For Loop with Ranges

Part of the Fundamentals section of Coddy's Ruby journey — lesson 39 of 88.

Loops let you repeat code multiple times without writing it over and over. In Ruby, the for loop combined with a range is a straightforward way to iterate through a sequence of numbers.

A range in Ruby represents a sequence of values. You create one using two dots between a start and end value. Here's how to loop through numbers 1 to 5:

for i in 1..5
  puts i
end

This outputs each number from 1 to 5, each on its own line. The variable i takes on each value in the range, one at a time, and the code inside the loop runs for each value.

Ruby has two types of ranges. The two-dot range 1..5 includes both endpoints (1, 2, 3, 4, 5). The three-dot range 1...5 excludes the last number (1, 2, 3, 4):

for num in 1...4
  puts num
end
# Outputs: 1, 2, 3

You can use any variable name you like and perform operations inside the loop. For example, printing the square of each number:

for n in 1..3
  puts n * n
end
# Outputs: 1, 4, 9

Challenge

Easy

Read a number n from input. Use a for loop with a range to print all numbers from 1 to n, each on its own line.

The input will be a single integer representing the upper limit of the range.

For example, if the input is 4, the output should be:

Cheat sheet

The for loop with a range allows you to iterate through a sequence of numbers:

for i in 1..5
  puts i
end

Ruby has two types of ranges:

1..5 - includes both endpoints (1, 2, 3, 4, 5)
1...5 - excludes the last number (1, 2, 3, 4)

for num in 1...4
  puts num
end
# Outputs: 1, 2, 3

You can use any variable name and perform operations inside the loop:

for n in 1..3
  puts n * n
end
# Outputs: 1, 4, 9

Try it yourself

# Read the number from input
n = gets.to_i

# TODO: Write your code below
# Use a for loop with a range to print all numbers from 1 to n

Test yourself

This lesson includes a short quiz. Start the lesson to answer it and track your progress.

All lessons in Fundamentals

1Introduction to Ruby

What is Ruby?Hello World Comments in Ruby

4Operators Part 2

Logical Operators Part 1 Logical Operators Part 2 Recap - Simple Logic Logical Operators Part 3 Logical Operators Part 4

7Bill Split Calculator

Welcome Message Getting User Input

Calculating Tip And Total

Splitting The Bill

Formatted Output

10FizzBuzz with a Twist

Game Overview The FizzBuzz Method

Looping Through Numbers

Adding The Twist

13Arrays Advanced

Array Slicing with Ranges Array Slicing with Indexes Array Operators Include? Method

16Final Challenges

Flat Asterisk Pyramid Pattern Finder What To Buy