Python - Modify an input variable inside a function

Question

The following code:

def function(X):
    X.upper()
    if X == 'YES':
        print ('success')
    else:
        print ('fail')
function('yes')

Produces:

fail

But this code:

def function2(X):
    Y = X.upper()
    if Y == 'YES':
        print ('success')
    else:
        print ('fail')
function2('yes')

Gives me:

success

Why is this? I want to be able to edit my input variables within my functions. Is there a more efficient way to do this than copying variable values to new variables? I'm running Python 3.7.1.

Thanks!

score 3 · Answer 1 · answered Mar 04 '19 at 22:24

3

Because "".upper() returns new string, it doesn't change the original. Strings are immutable in Python.

answered Mar 04 '19 at 22:24

marke

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Python - Modify an input variable inside a function

1 Answers1