Function Definition and Call in Python

Question

When you call a function you must define it first, otherwise you will get an error message. But when you call a functions by another function it's okay to define a fuction after that, for example:

def repeat_name():
    print_name()
    print_name()

def print_name():
    print('Mahmud')

repeat_name()

In this example we call print_name function in repeat_name function before its defination, and it works fine, but why does this happen?

Note: I'm a beginner in Python.

CasualDemon · Accepted Answer · 2016-02-16 18:45:21Z

1

Think of it being interpreted as it is run, so the items inside the repeat_name function are not checked until the first time it is called at repeat_name() after the print_name function.

If you put the call to repeat_name() above the print_name function it would also fail.

That is why if you have the code:

def my_func(x):
    print(x)

my_func("hello world")

It doesn't freak out that it doesn't know what x is, becasue x will be defined when you first call that function my_func("hello world")

answered Feb 16, 2016 at 18:45

CasualDemon

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1 Comment

Mahmood Muhammad Nageeb Over a year ago

Thank you! I understand now. Functions' definitions have no effect on the execution, so when I call repeat_name function I actually call print_name function twice, is that right?

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