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Creating a Dictionary

Dictionaries are used to store data values in key:value pairs.

Dictionaries are one of 4 built-in data types in Python used to store data values in key:value pairs, the other 3 are Tuple, Set, and List, all with different qualities and usage.

Dictionaries are written with Curly Brackets, and have keys and values:

Dict.py
myDict = {}  # This is an empty dictionary
print(myDict)

Note

As of Python version 3.7, dictionaries are ordered. In Python 3.6 and earlier, dictionaries are unordered.

The Basic Method​

Dict_Basics.py
Dict = {1: 'Geeks', 2: 'For', 3: 'Geeks'}
print(Dict)

The dict() Constructor​

Create a file Dict_Constructor.py

It is also possible to use the dict() constructor when creating a new dictionary.

Dict_Constructor.py
# Using key-value pairs as arguments
MyDict = dict(name='Shashank', Roll=12217166, Age=21)
print(MyDict)

# Using iterable of key-value pairs
MyList=[('key1', 'value1'), ('key2', 'value2'), ('key3', 'value3')]
MyDict1 = dict(MyList)
print(MyDict1)

Creating an Empty Dictionary​

Create a file EmptyDict.py

An Empty Dictionary can be created in two ways:

  1. Using Empty Curly Braces

EmptyDict.py
myDict = {}

  1. By Dictionary Constructor

EmptyDict1.py
myDict = dict()

Creating a Nested Dictionary​

Create a file NestedDict.py

A nested list is made up of a series of sublists separated by commas.

NestedDict.py
nested_dict = {
    'person1': {
        'name': 'Alice',
        'age': 30,
        'city': 'New York'
    },
    'person2': {
        'name': 'Bob',
        'age': 25,
        'city': 'Los Angeles'
    }
}

print(nested_dict['person1']['name']) 
print(nested_dict['person2']['age'])

Output
Alice
25