when to use import statements in the header, when to use import statements in the blocks where they are used?
Dave Angel
d at davea.name
Tue Feb 7 21:05:15 EST 2012
On 02/07/2012 08:48 PM, Lei Cheng wrote:
> Hi all,
>
> In a py file, when to use import statements in the header, when to use
> import statements in the blocks where they are used?
> What are the best practices?
> Thanks!
>
> Pat
>
Best practice is to put all the imports at the beginning of the module,
so they are easy to spot.
If you put an import inside a function, it gets re-executed each time
the function is called, which is a waste of time. Not too much, since
import first checks sys.modules to see if it's already loaded.
Also, avoid the from xxx import * form, as it pollutes the
namespace. And it makes it hard to figure out where a particular name
is declared.
I believe these and other best practices can be found in pep8.
http://www.python.org/dev/peps/pep-0008/
--
DaveA
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