Goal

I am trying to write a function where one or more of the input parameters is a global variable that is updated by the function, without having to return values from within the function. I am aware I could just return a tuple or two separate values from the function, but I think updating the global variables from within the function would be another interesting method if it is possible.

Reason to do this

Updating global variables with a function is easy when the global variable is known (ie. defined previously in the python script). However, I want to define the function in a separate .py file to easily use the function within other python scripts. Therefore, I need to be able to support different variable names to update.

While this is not at all necessary, I am just interested if this is even possible.

Example Pseudocode

I'm thinking something like this:

def math_function(input_val, squared_result, cubed_result):
    squared_result = input_val**2 #update the var input as the squared_result parameter
    cubed_result = input_val**3 #update the var input as the cubed_result parameter

where you would input a number for input_val and then global variables for squared_result and cubed_result that the function updates with the result. It would then theoretically work like:

#Declare global variables
b = 0
c = 0

#then somewhere in the code, call the function
math_function(2, b, c)

#check the new values
print(b) #Output: b = 4
print(c) #Output: c = 8

This would allow me to use the function in different python scripts without having to worry about what order the results are returned in.

CodePudding user response：

First: I am in no way advocating this.

You could use the globals builtin function to access a global variable by name:

def gtest(name,value):
    globals()[name] = value

gtest('new_global','new_value')
print(new_global)

CodePudding user response：

"""
Modify globals
"""

b = 0
c = 0


def math_function(input_val, global_name_1, global_name_2):
    globals()[
        global_name_1] = input_val ** 2  # update the var input as the squared_result
    # parameter
    globals()[global_name_2] = input_val ** 3  # update the var input as the
    # cubed_result parameter


math_function(2, 'b', 'c')
print(b)
print(c)

Output

4
8