Welcome to the Treehouse Community

Want to collaborate on code errors? Have bugs you need feedback on? Looking for an extra set of eyes on your latest project? Get support with fellow developers, designers, and programmers of all backgrounds and skill levels here with the Treehouse Community! While you're at it, check out some resources Treehouse students have shared here.

Looking to learn something new?

Treehouse offers a seven day free trial for new students. Get access to thousands of hours of content and join thousands of Treehouse students and alumni in the community today.

Start your free trial

Python Python Collections (2016, retired 2019) Dictionaries String Formatting with Dictionaries

Posted by Mohammad Zryab
Mohammad Zryab
4,109 Points

Why are we unpacking the items in the for loop and not the actual dictionary?

Here is my code:

# Example:
# values = [{"name": "Michelangelo", "food": "PIZZA"}, {"name": "Garfield", "food": "lasagna"}]
# string_factory(values)
# ["Hi, I'm Michelangelo and I love to eat PIZZA!", "Hi, I'm Garfield and I love to eat lasagna!"]

template = "Hi, I'm {name} and I love to eat {food}!"
values = [{"name": "Michelangelo", "food": "PIZZA"}, {"name": "Garfield", "food": "lasagna"}]

def string_factory(values):
    new_list = []
    for things in values:
        new_list.append(template.format(**things))
    return new_list

My question here is, in the for loop why are using "**" for things and not for values? Because things is not a dictionary that we can unpack whereas values is.

1 Answer

Chris Freeman
MOD
Chris Freeman
Treehouse Moderator 68,441 Points
Chris Freeman
Chris Freeman
Treehouse Moderator 68,441 Points

values is a list that cannot be unpacked with "**". The double-asterisk is used to turn the things dictionary into the key/value pairs needed for the format statement. The if statement will automatic iterate over the values list.

Mohammad Zryab
Mohammad Zryab
4,109 Points

Got it - completely overlooked that values was a list.