Question

The following script produces a “local variable ‘var’ referenced before assignment” error:

def func1():
    var = var + 1

var = 1

func1()

How would you suggest to correct the code? Why does this error occur when the variable is declared in the script before the function is called?

Answer 1

You can use a global variable in other functions by declaring it as global in each function that modifies it:

>>> var = 2
>>> def func():
...     global var
...     var = var+1
...     return var
... 
>>> func()
3

After OP edited question:
If you are moving the variable after you define the function you will need to pass it to the function as a parameter.

>>> def func(var):
...     var = var+1
...     return var
... 
>>> var = 2
>>> func(var)
3