I have written a python file a.py like this:
x = 1
def hello():
print x
hello()
When I do import a, it is printing the value of x
Till now my understanding is import will include the variables and function definitions but why it is executing the method hello()?
Python imports are not trivial, but in short, when a module gets imported, it is executed top to bottom. Since there is a call to hello, it will call the function and print hello.
For a deeper dive into imports, see:
To be able to use a file both standalone and as a module, you can check for __name__, which is set to __main__, when the program runs standalone:
if __name__ == '__main__':
hello()
See also: What does if __name__ == "__main__": do?
In Python, there is no clear separation between declaring and executing. In fact, there are only execution statements. For example, def hello():... is just a way to assign a function value to the module variable hello. All the statements in the module are executed in their order once the module is imported.
That's why they often use guards like:
if __name__=='__main__':
# call hello() only when the module is run as "python module.py"
hello()
You have called hello() function at the bottom, so when you do "import a" it will execute that function!
you need to remove the hello() at the end, that is what is executing the function. You only want the declarations in your file a.py
