Python - How to create a dictionary, add to it and access it

In Python, a dictionary is a collection of key-value pairs, where each key is unique. Dictionaries are great as "lookups" as they are implemented using hash tables. To create a dictionary, you can use curly braces {} and separate keys and values with a colon.

For example:

my_dict = {'key1': 'value1', 'key2': 'value2'}

You can also use the built-in dict() method to create a dictionary:

my_dict = dict(key1='value1', key2='value2')

To access the values in a dictionary, you can use the keys in square brackets, like so:

print(my_dict['key1']) # Output: 'value1'

You can also use the get() method to access the values, which will return None if the key is not found in the dictionary:

print(my_dict.get('key3')) # Output: None

You can add new key-value pairs to the dictionary using the assignment operator:

my_dict['key3'] = 'value3'

You can also update the value of an existing key using the assignment operator:

my_dict['key2'] = 'new_value'

You can also use the update() method to add multiple key-value pairs at once:

my_dict.update({'key4': 'value4', 'key5': 'value5'})

You can remove key-value pairs from a dictionary using the del keyword or the pop() method:

del my_dict['key1']

You can iterate through keys and values in a dictionary using a .items() call:

for key, value in my_dict.items():
    print(key, value)

And you can check the length of dictionary by using the .len() method


That is all

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