1. Introduction to List Comprehension

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List comprehension is a concise way to create lists in Python. Instead of using loops and append(), you can generate lists in a single line of code.

Why use list comprehension?

List comprehension is preferred over traditional loops for three main reasons:

• Conciseness – It reduces the number of lines of code.
• Readability – The logic is easier to understand at a glance.
• Performance – It runs faster than using a for loop with append().

Basic syntax

[expression for item in iterable]

• expression → The operation you want to perform on each item.
• for item in iterable → Loops through each element in the iterable (like a list or range).

Example: Creating a list of squares

Let's create a list of squares from 1 to 10 using list comprehension.

Using a Traditional Loop

squares = []
for num in range(1, 11):
    squares.append(num ** 2)
print(squares)  # Output: [1, 4, 9, 16, 25, 36, 49, 64, 81, 100]

Using list comprehension

squares = [num ** 2 for num in range(1, 11)]
print(squares)  # Output: [1, 4, 9, 16, 25, 36, 49, 64, 81, 100]

Key differences

Approach	Code Length	Readability	Performance
Traditional Loop	Longer	Requires more steps	Slower
List Comprehension	Shorter	More intuitive	Faster