Dictionary in Python
In Python, a dictionary is a built-in data structure that allows you to store key-value pairs. It is also known as a hash table or associative array. In this blog, we will explore how dictionaries work in Python, and how you can use them in your programs.
Creating a Dictionary
To create a dictionary in Python, you can use curly braces {} or the dict() constructor function. Here's an example:
# Using curly braces
my_dict = {'name': 'John', 'age': 30, 'city': 'New York'}
# Using dict() constructor
my_dict = dict(name='John', age=30, city='New York')
In the above code, we have created a dictionary with three key-value pairs, where the keys are name, age, and city, and the values are John, 30, and New York, respectively.
Accessing Dictionary Elements
To access a value in a dictionary, you can use the key inside square brackets or the get() method. Here's an example:
my_dict = {'name': 'John', 'age': 30, 'city': 'New York'}
# Accessing value using key
print(my_dict['name']) # Output: John
# Accessing value using get()
print(my_dict.get('age')) # Output: 30
In the above code, we have accessed the values of the name and age keys using both square brackets and the get() method.
Updating a Dictionary
To update the value of a key in a dictionary, you can simply assign a new value to it. Here's an example:
my_dict = {'name': 'John', 'age': 30, 'city': 'New York'}
# Updating value of a key
my_dict['age'] = 31
print(my_dict) # Output: {'name': 'John', 'age': 31, 'city': 'New York'}
In the above code, we have updated the value of the age key to 31.
Adding a New Key-Value Pair
To add a new key-value pair to a dictionary, you can simply assign a value to a new key that doesn't exist in the dictionary. Here's an example:
my_dict = {'name': 'John', 'age': 30, 'city': 'New York'}
# Adding a new key-value pair
my_dict['country'] = 'USA'
print(my_dict) # Output: {'name': 'John', 'age': 30, 'city': 'New York', 'country': 'USA'}
In the above code, we have added a new key-value pair, where the key is country and the value is USA.
Removing a Key-Value Pair
To remove a key-value pair from a dictionary, you can use the del keyword or the pop() method. Here's an example:
my_dict = {'name': 'John', 'age': 30, 'city': 'New York'}
# Removing a key-value pair using del keyword
del my_dict['city']
print(my_dict) # Output: {'name': 'John', 'age': 30}
# Removing a key-value pair using pop() method
age = my_dict.pop('age')
print(my_dict) # Output: {'name': 'John'}
print(age) # Output: 30
In the above code, we have removed the city key-value pair using the del keyword, and the age key-value pair using the pop() method.
( Please click on above link for iterating through a dictionary python )
Happy Learning!! Happy Coding!!
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