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

Posted by linda wu
linda wu
3,016 Points

Unpacking dictionary

dict = {'name': 'Michelangelo', 'food' : 'PIZZA'} def favorite_food(name = 0, food = 0): if (name and food): result = "Hi, I'm {} and I love to eat {}!".format(name, food) return result

print favorite_food(**dict)

string_factory.py 
dict = {'name': 'Michelangelo', 'food' : 'PIZZA'}
def favorite_food(name = 0, food = 0):
    if (name and food):
        result = "Hi, I'm {} and I love to eat {}!".format(name, food)
        return result

favorite_food(**dict)
linda wu
linda wu
3,016 Points

Hi,

I don't understand why this is failing for me. I ran the code in Pycharm and it works totally fine. However, it is always failing in treehouse. Someone please help me to understand why it is not working. Thanks

5 Answers

Mark Kastelic
Mark Kastelic
8,147 Points
Mark Kastelic
Mark Kastelic
8,147 Points

Hi Linda,

Your solution works as written, but the challenge states that the function must accept a dictionary. Your function currently has two keyword arguments. When you call it by passing **dict, you are unpacking dict to fill in the two keyword arguments. That works. But, to set up the function to actually accept a dictionary object directly, you have to do something like this:

def favorite_food(dict):
    values = []
    for item in dict.items():
        values.append(item[1])
    return "Hi, I'm {name} and I love to eat {food}!".format(name=values[0], food=values[1])
linda wu
linda wu
3,016 Points
linda wu
linda wu
3,016 Points

Cool, thanks Mark for your explanation! I got it now.

Dave StSomeWhere
Dave StSomeWhere
19,870 Points
Dave StSomeWhere
Dave StSomeWhere
19,870 Points

I'm pretty sure that the goal of the challenge is to understand the spiffy feature unpacking a dictionary while passing it to the format() function call.

So while the code above works, the unpacking feature makes it much simpler - no need to loop and append into a list.

Here's the code using unpacking 

def favorite_food(dict):
    return "Hi, I'm {name} and I love to eat {food}!".format(**dict)
linda wu
linda wu
3,016 Points
linda wu
linda wu
3,016 Points

This is really neat Dave! I love it.

Mark Kastelic
Mark Kastelic
8,147 Points
Mark Kastelic
Mark Kastelic
8,147 Points

You are right, unpacking should be retained in the challenge. Thanks for that beautiful Pythonic refinement! I will now go back to my REPL and "import this" ten times :).

linda wu
linda wu
3,016 Points
linda wu
linda wu
3,016 Points

I do spent good amount of time to complete this challenge. I think the instructor's intension was understand both dictionary unpacking as well as string.format function with python. However, the video was not very tailor made to tackle this challenge and it seems made a lot of people stumble on this question.

I found this link is quite helpful. https://www.python-course.eu/python3_formatted_output.php

Dave StSomeWhere
Dave StSomeWhere
19,870 Points
Dave StSomeWhere
Dave StSomeWhere
19,870 Points

Nice link thanks, those place holders are always confusing to me, so I rarely use them and have to look them up all the time - :tropical_drink: