import inside or outside function

Question

Possible Duplicate:
Should Python import statements always be at the top of a module?

In a very simple one-file python program like

# ------------------------

# place 1
# import something

def foo():

   # place 2
   # import something
   return something.foo()

def bar(f):
    ...

def baz():
    f = foo()
    bar(f)

baz()

# ----------------

Would you put the "import something" at place 1 or 2?

score 12 · Answer 1 · answered Aug 24 '11 at 08:37

PEP 8 specifies that:

Imports are always put at the top of the file, just after any module comments and docstrings, and before module globals and constants.

Imports should be grouped in the following order:
1. standard library imports
2. related third party imports
3. local application/library specific imports
  
  You should put a blank line between each group of imports.
  
  Put any relevant all specification after the imports.

score 5 · Answer 2 · answered Aug 24 '11 at 08:41

I'd principally agree with Robert S. answer, but sometimes it makes sense to put it into a function. Especially if you want to control the importing mechanism. This is useful if you cannot be sure if you actually have access to a specific module. Consider this example:

def foo():
    try:
        import somespecialmodule
        # do something
        # ...
    except ImportError:
        import anothermodule
        # do something else
        # ...

This might even be the case for standard library modules (I especially have in mind the optparse and argparse modules).

If you do that, it might be a good idea to mention it in a comment at the regular imports, so that whoever's reading the code gets a heads up. — Cassandra S., Aug 24 '11 at 11:52

import inside or outside function

2 Answers2