Python: Referencing/Assignment with Local/Global Variable within Loop

Question

I have the following loop structure and also the problem, that it is not possible to increment a variable inside of this code due to UnboundLocalError:

while True:
    def function_1():
        def function_2():
            x += 1
            print(x)
        function_2()
    function_1()

My solution was now this one:

x = 0
while True:
    def function_1():
        def function_2():
            global x
            x += 1
            print(x)
        function_2()
    function_1()

Is there another solution without global?

vks · Accepted Answer · 2017-02-22 07:36:07Z

1

use a mutable value.

x = []
x.append(0)
while True:
    def function_1():
        def function_2():
            x[0]= x[0]+1
            print x[0]
        function_2()
    function_1()

answered Feb 22, 2017 at 7:36

vks

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1 Comment

sunwarr10r Over a year ago

Thank you! I will test which one is faster.

Jonathan · Accepted Answer · 2017-02-22 08:01:02Z

1

Pass and return x to all the functions.

x = 0
while True:
    def function_1(x1):
        def function_2(x2):
            x2 += 1
            print(x2)
            return x2
        return function_2(x1)
    x = function_1(x)

answered Feb 22, 2017 at 8:01

Jonathan

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