Difference Between Set and Dictionary in Python

Sets vs. Dictionaries in Python: Unravel the nuances of these two dynamic data structures, from uniqueness to data storage, and optimize your Python programming.

Python offers several built-in data structures like tuples, sets, and dictionaries. These data structures help to store and organize data efficiently. This article will briefly discuss the difference between two such data structures, a set and a dictionary.

So, without further delay, let’s start the article.

Must Check: Top Python Online Courses and Certifications

Table of Contents

• Difference Between Set and Dictionary in Python
• What is Set in Python?
  • Operations on Set
  • Key Features of Set
  • Application of Set
• What is Dictionary in Python
  • Operations on Dictionary
  • Key Features of Dictionary
  • Application of Dictionary
• Key Difference Between Set and Dictionary in Python

Difference Between Set and Dictionary in Python: Set vs Dictionary

Parameter	Set	Dictionary
Definition	An unordered collection of unique elements.	An ordered collection of key-value pairs.
Representation	Curly braces {}.	Curly braces {}, but with key-value pairs.
Order	Unordered.	Ordered (from Python 3.7 onwards).
Duplicates	Does not allow duplicate elements.	Does not allow duplicate keys.
Mutability	Mutable (can add or remove elements).	Mutable (can add, modify, or remove key-value pairs).
Access Method	Elements are accessed directly.	Values are accessed using keys.
Use Case	To store unique elements.	To store related pieces of information.
Example	my_set = {1, 2, 3}	my_dict = {“name”: “Alice”, “age”: 30}

What is Set in Python?

A set in Python is an unordered collection of unique elements. Think of it as a bag where you can throw in items, but each item can exist only once. But if you try to add a duplicate, python will simply ignore it. This characteristic of the set makes it extremely useful for tasks like eliminating duplicate entries from a list or checking the membership of an element in a collection.

Now, let’s have an example of sets in Python.

Output

Must Read: Python Practice Set for Beginners

Find out about top job-oriented courses available after 12th. Also, explore specialized online degree programs for a amazing career path.

Operation Performed on Sets

• add(): Add an element to the set.
• remove(): Remove an element from the set.
• discard(): Remove an element from the set, but only if it is present.
• clear(): Remove all elements from the set.
• union(): Return a new set containing the union of two sets’ elements.
• intersection(): Return a new set containing the intersection of two sets’ elements.
• difference(): Return a new set that contains the difference of the elements of two sets.
• issubset(): Return True if the first set is a subset of the second set; otherwise, return False.
• issuperset(): Return True if the first set is a superset of the second set; otherwise, return False.

Key Features of Set in Python

• Unordered: The elements in the set are unordered, i.e., elements are not in a specific order.
• Mutable: You can add or delete elements from a set.
• No Duplicate: Sets automatically remove duplicate elements.
• Representation: Represented by curly ({}) braces.

Application of Sets in Python

• Web scraping: Sets can be used to remove duplicate elements from a list of URLs to scrape or to find the unique elements in a list of scraped data.
• Natural language processing (NLP): Sets can be used to remove stop words from a text corpus or to find the unique words in a text document.
• Machine learning: Sets can be used to represent features in a machine learning dataset or to find the unique values of a target variable.
• Data analysis: Sets can group data into categories or find a variable’s unique values.

What is a Dictionary in Python?

A dictionary in Python is an ordered collection of key-value pairs. Imagine a real-life dictionary where you look up a word (the key) to find its definition (the value). Similarly, you use a key in a Python dictionary to retrieve its corresponding value.

Similar to sets in Python, dictionaries are also mutable, meaning that you can add, remove, or change their key-value pairs. In Python, dictionaries are created using the dict() function.

Now, let’s have a simple example:

Output

Must Read: Python Dictionary Practice Program for Beginners

Operations Performed on Dictionaries

• get(): Get the value associated with a key. The default value is returned if the key is not present in the dictionary.
• items(): Return a list of key-value pairs in the dictionary.
• keys(): Return a list of keys in the dictionary.
• values(): Return a list of values in the dictionary.
• update(): Update the dictionary with a new set of key-value pairs.
• clear(): Remove all key-value pairs from the dictionary.

Key Features of Dictionaries

• Key-Value Pairs: Each entry in a dictionary consists of a key and its associated value.
• Ordered: Since Python 3.7, dictionaries maintain the order of insertion.
• Mutable: You can modify a dictionary by adding or removing key-value pairs after its creation.
• Unique Keys: While values can be duplicated, each key in a dictionary must be unique.
• Representation: Dictionaries also use curly braces {} but with key-value pairs.

Application of Dictionary

• Data storage: Dictionaries can store data in a structured way, making it easy to access and manage. For example, you could use a dictionary to store the contact information for your customers or employees.
• Configuration files: Dictionaries can be used to create configuration files that store settings for your application. This can be useful for storing database connection settings, API keys, or user preferences.
• Caching: Dictionaries can be used to implement caching, which can improve the performance of your application by storing frequently accessed data in memory.
• Data Analysis: Dictionaries can analyze data by grouping it into categories or counting the occurrences of different values. For example, you could use a dictionary to count the number of times each word appears in a text document.
• Web Development: Dictionaries are commonly used to store data about users, sessions, and other aspects of the web application.

Key Differences and Similarities Between Set and Dictionary in Python

• Sets are an unordered collection of unique elements, whereas a dictionary is an ordered collection of key-value pairs.
• Sets store unique elements, while dictionaries store related pieces of information.
• Elements of both sets and dictionaries are mutable.
• Both sets and dictionaries do not allow duplicate entries.