Python strip() not working inside a function

Question

I am trying to use strip() to trim off the space before and after a string. It works fine for

str1 = "  abdced "
str1.strip()

However when I use it inside a function, it is not working:

def func(str1):
    return str1.strip() 

print func("   abdwe ")

It won't trim off any space. Anyone can tell what's happening? Thanks!

`def func(str1): return str1.strip()` `assert func(" abcd ") == "abcd"` - not reproducible. — Łukasz Rogalski, Apr 21 '15 at 21:30
Basic rule of Python strings - you can't alter them, you can only create new ones (they are *immutable*) — cdarke, Apr 21 '15 at 21:39

score 8 · Answer 1 · answered Apr 21 '15 at 21:31

8

strip is not an in-place method, meaning it returns a value which must be reassigned like so:

str1 = str1.strip() # the string is reassigned to the returned stripped string

answered Apr 21 '15 at 21:31

Malik Brahimi

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The function does return the new value, so IMHO this isn't the explanation of the question. – Massimo Sep 17 '19 at 11:08

score 2 · Answer 2 · answered Apr 22 '15 at 00:28

Three things I see.

First, you are not assigning the strip variable to anything, second you are trying to do this in a return.

The return should only have the variables you wish to return to be used in another function. You can print from this function, but your return statement should not have any activity, only the variable to be returned.

Third, that print statement looks off to me. At the very least it isn't how I would do the print.

def func(str1):
    str1 = "  abdced "

    str2 = str1.strip()

    print(str2)

    return str1, str2

Python strip() not working inside a function

2 Answers2

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