Dictionaries in Python

This tutorial explores dictionaries in Python, a powerful and versatile data structure used to store and manipulate data through key-value pairs. The tutorial explains the basics of dictionaries, how to create and modify them, and provides examples of their various use cases.

Updated March 8, 2023

Hello future Python wizard, welcome to Python Help! Welcome to another thrilling tutorial on the world of Python programming.

Today, we’ll be discussing dictionaries in Python, one of the most powerful and versatile data structures in the language.

Dictionaries are an unordered collection of key-value pairs. They are similar to lists and tuples in that they are used to store and manipulate data, but they differ in their structure and usage. In a dictionary, each key-value pair is separated by a colon and enclosed in curly braces.

To create a dictionary in Python, simply list the key-value pairs inside the curly braces, like so:

my_dict = {"key1": "value1", "key2": "value2", "key3": "value3"}

In this example, we’ve created a dictionary with three key-value pairs. The keys are “key1”, “key2”, and “key3”, and the values are “value1”, “value2”, and “value3”, respectively.

One of the most useful features of dictionaries is their ability to store and retrieve data quickly and efficiently. In fact, dictionaries are often used as lookup tables or mapping structures in programming.

To retrieve the value associated with a particular key in a dictionary, simply use the key as an index, like so:

print(my_dict["key2"])  # Output: "value2"

In this example, we’ve retrieved the value associated with the “key2” key in the dictionary.

Dictionaries can also be modified after they are created. To add a new key-value pair to a dictionary, simply assign a value to a new key:

my_dict["key4"] = "value4"

In this example, we’ve added a new key-value pair to the dictionary. The new key is “key4”, and the value is “value4”.

Dictionaries can also be used in conjunction with loops and other control structures to perform powerful and complex operations.

For example, we can use a for loop to iterate over all the key-value pairs in a dictionary:

for key, value in my_dict.items():
    print(key, value)

n this example, we’ve used the items() method to retrieve a list of all the key-value pairs in the dictionary. We’ve then used a for loop to iterate over each key-value pair and print it out.

Finally, it’s worth noting that dictionaries can be used to store a wide variety of data types, including lists, tuples, and even other dictionaries. This allows for a high degree of flexibility and customization when working with data in Python.


Dictionaries are a powerful and versatile data structure in Python. They allow for fast and efficient storage and retrieval of data, and they can be used in conjunction with loops and other control structures to perform complex operations. I hope this article has helped you understand dictionaries a little better, and I encourage you to explore the many ways in which you can use them in your own Python programming.

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