ITT The J programming language

Examples of J: http://www.jsoftware.com/jwiki/Studio
A good introduction: http://www.jsoftware.com/help/primer/contents.htm
J for C programmers: http://www.jsoftware.com/help/jforc/contents.htm
Learning J: http://www.jsoftware.com/help/learning/contents.htm


quicksort=: (($:@(<#[) , (=#[) , $:@(>#[)) ({~ ?@#)) ^: (1<#)

[bold]   ] p=: ?.~ 23
4 22 16 15 18 14 7 8 0 21 3 13 20 9 11 19 6 17 2 5 1 10 12
   C. p
┌──┬─────────────────┬──────────────────────────┬──────────┐
│17│18 2 16 6 7 8 0 4│21 10 3 15 19 5 14 11 13 9│22 12 20 1│
└──┴─────────────────┴──────────────────────────┴──────────┘
   #&> C. p
1 8 10 4
   *./ #&> C. p
40
   # ~. {/\ (100,#p)$p
40
   p&{^:40 i.#p
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22
[/bold]