CODEWITHSUNDEEP
python
user3014653
user3014653

Reputation: 775

Use of python getattr/setattr for current function

Is it possible to use getattr/setattr to access a variable in a class function?

Example below. Say I have a class A, that has two methods, func1 and func2 both of which define a variable count of a different type. Is there a way to use getattr in func2 to access the local variable count?

In reality, I have quite a few variables in func2 (that are also defined differently in func1) that I want to loop through using getattr and I'm looking to shorten up my code a bit by using a loop through the variable names. 

class A(object):

   def __init__(self):
      pass

   def func1(self):
        count = {"A": 1, "B":2}

   def func2(self):
        count = [1, 2]
        mean = [10, 20]
        for attr in ("count", "mean"):
           xattr = getattr(self, attr)   ! What do I put in here in place of "self"?
           xattr.append(99)

Upvotes: 15

Views: 15331

Answers (2)

Thomas Guyot-Sionnest
Thomas Guyot-Sionnest

Reputation: 2520

This has been answered before on Stackoverflow... In short:

import sys

getattr(sys.modules[__name__], attr)

Edit: you can also look up and update the dict returned by globals() directly, ex. this is roughly equivalent to the getattr() above:

globals()[attr]

Upvotes: 17

Martijn Pieters
Martijn Pieters

Reputation: 1124548

No, getattr() and setattr() only work with attributes on an object. What you are trying to access are local variables instead.

You can use locals() to access a dictionary of local names:

for name in ("count", "mean"):
    value = locals()[name]
    value.append(99)

but it'd be better just to name the lists directly, there is no need to go through such trouble here:

for value in (count, mean):
    value.append(99)

Upvotes: 21

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