 lst.flatten

end

p range_expand('-6,-3-1,3-5,7-11,14,15,17-20')</lang>

output:

[-6, -3, -2, -1, 0, 1, 3, 4, 5, 7, 8, 9, 10, 11, 14, 15, 17, 18, 19, 20]

Tcl

This example is incorrect. Please fix the code and remove this message.

Details: The task example was modified after discussion in the talk page.

<lang tcl>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"]</lang> Output:

-6 -3 -2 -1 0 1 3 4 5 7 8 9 10 11 14 15 17 18 19 20