Only the Last One — hard Python for AI problem | Incognition

Only the Last One

10 pts · 10 coins

Python for AIHard

Only the Last One

.replace(old, new, 1) swaps the first match. A file-renaming tool needs to swap only the last one, for example to change the final - in a date.

Task: write replace_last(text, old, new) that returns text with only the last match of old replaced by new.

If old doesn't appear, return text unchanged.
old is never empty.
"Last" means the match that starts furthest to the right. In "aaa", the last "aa" starts at position 1.

Examples

text = "one, two, one"

old = "one"

new = "three"

returns 'one, two, three'

text = "a.b.c"

old = "."

new = "-"

returns 'a.b-c'

Hints

solution.py

1def replace_last(text, old, new):
2    # your code here
3    pass
4