Is this correct to import module only in function, not in a start of file?

Question

So, i have a itchy question about import ModuleName and where i should to put this operator. In a start of file or in a function?

import some_module

def main():
    some_module.SomeStuff()

Or:

def main():
    import some_module
    some_module.SomeStuff()

But if i'll use it in more than one function? Will this correct or stupid? Or i need to create class with __init__ function like this: self.module = some_module.SomeStuff()? And then call it in other functions under a class?

Answer 1

Creating a class for import is not pythonic actually it's bad. You should import module as a name space for calling functions in that module or you can import specific functions:

from some_module import SomeFunc1, SomeFunc2
# or
import some_module
some_module.SomeFunc1()

Import statement must be at top of the source file(look pep8)

Answer 2

• If you use some_module only in def main():, you could import it within the function.

• It does not improve the performance in most of the cases as statet in Should Python import statements always be at the top of a module?

• It also breaks the rules of PEP8

Answer 3

The correct way is import module or from module import func_a in the start of the file. It will look cleaner and better. If you only want to import one or two functions just use the second one.

Answer 4

pep08 recommands that all imports should happen at the beginning of the module, and that's the way to go unless you have a very compelling reason to do otherwise.

The only reason I can think of would be a circular dependency between two modules (module A tries to import module B which tries to import module A etc...), but then it's better to cleanly solve the problem by factoring the common elements in a third module that depends neither on A nor B.