In many Python When it comes to code , We may usually see __name__ This variable .
about Python This variable may not be very familiar to first-time users of .
It is good to understand in this way ,__name__ This variable is an identifier Python Global variables of the program .
We all know Python It's not main() Functional , If you are right about main Functions are not very familiar , You can make up your brain by yourself . Simply put, all programs need an entry when running ,main A function is the entry to a program , It is usually the entry after the program is started , All the programs are from main Function started .
__name__ Is a build to Python Variables in the interpreter , Used to identify the name of the currently running module .
This with Java Medium this.getClass().getName() It's kind of similar .
We can do some examples and tests below .
Suppose we have the following 2 File .
This file is imported as a module . The source code of the file is as follows ：
# -*- coding: utf-8 -*-
# PPython __name__ module ImportVarName
# Author - https://www.ossez.com
print("ImportVarName __name__ = %s" % __name__)
if __name__ == "__main__":
print("ImportVarName is being run directly")
else:
print("ImportVarName is being imported")This file can consider our main function file .
The source code of the file is as follows ：
# -*- coding: utf-8 -*-
# Python __name__ module Test
# Author - https://www.ossez.com
import ImportVarName
print("Main VarName __name__ = %s" % __name__)
if __name__ == "__main__":
print("VarName is being run directly")
else:
print("VarName is being imported")Some interpretations of the above running results are as follows .
If we run the source code directly ：VarName.py, We will get the following output .
ImportVarName __name__ = ImportVarName ImportVarName is being imported Main VarName __name__ = __main__ VarName is being run directly Process finished with exit code 0
We can see that it is because we run from what we think is the main function , But before the main function runs , We imported the module ImportVarName, So in the module ImportVarName Medium __name__ The variable will be defined as the name of the module you import .
If you run the imported module directly ImportVarName Words , modular ImportVarName Medium __name__ It will be displayed as __main__.
https://www.ossez.com/t/python-name/13393
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