Why is string.replace in Python not working?

Question

I have the following python string:

game="""+-------+-------+-------+
|       |       |       |
|   1   |   2   |   3   |
|       |       |       |
+-------+-------+-------+
|       |       |       |
|   4   |   5   |   6   |
|       |       |       |
+-------+-------+-------+
|       |       |       |
|   7   |   8   |   9   |
|       |       |       |
+-------+-------+-------+
"""

This is considered a str still and I used the following to replace "5" with "X":

game.replace("5","X")

Then I print the output and still get:

+-------+-------+-------+
|       |       |       |
|   1   |   2   |   3   |
|       |       |       |
+-------+-------+-------+
|       |       |       |
|   4   |   5   |   6   |
|       |       |       |
+-------+-------+-------+
|       |       |       |
|   7   |   8   |   9   |
|       |       |       |
+-------+-------+-------+

Python strings are immutable, `.replace` returns a *new* string. — Jared Smith, Dec 08 '22 at 21:41
`.replace` is not an in-place operation. use `game = game.replace('5','X')` — Mark Tolonen, Dec 08 '22 at 21:41

CherylLamb · Answer 1 · 2022-12-08T21:43:13.987

2

What you are probably doing is

game="sample string 5"
game.replace("5", "X")

This wont work because python strings are immutable and .replace() doesn't modify the original string, it returns a new one

To fix:

game = game.replace("5, "X")

A little word about what it means for Strings to be immutable in python - it simply means that they cannot change during the runtime of the program.

edited Dec 08 '22 at 21:43

answered Dec 08 '22 at 21:41

CherylLamb

21
2

correct I forgot about this. – user19926715 Dec 08 '22 at 21:42

score 1 · Accepted Answer · answered Dec 08 '22 at 21:40

1

I think you are printing the wrong string. You need to print game.replace('5','X') directly or use an intermediate variable.

answered Dec 08 '22 at 21:40

samuelnehool

147
15

Ah thank you you reminded me of something ill update this – user19926715 Dec 08 '22 at 21:42

Why is string.replace in Python not working?

2 Answers2