> Write a function that takes a character vector representing a DNA string and returns 4 integers of the number of occurrences for each of the symbols ‘A’, ‘C’, ‘G’, and ‘T’ respectively.
Wouldn't it be nice if Key had been a dyadic operator, taking as additional operand the "vocabulary"? ≢⍤⊢⌸'ACGT' would have done the trick.
With the current definition of Key, we'd have to amend the data: {¯1+⊢⍤≢⌸'ACGT',⍵}
Hm, now I wonder if Key could be overloaded to take an array operand which is the vocabulary, and then it'd return the groups, with the function defaulting to ⊢. Then the solution would be (≢⍤¯1)'ACGT'⌸
No, wait, it should be ⊂⍤⊢ instead of ⊢ and our solution would be ≢¨'ACGT⌸
Anyway, this is easy enough without Key: {'ACGT'∘.=⍵} gives us the four masks, and {+/'ACGT'∘.=⍵} gives us the counts.
I would like to use my old APL*PLUS PC functions on Dyalog or GNU APL. Is there a way to convert workspaces (preferred) or functions without having to retype the functions?
I have tried reformatting the functions as a character matrix in APLPLUS PC (control A in the edit window) and saving in a ....
