CODEWITHSUNDEEP
pythonpython-3.x
Jonas Graffman
Jonas Graffman

Reputation: 97

Create a function that returns a new dictionary

I want to write a function that takes in a dictionary as an input and returns a new dictionary. In the new dictionary I would like to use the same keys as in the old one, but I've got new values.

This is my old dictionary:

animals = {'tiger': ['claws', 'sharp teeth', 'four legs', 'stripes'],
           'elephant': ['trunk', 'four legs', 'big ears', 'gray skin'],
           'human': ['two legs', 'funny looking ears', 'a sense of humor']
           }

Then I'm creating a function that takes in the old dictionary and I want it to keep the keys but change values (the new values should pass through a function called bandit. It looks something like this.

def myfunction(animals):
    new_dictionary = {}

    for key in animals.keys():
        new_dictionary = {key: []}


        for value in animals[key]:
            bandit_animals = bandit_language(value)
            new_dictionary = {key: bandit_animals}

    return new_dictionary


print(myfunction(animals))

The function only prints the last key and the last value and I want it to print a whole dictionary.

Can anyone explain?

Upvotes: 4

Views: 148

Answers (3)

najeem
najeem

Reputation: 1921

You could do the whole thing in a single line.

print({k: bandit_language(v) for k, v in animals.items()})

For demo, if I substitute bandit_language function with len.

print({k: len(v) for k, v in animals.items()})
Out: {'elephant': 4, 'human': 3, 'tiger': 4}

Upvotes: 0

DocDriven
DocDriven

Reputation: 3974

A more compact way of doing this by using items():

animals = {'tiger': ['claws', 'sharp teeth', 'four legs', 'stripes'],
           'elephant': ['trunk', 'four legs', 'big ears', 'gray skin'],
           'human': ['two legs', 'funny looking ears', 'a sense of humor']
           }

# some dummy function
def bandit_language(val):
    return 'Ho ho ho'


def myfunction(animals):
    return {key: [bandit_language(val) for val in lst] for key, lst in animals.items()}

print(myfunction(animals)

This produces:

{'human': ['Ho ho ho', 'Ho ho ho', 'Ho ho ho'], 'tiger': ['Ho ho ho', 'Ho ho ho', 'Ho ho ho', 'Ho ho ho'], 'elephant': ['Ho ho ho', 'Ho ho ho', 'Ho ho ho', 'Ho ho ho']}

Upvotes: 0

Josh Friedlander
Josh Friedlander

Reputation: 11657

You're initialising a blank dictionary again at every pass through the loop.

This should work:

def myfunction(animals):
    new_dictionary = {}

    for key in animals.keys():
        new_dictionary[key] = []

        for value in animals[key]:
            bandit_animals = bandit_language(value)
            new_dictionary[key].append(bandit_animals)

    return new_dictionary


print(myfunction(animals))

Upvotes: 1

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