Add a key:value pair to dictionary in Python

Last Updated : 14 Jan, 2019

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'}

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