CODEWITHSUNDEEP
pythonimportpython-import
romeovs
romeovs

Reputation: 5953

Rename named parameter in Python to avoid naming conflicts with import statement

Say I have a function foo in a big Python project that has a named argument bar:

def foo(bar=42):
  do_something_with_bar(bar)

This function is called a lot in the codebase, in calls that use or omit the named bar parameter.

Now say I'm changing this function because it has a bug and want start using a function from a certain package, that is coincidentally also called bar. I cannot use the bar function when I import it like this:

from package import bar

def foo(bar=42):
  # how can I use the package.bar function here?
  do_something_with_bar(bar)

I could use something like:

from package import bar as package_bar

But this file also contains a lot of invocations of bar so that's a no-go.

The only way I can see this working is to rename the bar method from package:

from package import bar
package_bar = bar

def foo(bar=42):
  do_something_with_bar(package_bar(bar))

Or to import it multiple times (untested):

from package import bar, bar as package_bar

def foo(bar=42):
  do_something_with_bar(package_bar(bar))

Is there some way I can rename the bar parameter in the foo function, without all calls to the foo function breaking in the entire codebase?

Upvotes: 7

Views: 3251

Answers (5)

Sraw
Sraw

Reputation: 20224

I don't know if I understand your question correctly, but if you just wanna avoid namespace conflict in that specific function, why not import it inside the function?

def foo(bar=42):
  from package import bar as package_bar
  do_something_with_bar(package_bar(bar))

And you can add one line comment at top to remind yourself.

Upvotes: 0

Victor Sales
Victor Sales

Reputation: 1

You could use the globals() to reference global variables.

def foo(bar=42):
    package_bar = globals()['bar']
    do_something_with_bar(package_bar(bar))

This shouldn't break anything in your code base.

Upvotes: -1

B. Go
B. Go

Reputation: 1424

If you're lucky, the foo function is only called by "foo()" or "foo(24)" and nowhere by "foo(bar=42)" and then you can put any new name instead of bar without breaking anything.
Else you have to grep / search for all calls of "foo(bar=" and replace them too, being careful of the possible extra spaces like in "foo( bar =".

Upvotes: 0

cs95
cs95

Reputation: 402982

This is a common issue. In this case, it helps to have an additional import statement for package, so you can safely refer to package's bar through the package namespace without running into naming conflicts.

import package
from package import bar

def foo(bar=42):
    do_something_with_bar(package.bar(bar))

You still end up importing the module once, but you now have two ways of referring to bar.

Upvotes: 7

Dan D.
Dan D.

Reputation: 74675

Replace the function body with a call to another function with differently named arguments:

from package import bar

def foo(bar=42):
    return _foo(baz=bar)

def _foo(baz):
    do_something_with_bar(bar(baz))

Then you are free to use bar in that function as the name of the function from the package rather than the argument.

Upvotes: 2

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