For better understanding here is a example code.
num = 0
def func(num):
num += 1
func(num)
print(num)
This code prints 0 but I want 1(incremented by func()), how can I do that?
How can I do that? Is it possible?
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Eric Whale
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Does this answer your question? [How do I pass a variable by reference?](https://stackoverflow.com/questions/986006/how-do-i-pass-a-variable-by-reference) – Carcigenicate Nov 01 '20 at 16:54
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I deliberately posted this question, because I couldn't find it somehow when I needed it. So I posted this with different title and link. Hope this helps – Eric Whale Nov 01 '20 at 16:57
2 Answers
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Long story short, you can't just put number in function and expect it to be passed by reference.
In python...
- (act like) pass by value : whole numbers, strings or tuples
- (act like) pass by reference : python list
You should visit here for more info about "Pass(call) by Object Reference".
https://www.geeksforgeeks.org/is-python-call-by-reference-or-call-by-value/
Eric Whale
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I know there is similar question and answer in here(stack overflow), but I couldn't find when I needed it. So I post similar question and answer with different title and link for more info. Hope this helps. – Eric Whale Nov 01 '20 at 16:54
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In python, when you declare a variable inside a function, python treats it as a new variable. That means, any changes to that variable doesnt show up Globally.
To go through his, add global to the top.
Example:
num = 0
def func():
global num
num += 1
func()
print(num)
Output:
1
AwesomeSam
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That is not true, python gets function parameter as "pass by object reference". Please check my answer on top. – Eric Whale Nov 03 '20 at 05:20
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