Creating a tuple out of *args

Question

I've tried, but I can't figure this out so far. I want to create a list of tuples, each one built out of dictionary values:

my_list = [(x['field1'], x['field2']) for x in my_dict]

But the issue is that I want to do this inside a function, passing the fields I want to get to *args:

my_func('field1', 'field2')

How can I build the first list comprehension out of the *args list?

Thanks!

I'll try to clarify:

Briefly, what I want to do is map this:

my_func('field1', 'field2')

To this:

tuple(x['field1'], x['field2'])

Which will be a statement inside my_func(*args)

Not so clear what you want to do. Can you give an example (or two) with the input/output you want? — Dekel, Dec 07 '16 at 23:24
Unclear ... what is `my_dict` in this ... a list of dictionaries? Are you wanting to get a different field from each element of `my_dict`? — donkopotamus, Dec 07 '16 at 23:25
Like what exactly are you asking? Creating tuples from function arguments? So you want function which will return tuple ? — pagep, Dec 07 '16 at 23:25
`*args` **already creates a tuple** - `args`, inside the function, would be `('field1', 'field2')` — jonrsharpe, Dec 07 '16 at 23:31

score 1 · Accepted Answer · answered Dec 07 '16 at 23:31

You can create a tuple by doing another comprehension over the args:

def my_func(*args):
    return [tuple(x[arg] for arg in args) for x in my_dict]

However this assumes that your my_dict is a global variable. But now you can call it like you specified with my_func('field1', 'field2').

I would advise to add the dictionary to the function definition:

def my_func(my_dict, *args):
    return [tuple(x[arg] for arg in args) for x in my_dict]

and call it as my_func(my_dict, 'field1', 'field2')

It's ok, in fact the function is more complex, and includes the dictionary. I made it simpler so the question is clearer. Thanks again! — Ivan, Dec 07 '16 at 23:43

score 0 · Answer 2 · answered Dec 07 '16 at 23:28

0

Simply refer to those arguments as normal:

def f(d, a, b):
    return [(x[a], x[b]) for x in d]

result = f(my_dict, 'field1', 'field2')

answered Dec 07 '16 at 23:28

TigerhawkT3

2 Answers2