Add commas to existing String

1

I need to take a string “S” and insert a comma every 3 characters

so convert this
ABCDEFGHIJ
to this
A,BCD,EFG,HIJ

note the groups of 3 count from the RIGHT

2

AI sez:

image
image695×372 34.2 KB

3

For Swift it suggests:

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image704×1457 96.3 KB

4 
let reversedString = String(s.reversed())
var result = ""
var counter = 0
for char in reversedString {
    if counter > 0 && counter % 3 == 0 { result.append(",")}
    result.append(char)
    counter += 1
 }
 s=String(result.reversed())
1 Like
5

Your AI code is much better than the ones I generated.

Maybe you could update it so it loop 3 chars at at time so it loops 1/3 less times?

1 Like
6

I thought you were inserting commas not colons ?

7

I am, but I had not yet created the “,” glyph used by the app, so the “:” was for testing :slight_smile:

8

For 8th I would probably write something like:

: 3split-from-right \ s -- s
  s:len 3 n:/mod !if
    drop  
  else
    s:/ -1 ( [3] s:/ "," a:join ) a:op! "," a:join
  then ;
1 Like
9

Where’s APL when we need it most?

10

I’d write it but since APL is a write only language not sure that’d be useful to anyone reading it

11

Would this be a moderate improvement by eliminating the need to check if counter > 0 each time:

let reversedString = String(s.reversed())
var result = “”
var counter = 1
for char in reversedString {
result.append(char)
if counter % 3 == 0 { result.append(“,”)}
counter += 1
}
s=String(result.reversed())