Question

In C++ you can often drastically improve the readability of your code by careful usage of the ‘using’ keyword, for example:

void foo() {     std::vector< std::map <int, std::string> > crazyVector;     std::cout << crazyVector[0].begin()->first; } 

becomes

void foo() {     using namespace std; // limited in scope to foo     vector< map <int, string> > crazyVector;     cout << crazyVector[0].begin()->first; } 

Does something similar exist for python, or do I have to fully qualify everything?

I’ll add the disclaimer that I know that using has its pitfalls and it should be appropriately limited in scope.

Answer 1

As Bill said, Python does have the construction

from X import * 

but you can also explicitly specify which names you want imported from the module (namespace):

from X import foo, bar, blah 

This tends to make the code even more readable/easier to understand, since someone seeing an identifier in the source doesn’t need to hunt through all imported modules to see where it comes from. Here’s a related question: Namespace Specification In Absence of Ambuguity

EDIT: in response to Pax’s comment, I’ll mention that you can also write things like

import X.foo 

but then you’ll need to write

X.foo.moo() 

instead of just

foo.moo() 

This is not necessarily a bad thing, of course. I usually use a mixture of the from X import y and import X.y forms, whatever I feel makes my code clearest. It’s certainly a subjective thing to some extent.