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Python Python Collections (Retired) Dictionaries String Formatting with Dictionaries

Posted by Wolverine .py
Wolverine .py
2,513 Points

create a function that will return a string which has a dictionary added at the end

the list i have created doesn't have the correct output

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 = ()
  new_list = list("Hi, I'm {} and I love to eat {}! ".format("Michelangelo, Garfield, Walter, Galactus", "PIZZA, lasanga, pancakes, worlds"))

  return new_list

2 Answers

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

Your code is missing some key elements:

def string_factory(dicts, string):
    # Start with Blank list
    new_list = []
    #loop over each dictionary listed in "dicts"
    for each_dict in dicts:
        # the string variable uses named fields.
        # populate these named fields in string with the values using the values in each_dict
        outstring = string.format(name=each_dict['name'], food=each_dict['food'])
        # append new outstring to new_list
        new_list.append(outstring)
    # return completed new_list
    return new_list

These statements can be compress to:

def string_factory(dicts, string):
  new_list = []
  for each_dict in dicts:
      new_list.append(string.format(name=each_dict['name'], food=each_dict['food']))
  return new_list
Jason Anello
Jason Anello
Courses Plus Student 94,610 Points

It would be easier to unpack the dictionary that you have especially if you had more keys.

new_list.append(string.format(**each_dict))
Chris Freeman
Chris Freeman
Treehouse Moderator 68,441 Points
Chris Freeman
Chris Freeman
Treehouse Moderator 68,441 Points

Agreed. Sometimes the ** notation can be overwhelming or muddle the key concepts being taught for newer students. There is also the caveats for using unpacking, like in this case, what if the each_dict had more than the two keys needed for the format:

In [1]: newdict = {'name': 'Bunny', 'food': 'carrots', 'advisary': 'Fudd'}

In [2]: "Hi, I'm {} and I love to eat {}! ".format(**newdict)
---------------------------------------------------------------------------
IndexError                                Traceback (most recent call last)
<ipython-input-2-601979dbf0b3> in <module>()
----> 1 "Hi, I'm {} and I love to eat {}! ".format(**newdict)

IndexError: tuple index out of range
Wolverine .py
Wolverine .py
2,513 Points
Wolverine .py
Wolverine .py
2,513 Points

Thank you Chris and Jason, i had forgotten the looping. I will practice more.

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

I wanted to comment about your question title. If by "a string with a dictionary at the end" you mean the curly brackets inside the string, those not there to represent a dictionary.

The use of {} in python syntax has multiple meanings. The main one as you mention is to indicate a dictionary. Additionally,{} are used in regular expression syntax, and as in this case they are used as fields for the str.format() method.