How to change value of arguments in Python3

Question

I want to pass n variables to a function in python and have the function sanitize these variables. My first attempt at this was

list_of_variables = [a, b, c,]
def sanitize(*args):
    for arg in args:
        arg = str(arg) #example
sanitize(*list_of_variables)

but arg becomes a local variable and the original array remains unaffected.

Attempt#2

for arg in args:
    global arg

but this didnt work since arg is assigned before global declaration. putting global arg above the loop also didnt work.

is there a way to make this function perform a certain action over n variables.

Answer 1

if you put your var(s) in a list, there is no need to use indirection, just read the list in sanitize :

a=10
b= 12/3
c= "ABCDEF"

list_of_variables = [a, b, c]

def sanitize(aList):
    for i in range (0, len(aList)):
        aList[i] = str(aList[i])

sanitize(list_of_variables)
print(list_of_variables)

result : ['10', '4.0', 'ABCDEF']

But this will not work with sanitize(a,b,c) as python creates a tuple, not a list and a tuple cannot be modified;

if you want to use sanitize with a free list of var(s), you must return something else than the initial tuple. A code could be :

def sanitize(*args):
    aList=[]
    for arg in args:
        aList.append(str(arg))
    return aList

result = sanitize(a,b,c)
print(result)

You get : ['10', '4.0', 'ABCDEF']

But take care that in any case of these examples, a, b or c stay unchanged. print (a,b,c) will always give 10 4.0 ABCDEF

You are not manipulating pointers as it could be in C !

HTH