Dictionaries in Python: A Complete Tutorial with Code Examples

Dictionaries in Python are essential data structures that allow for the storage and manipulation of data in key-value pairs. A range of numbers indexes lists, while keys index dictionaries. Which can be any immutable type. This makes dictionaries incredibly powerful and flexible for various programming tasks.

In this tutorial, we will explore the various aspects of dictionaries in Python, from their characteristics and creation to accessing and updating built-in functions and methods. After reading this article, you will understand how to effectively use dictionaries in your Python programs.

What is a Dictionary in Python?

In Python, a dictionary is a mutable, unordered collection of items where each item is stored in a key-value pair. Dictionaries are commonly used to store data in a way that allows quick access and modification. Here’s a brief overview of dictionaries in Python language.

Characteristics of Python Dictionaries 

• Key-Value Pairs: In the Dictionary, each item is a pair consisting of a key and a value. Keys must be unique and immutable(e.g., strings, numbers, or tuples), while values of any data type can be duplicated.

• Unordered: Python dictionaries are unordered collections, which means that items do not have a defined order and cannot be accessed by an index.

• Mutable: Dictionaries are mutable, meaning you can add, remove or change items after creating the dictionary.

Creating a Python dictionary is very simple. The required key and value pairs are within curly brackets and separated by the key-value pair.

The following program creates a dictionary in Python language.

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Accessing values in Python Dictionary

In Python, we can access the dictionary items using the square brackets that are also commonly used for indexing and slicing strings in Python).

The following program access time from the dictionary in Python language

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Updating Dictionary in Python

We can also update the dictionary in Python language in Python. We can add a new entry or modify the existing entry and add multiple values to a single key.

The following program demonstrates updating the dictionary values in Python.

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Deleting Dictionary Elements

We can also delete the dictionaries in Python language. Let’s look at “ how we can either delete the dictionary entirely or remove individual entries”.

To remove an entire dictionary. We can use the ‘del’ keyword in Python language.

The following program demonstrates “del keyword in Python”.

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We can also clear the whole dictionary using the clear()method.

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Iterating Dictionary in Python

You can iterate through a dictionary’s keys, values, or key-value pairs in Python language.

The following program Iterate the dictionary using the loop.

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Properties of Python Dictionary Keys

Let’s see the properties of Python dictionary kes summarized in single points.

• Immutability: Python dictionary must be immutable.
• Uniqueness: Python keys within a dictionary must be unique
• Hashability: Python keys must be hashable.
• Comparable: Python keys must support equality comparison

Built-in Python Dictionary Functions & Methods

There are some built-in methods and functions in Python.

Conclusion

In this article, we learned about the dictionaries in Python. It is a versatile and powerful data structure tool that efficiently stores and manages data using key-value pairs. It offers several advantages, such as fast lookups, flexibility in data types for keys and values, and ease of use with various built-in methods. Mastering Python dictionaries enhances your capability to handle data efficiently, perform rapid searches, and develop sophisticated applications. There are also some built-in methods and functionalities, such as ‘get()’, ‘update()’, ‘items()’, ‘keys()’ and values()’.