function that modifies global variable of my choice

[joananon]

Hi everybody! I don't know if this is possible to do, but here goes:

Hi have a program where I have several lists. Let's call them l1, l2, l3, l4.
Often in the code, I need to delete a certain item from 2 of the lists I have.
I thought about defining a function that only needs to know which lists I want to modify and what item to delete from them.

def myfunction(myl1's_globalname,myl2's_globalname, itemtodelete):
    global myl1's_globalname

The problem is that if I use things like "global myl1's_globalname" when defining the function, I'll have an error saying that global and local variables have the same name.
Isn't there a way to do this such that in the function arguments I write the name of the lists I want to modify and the function makes "global (variable whose name corresponds to 1st argument in the function)"?

thanks in advance!
joana

[vegaseat]

No need to use global since lists are mutable objects and are passed by reference to a function. Here is an example ...

def remove_item(list1, list2, item):
    """lists are passed by reference so items are removed in place"""    
    if item in list1:
        list1.remove(item)
    if item in list2:
        list2.remove(item)


q1 = ['w', 'a', 'r', 'm']
q2 = ['w', 'a', 't', 'e', 'r', 'y']
q3 = ['l', 'a', 'r', 'g', 'e']
q4 = ['g', 'a', 'r', 'd', 'e', 'n']

print(q1)
print(q2)
remove_item(q1, q2, 'a')
print('-'*10)
print(q1)
print(q2)

"""
my output -->
['w', 'a', 'r', 'm']
['w', 'a', 't', 'e', 'r', 'y']
----------
['w', 'r', 'm']
['w', 't', 'e', 'r', 'y']
"""

Now remember that remove() only removes the first matching item it encounters in each list.

[joananon]

Thanks Vega Seat!
I feel like such a rookie... it's so much simpler than I thought.
Problem solved!