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Python Writing to Files

Posted by hamdi ismail
hamdi ismail
Courses Plus Student 8,927 Points

if __name__ == '__main__':

why we are using it when we can just call the function normally

1 Answer

Christopher Shaw
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Christopher Shaw
Python Web Development Techdegree Graduate 58,248 Points

The code here is executed when the file is 'run' from the command line. for example if we had a file called hello.py with the following contents. When you run python hello.py from the command line, it will excute main_function(). However if you import hello.py, it will not run. 

def main_function():
    print("Hello World")

if __name__ == '__main__': 
    main_function()
Chris Howell
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.a{fill-rule:evenodd;}techdegree seal-36
Chris Howell
Python Web Development Techdegree Graduate 49,703 Points
Chris Howell
.a{fill-rule:evenodd;}techdegree seal-36
Chris Howell
Python Web Development Techdegree Graduate 49,703 Points

To add onto this answer. Lets pretend we have a two files called import_me.py and test_me.py that looks like this.

import_me.py

def print_hello():
    print("Hello")

print("this is import_me.py")
print_hello()

Now from another file called, lets say test_me.py

test_me.py

import import_me

print("This is the test_me.py Script")

I would tell Python to run the test_me.py script

python test_me.py

You would get this output.

Output

this is the import_me.py
Hello
This is the test_me.py Script