How to change variable in function scope from inner function

Question

Same code will work in JS, but in python it will not change variable, how do you change variables in nested functions? Thanks in advance and sorry for noob question

   def sample():
       a = False
       def sample2():
           a = True
       sample2()
       return a

Consider redesign, so `nonlocal` is not necessary. The break of encapsulation makes maintenance difficult ... a problem I personally have with `js`. — Dr. V, Jun 06 '20 at 14:45
To be fair, it's not possible to know it's a duplicate before you know the answer to this question. It's as if one asks: "*What is 6x7*", and somebody says: "*Duplicate, here is already a post about 42!*" — Dr. V, Jun 06 '20 at 14:55

score 3 · Accepted Answer · answered Jun 06 '20 at 14:43

3

Use nonlocal to modify variables outside the scope of the function.

   def sample():
       a = False
       def sample2():
           nonlocal a
           a = True
       sample2()
       return a

answered Jun 06 '20 at 14:43

paltaa

2,985
13
28

score 2 · Answer 2 · answered Jun 06 '20 at 14:44

use nonlocal

def sample():
    a = False
    def sample2():
        nonlocal a
        a = True
    sample2()
    return a

Python 3 docs

The nonlocal statement causes the listed identifiers to refer to previously bound variables in the nearest enclosing scope excluding globals.

score 2 · Answer 3 · answered Jun 06 '20 at 14:45

2

 def sample():
       a = False
       def sample2():
           nonlocal a
           a = True
       sample2()
       return a

This should work.

answered Jun 06 '20 at 14:45

Hasibul Islam Polok

105
8

How to change variable in function scope from inner function

3 Answers3