Hi Jürgen, it looks like there is some inconsistency.
x←4 4⍴'XX' '' '' '' '' '' '' '' s←(⍳4)∘.,⍳4 s 1 1 1 2 1 3 1 4 2 1 2 2 2 3 2 4 3 1 3 2 3 3 3 4 4 1 4 2 4 3 4 4 ((∊2=⍴¨x)/,s)⌷x XX XX ----- expected (no leading empty elements) XX XX ⍴((∊2=⍴¨x)/,s)⌷x 2 2 ----- expected 2 1 (only one column) ⍴¨((∊2=⍴¨x)/,s)⌷x 0 2 0 2 ----- expected (no leading empty elements) 2 2 ------------------------------------- x←2 2⍴'XX' '' '' '' s←(⍳2)∘.,⍳2 ((∊2=⍴¨x)/,s)⌷x RANK ERROR ((∈2=⍴¨x)/,s)⌷x ^ ^ ------ expected (no RANK ERROR, equivalent result as in previous 4x4 matrix) XX Best Regards Hans-Peter
