Creating a Dictionary in Python

Dictionary is similar to a list. It contains key:value pairs. Here, we will learn about creating and modifying dictionaries.
Creating Dictionary
dictionary_name = {key:value, key:value,…..}

We create a dictionary with colors of jams as keys and fruit names as values.

jam = {'red':'strawberry', 'yellow': 'mango', 'orange':'orange'}
print jam['orange']
print jam['red']

orange
strawberry

Insertion – Here, we add a new key/value pair to the existing dictionary.

jam['blue'] = 'blueberry'

{‘blue’: ‘blueberry’, ‘red’: ‘strawberry’, ‘yellow’: ‘mango’, ‘orange’: ‘orange’}

Deletion – Here, we delete a key/value pair

del jam['orange']
jam

{‘blue’: ‘blueberry’, ‘red’: ‘strawberry’, ‘yellow’: ‘mango’}

Replacing values – We replace value for key ‘red’ from strawberry to cherry.

jam ['red'] = 'cherry'
jam

{‘blue’: ‘blueberry’, ‘red’: ‘cherry’, ‘yellow’: ‘mango’}

Nesting : We nest a new dictionary within an existing dictionary.

 jam['red'] = {'light' : 'cherry', 'dark' : 'strawberry' }

{‘blue’: ‘blueberry’, ‘red’: {‘dark’: ‘strawberry’, ‘light’: ‘cherry’}, ‘yellow’: ‘mango’}
We set a list as a value for key ‘blue’.

jam['blue'] = ['blueberry','plum']
jam

{‘blue’: [‘blueberry’, ‘plum’], ‘red’: {‘dark’: ‘strawberry’, ‘light’: ‘cherry’}, ‘yellow’: ‘mango’}

Append to a list

jam['blue'].append('jamun')  
print jam['blue']

[‘blueberry’, ‘plum’, ‘jamun’]

Indexing the nested dictionary

print jam['red']['dark']

strawberry

jam

{‘blue’: [‘blueberry’, ‘plum’, ‘jamun’], ‘red’: {‘dark’: ‘strawberry’, ‘light’: ‘cherry’}, ‘yellow’: ‘mango’}

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