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Python Python Collections (Retired) Dictionaries String Formatting with Dictionaries

Posted by David Wright
David Wright
4,437 Points

Formatting strings with dicts -

So after reading Chris's Forum Solution to another persons (long script) I was able to come to this code as a correct solution. However, I still don't totally get why it worked.

Will this " **iterable_dict " stuff become more clear as I continue or am I missing the boat?

Thanks!

strings.py 
dicts = [
    {'name': 'Michelangelo',
     'food': 'PIZZA'},
    {'name': 'Garfield',
     'food': 'lasanga'},
    {'name': 'Walter',
     'food': 'pancakes'},
    {'name': 'Galactus',
     'food': 'worlds'}
]

string = "Hi, I'm {name} and I love to eat {food}!"


def string_factory(dicts, string):
  new_list = []
  for itble_dict in dicts:
    new_string = string.format(**itble_dict)
    new_list.append(new_string)
  return new_list

1 Answer

Chris Freeman
MOD
Chris Freeman
Treehouse Moderator 68,423 Points
Chris Freeman
Chris Freeman
Treehouse Moderator 68,423 Points

The double-asterisks can be used as a parameter to receive an arbitrary number of keyword arguments and store in a dict.

Given a function:

def func(**args):
    pass

was called with (name='Michelangelo', food='PIZZA') then within func, args would be equivalent to

{'name': 'Michelangelo', 'food': 'PIZZA'}

It can also be used, with a dict, as an argument to "unpack" the dictionary into an equivalent keyword arguments.

if iterable_dict is {'name': 'Michelangelo', 'food': 'PIZZA'} then **iterable_dict would expand to:

name='Michelangelo', food='PIZZA'

Post back if this is not clear.