Simple squaring
Input
square_each([1, 2, 3])
Output
[1, 4, 9]
Each element is squared: 1->1, 2->4, 3->9.
Full lesson preview
Square Each Number
Return a list where each number from the input has been squared.
Python practice10 minLoops & IterationBeginnerLast updated March 15, 2026
Problem statement
Write a function square_each(nums) that takes a list of integers nums and returns a new list where each integer is replaced by its square (n * n). Preserve the order. For an empty input list, return an empty list.
Task
Practice transforming list elements using loops and returning a new list.
Examples
Input format
A single list of integers, e.g. [1, -2, 3].
Output format
A list of integers representing squares of the inputs, e.g. [1, 4, 9].
Constraints
Do not use list comprehensions for beginners who have not learned them yet; use an explicit loop. Aim for O(n) time.
Samples
Sample 1
Input
square_each([-1, 0, 5])
Output
[1, 0, 25]
Squares: (-1)^2=1, 0^2=0, 5^2=25.