Add a key:value pair to dictionary in Python

Dictionary in Python is an unordered collection of data values, used to store data values like a map, which unlike other Data Types that hold only single value as an element, Dictionary holds key:value pair.

While using Dictionary, sometimes, we need to add or modify the key/value inside the dictionary. Let’s see how to add a key:value pair to dictionary in Python.

Code #1: Using Subscript notation

This method will create a new key:value pair on a dictionary by assigning a value to that key.

# Python program to add a key:value pair to dictionary

dict = {'key1':'geeks', 'key2':'for'}
print("Current Dict is: ", dict)

# using the subscript notation
# Dictionary_Name[New_Key_Name] = New_Key_Value

dict['key3'] = 'Geeks'
dict['key4'] = 'is'
dict['key5'] = 'portal'
dict['key6'] = 'Computer'
print("Updated Dict is: ", dict)

Output:

Current Dict is: {‘key2’: ‘for’, ‘key1’: ‘geeks’}
Updated Dict is: {‘key3’: ‘Geeks’, ‘key5’: ‘portal’, ‘key6’: ‘Computer’, ‘key4’: ‘is’, ‘key1’: ‘geeks’, ‘key2’: ‘for’}

Code #2: Using update() method

dict = {'key1':'geeks', 'key2':'for'}
print("Current Dict is: ", dict)

# adding dict1 (key3, key4 and key5) to dict
dict1 = {'key3':'geeks', 'key4':'is', 'key5':'fabulous'}
dict.update(dict1)

# by assigning
dict.update(newkey1 ='portal')
print(dict)

Output:

Current Dict is: {‘key2’: ‘for’, ‘key1’: ‘geeks’}
{‘newkey1’: ‘portal’, ‘key4’: ‘is’, ‘key2’: ‘for’, ‘key1’: ‘geeks’, ‘key5’: ‘fabulous’, ‘key3’: ‘geeks’}

Code #3: Taking Key:value as input

# Let's add key:value to a dictionary, the functional way

# Create your dictionary class
class my_dictionary(dict):

    # __init__ function
    def __init__(self):
        self = dict()

    # Function to add key:value
    def add(self, key, value):
        self[key] = value

# Main Function
dict_obj = my_dictionary()

# Taking input key = 1, value = Geek
dict_obj.key = input("Enter the key: ")
dict_obj.value = input("Enter the value: ")

dict_obj.add(dict_obj.key, dict_obj.value)
dict_obj.add(2, 'forGeeks')

print(dict_obj)

Output:

 {'1': 'Geeks', 2: 'forGeeks'}