CODEWITHSUNDEEP
python
Zamaroht
Zamaroht

Reputation: 150

Convert function arguments to lists

I have a function with a definite set of arguments, but that during development the amount of arguments it recieves could change. Each argument can either be a string, or a list. I want to someway loop trough the arguments of the function, and if they are a string, convert them to a list with that single element.

I tried using locals() to be able to loop trough the arguments, but I don't know how to modify the value during the iteration, so I guess that's not the correct approach:

def function(a, b, c, d):
    for key in locals():
        if type(key) == str:
            # ??? key = list(locals[key])

    # ... more code over here, assuming that a,b,c,d are lists

What's the correct way to acomplish this?

Thanks!

Upvotes: 1

Views: 1456

Answers (3)

Bhargav Rao
Bhargav Rao

Reputation: 52191

You can use isinstance(key, str) to check if a variable is a str or not

def function(a, b, c, d):
    l= locals()
    for i in l:
        key = l[i]
        if isinstance(key, str):
            l[i] = [l[i]]
    l = l.values()
    print (l)
function('one', 'two', ['bla','bla'], ['ble'])

If you want list, then you need to have a line

 l = l.values()

This will be

[['a'], ['c'], ['b'], ['d']]

EDIT: As you have suggested, the correct program is

def function(a, b, c, d):
    l= locals()
    dirty= False
    for i in l:
        key = l[i]
        if isinstance(key, str):
            l[i] = [l[i]]
            dirty= True
    if dirty:
        function(**l)
    else:
        print a, b, c, d
    print (l)

function('one', 'two', ['bla','bla'], ['ble'])

This will output

['one'], ['bla', 'bla'], ['two'], ['ble']

Upvotes: 1

hariK
hariK

Reputation: 3069

def function(*args):

    arg_list = list(args)
    for i in range(len(arg_list)):
        if type(arg_list[i]) == str:
            #Do the stuff
        elif type(arg_list[i]) == list:
            #Do the stuff
        else:
            #Do the stuff

function ('a','b', ['c', 'd', 'e'])

Upvotes: 0

Reut Sharabani
Reut Sharabani

Reputation: 31349

Use *args or **kwargs:

def use_args(*args):
    # covert strings to `list` containing them
    new_args = map(lambda x: [x] if isinstance(x, str) else x, args)
    return new_args
print use_args([1, 2], "3")

Output:

[[1, 2], ['3']]

Upvotes: 1

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