Python Dictionary and its operations

Hello everyone, Welcome back to proramminginpython.com. Here in this post am going to introduce you to one of the popular Python data types Dictionary. Lists and Tuples are some of the other data types. Dictionaries are indexed by keys and can be of any immutable type. These are unordered key-value pairs with unique keys.

A dictionary can be created simply by writing curly braces {}an example dictionary will look like {'key1': 'value1', 'key2': 'value2'}

Now lets go through the operations that can be performed on dictionaries.

You can also watch the video on YouTube here

Program on GitHub

Create Dictionary

I will create a dictionary named my_infoand add some key-value pairs to it.

# add elements to dictionary
my_info = {
    'Name': 'Avinash',
    'Age': 23,
    'Gender': 'Male',
    'Location': 'India',
    'Website': 'programminginpython.com'
    }

and print it.

# print dictionary
print(my_info)

Program on GitHub

Accessing Values

Now I can access the elements in the dictionary by their key, here I will print the value of the key 'Name'.

my_info = {
    'Name': 'Avinash',
    'Age': 23,
    'Gender': 'Male',
    'Location': 'India',
    'Website': 'programminginpython.com'
    }

# print value of a key
print(my_info['Name'])

[Python Dictionary and its operations]Python Dictionary and its operations

Modifying values

I can also modify the existing elements in the dictionary, here I will modify the value of key 'Age'

my_info = {
    'Name': 'Avinash',
    'Age': 23,
    'Gender': 'Male',
    'Location': 'India',
    'Website': 'programminginpython.com'
    }

# modify elements in dictionary
my_info['Age'] = 24
print(my_info)

[Python Dictionary and its operations]Python Dictionary and its operations

Program on GitHub

Length of dictionary

I can also find the length of the dictionary, using the built-in method len() which gives the total number of items in the dictionary.

my_info = {
    'Name': 'Avinash',
    'Age': 23,
    'Gender': 'Male',
    'Location': 'India',
    'Website': 'programminginpython.com'
    }

# length of dictionary
print(len(my_info))

[Python Dictionary and its operations]Python Dictionary and its operations

Delete elements

I can also delete a particular key from a dictionary, here I will delete key 'Website'

my_info = {
    'Name': 'Avinash',
    'Age': 23,
    'Gender': 'Male',
    'Location': 'India',
    'Website': 'programminginpython.com'
    }

# delete a particular key 
del my_info['Website'] 
print(my_info)

Similarly, I can remove all the elements using a function called clear() which empties all the elements in the dictionary

# removes all elements in dictionary 
my_info.clear()

I can also delete the entire dictionary,

# delete entire dictionary 
del my_info

These are some of the operations that can be performed on dictionaries.

Program on GitHub

The complete code for the above snippets,

__author__ = 'Avinash'

# add elements to dictionary
my_info = {
    'Name': 'Avinash',
    'Age': 23,
    'Gender': 'Male',
    'Location': 'India',
    'Website': 'programminginpython.com'
    }

# print dictionary
print(my_info)

# print value of a key
print(my_info['Name'])

# modify elements in dictionary
my_info['Age'] = 24
print(my_info)

# length of dictionary
print(len(my_info))

# delete a particular key
del my_info['Website']
print(my_info)

# removes all elements in dictionary
my_info.clear()
print(my_info)

# delete entire dictionary
del my_info