how to create a nested dictionary in python

Prerequisite – Python dictionary

A Dictionary in Python works similar to the Dictionary in the real world. Keys of a Dictionary must be unique and of immutable data type such as Strings, Integers and tuples, but the key-values can be repeated and be of any type.

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Nested Dictionary: Nesting Dictionary means putting a dictionary inside another dictionary. Nesting is of great use as the kind of information we can model in programs is expanded greatly.

nested_dict = { 'dict1' : { 'key_A' : 'value_A' },

'dict2' : { 'key_B' : 'value_B' }}

Dict = { 1 : 'Geeks' , 2 : 'For' , 3 : { 'A' : 'Welcome' , 'B' : 'To' , 'C' : 'Geeks' }}

Creating a Nested Dictionary

In Python, a Nested dictionary can be created by placing the comma-separated dictionaries enclosed withing braces.

Dict = { 'Dict1' : { },

'Dict2' : { }}

print ( "Nested dictionary 1-" )

print ( Dict )

Dict = { 'Dict1' : { 'name' : 'Ali' , 'age' : '19' },

'Dict2' : { 'name' : 'Bob' , 'age' : '25' }}

print ( "\nNested dictionary 2-" )

print ( Dict )

Dict = { 'Dict1' : { 1 : 'G' , 2 : 'F' , 3 : 'G' },

'Dict2' : { 'Name' : 'Geeks' , 1 : [ 1 , 2 ]} }

print ( "\nNested dictionary 3-" )

print ( Dict )

Output:

Nested dictionary 1- {'Dict1': {}, 'Dict2': {}}  Nested dictionary 2- {'Dict1': {'name': 'Ali', 'age': '19'}, 'Dict2': {'name': 'Bob', 'age': '25'}}  Nested dictionary 3- {'Dict1': {1: 'G', 2: 'F', 3: 'G'}, 'Dict2': {1: [1, 2], 'Name': 'Geeks'}}

Adding elements to a Nested Dictionary

Addition of elements to a nested Dictionary can be done in multiple ways. One way to add a dictionary in the Nested dictionary is to add values one be one, Nested_dict[dict][key] = 'value'. Another way is to add the whole dictionary in one go, Nested_dict[dict] = { 'key': 'value'}.

Dict = { }

print ( "Initial nested dictionary:-" )

print ( Dict )

Dict [ 'Dict1' ] = {}

Dict [ 'Dict1' ][ 'name' ] = 'Bob'

Dict [ 'Dict1' ][ 'age' ] = 21

print ( "\nAfter adding dictionary Dict1" )

print ( Dict )

Dict [ 'Dict2' ] = { 'name' : 'Cara' , 'age' : 25 }

print ( "\nAfter adding dictionary Dict1" )

print ( Dict )

Output:

Initial nested dictionary:- {}  After adding dictionary Dict1 {'Dict1': {'age': 21, 'name': 'Bob'}}  After adding dictionary Dict1 {'Dict1': {'age': 21, 'name': 'Bob'}, 'Dict2': {'age': 25, 'name': 'Cara'}}

Access elements of a Nested Dictionary

In order to access the value of any key in nested dictionary, use indexing [] syntax.

Dict = { 'Dict1' : { 'name' : 'Ali' , 'age' : '19' },

'Dict2' : { 'name' : 'Bob' , 'age' : '25' }}

print ( Dict [ 'Dict1' ][ 'name' ])

print ( Dict [ 'Dict2' ][ 'age' ])

Output:

Ali 25

Deleting dictionaries from a Nested Dictionary

Deletion of dictionaries from a nested dictionary can be done either by using del keyword or by using pop() function.

Dict = { 'Dict1' : { 'name' : 'Ali' , 'age' : 19 },

'Dict2' : { 'name' : 'Bob' , 'age' : 21 }}

print ( "Initial nested dictionary:-" )

print ( Dict )

print ( "\nDeleting Dict2:-" )

del Dict [ 'Dict2' ]

print ( Dict )

print ( "\nDeleting Dict1:-" )

Dict .pop( 'Dict1' )

print ( Dict )

Output:

Initial nested dictionary:- {'Dict2': {'name': 'Bob', 'age': 21}, 'Dict1': {'name': 'Ali', 'age': 19}}  Deleting Dict2:- {'Dict1': {'name': 'Ali', 'age': 19}}  Deleting Dict1:- {}