Hi Jay, My intend was to get each matrix element defined by a (row,column)-pair like:
1 3 5∘.,1 3 5 ⍝ the row,column pairs in a matrix 1 1 1 3 1 5 3 1 3 3 3 5 5 1 5 3 5 5 (1 3 5∘.,1 3 5)⌷¨⊂A ⍝ the matrix elements (in a matrix) ACE KMO UWY (1 3 ∘.,1 3 )⌷¨⊂A ⍝ works nicely too - just two elements per vector AC KM (1 3) (1 3) ⌷¨⊂A ⍝ This works too, having just a vector of vectors - no matrix CC (1 3) (1 5) ⌷¨⊂A ⍝ Again - works - different elements from one row but .. CE (1 3) (5 1) ⌷¨⊂A ⍝ .. but the elements should be from different rows CU (2 1⍴(1 3) (5 1)) ⌷¨⊂A ⍝ And even better, getting the elements in row order too - this was, what I intended. C U (1 3) (5 1) ⌷A ⍝ However I got this - not realizing straight away I was on an other indexing trip:-) EA OK Can you imagine what happens at 24:00 hours when you get a matrix instead of a vector not including the elements (CU) you are looking for?? Best Regards Hans-Peter Am 06.11.18 um 15:42 schrieb Jay Foad: > ⎕←t←5 5⍴⎕A > ABCDE > FGHIJ > KLMNO > PQRST > UVWXY > (1 3 5)(1 3 5)⌷t > ACE > KMO > UWY > t[1 3 5;1 3 5]≡(1 3 5)(1 3 5)⌷t > 1 > > Perhaps you wanted to use something like Dyalog's choose indexing? > > x[(∊2=⍴¨x)/,s] > ┌──┬──┐ > │XX│XX│ > └──┴──┘ > > Jay.
