time "z ← downcase ¨ words readfile 'big.txt'" 7.859168565
time "s ← sortvs z" 4.423386895 ⍝ well, read took 8 seconds (over a million words) ⍝ sorting the result took 5 seconds time "U ← ∪ z" 101.1162267 ⍝ why does the "∪" operator took so long ? eg: 101 seconds. pretty sure this can be improved by a factor 2 to 5 times shorter. my definitions: downcase←{ ⎕UCS (32×(⍵≥65)∧⍵≤90)+⍵←⎕UCS ⍵} readfile←{⎕fio[26] ⍵} sortvs←{⍵[⎕av⍋⊃⍵]} words←{(⍵ ∊ ,⎕ucs (65 97)∘.+⎕io-⍨⍳26) ⊂ ⍵} big.txt is the one used in several reports last 2 weeks. Xtian.