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Python Python Collections (Retired) Dictionaries String Formatting with Dictionaries

Jonathan Shedd
Jonathan Shedd
1,921 Points
Posted by Jonathan Shedd
Jonathan Shedd
1,921 Points

A KeyError?

I need to create a function that takes in a string and list of dictionaries and will then proceed to return a new list that uses the format() function to unpack the dictionaries and integrate them into the string. However, I know that there is something wrong with this code and I keep getting a KeyError. All help is appreciated! :)

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):
    for item in dicts:
        return(list(string.format(dicts)))

1 Answer

jacinator
jacinator
11,936 Points

Here's two functions that will work. The first is a bit simpler, the second is shorter and more Pythonic if you are familiar with list comprehension. I can't remember if that's later or earlier in the course. You're getting the KeyError because you aren't unpacking the dictionary into format so format is getting a dictionary instead of keyword arguments to feed into the sentence. The other bug that you have is the return inside of the forloop. That won't work for you, as it will only return the first item in the loop.

def string_factory(dictionaries, string):
    return_list = []
    for dictionary in dictionaries:
        return_list.append(string.format(**dictionary))
    return return_list

# List comprehension
def string_factory(dictionaries, string):
    return [string.format(**dictionary) for dictionary in dictionaries]
Jonathan Shedd
Jonathan Shedd
1,921 Points
Jonathan Shedd
Jonathan Shedd
1,921 Points

I haven't quite gotten to list comprehensions yet. But I understand what I was doing wrong now. Thanks!