When to Use a List Comprehension in Python

by Abdul Rawoof A R Updated: Jan 31, 2023

Guide Kit

List comprehension is a straightforward method to create a new list in Python. It consists of an expression followed by at least one "for" clause and zero or more "if" clauses. The expression is evaluated for each item in the input iterable(s) that pass the if clause(s), and the results are collected in a new list.

for: In Python, a for the clause is used in a list comprehension, and other constructs, such as for loops, to iterate over the elements of an iterable. You can also use multiple for clauses in a list comprehension or a for loop to iterate over multiple iterable.
if: The if statement in Python is used to modify the course of a program's execution depending on one or more criteria. It is used to check whether a specific condition is true or false and, if it is, to run a block of code.

List comprehensions are generally used in transforming or filtering elements of an existing list or creating a new list based on multiple existing lists.

You may have a look at the code given below for list comprehension in Python.

Fig : Preview of the output that you will get on running this code from your IDE.

Code

List comprehension

PythonLines of Code : 10License : Strong Copyleft (CC BY-SA 4.0)

weekly_moods = [mood_options[score-1] for score in weekly_scores]

mood_options = ["awful", "bad", "meh", "good", "amazing"]
weekly_scores = [2, 4, 1, 3, 4, 2, 4]

weekly_moods = [mood_options[score - 1] for score in weekly_scores]
print(weekly_moods)

['bad', 'good', 'awful', 'meh', 'good', 'bad', 'good']

Instructions

Follow the steps carefully to get the output easily.

Install python on your IDE(Any of your favorite IDE).
Copy the snippet using the 'copy' and paste it in your IDE.
Run the file to generate the output.

I hope you found this useful.

I found this code snippet by searching for 'List comprehension in python' in kandi. You can try any such use case!

Environment Tested

I tested this solution in the following versions. Be mindful of changes when working with other versions.

The solution is created in PyCharm 2021.3.
The solution is tested on Python 3.9.7.

Using this solution, we are able to list comprehension in python with simple steps. This process also facilities an easy way to use, hassle-free method to create a hands-on working version of code which would help us to list comprehension in python.

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