For Loop in Ruby

In this tutorial, we will learn about for loops in Ruby. We will cover the basics of iterative execution using for loops.

What is a For Loop

In Ruby, a for loop is used to iterate over a collection of items, and execute a block of code for each element in the collection.

Syntax

The syntax for the for loop in Ruby is:

for item in iterable do
    # Code block to be executed
end

The for loop iterates over each item in the iterable object (such as an array or a range) and executes the code block for each item. We can access the item inside the for loop.


Example 1: Printing Numbers from 1 to 10

We can use a For loop to iterate over a range of numbers.

For example,

  1. Write a For loop that iterates over a range of numbers: 1 to 10.
  2. Inside the For loop, print the number to output.

Ruby Program

for i in 1..10
    print i, " "
end

Output

1 2 3 4 5 6 7 8 9 10

Example 2: Calculating the Factorial of a Number

We have seen how to use a For loop to iterate over a range of numbers. using this we can find the factorial of a number, by iterating the for loop from 1 to the given number.

For example,

  1. Use a for loop to calculate the factorial of a number.

Ruby Program

n = 5
factorial = 1
for i in 1..n
    factorial *= i
end
puts "Factorial of #{n} is #{factorial}"

Output

Factorial of 5 is 120

Example 3: Summing the Elements of an Array

We have seen how to use a For loop to iterate over a range of numbers. using this we can accumulate the numbers in a sum, by iterating the for loop from 1 to the given number.

For example,

  1. Use a for loop to calculate the sum of the elements in an array.

Ruby Program

arr = [1, 2, 3, 4, 5]
sum = 0
for num in arr
    sum += num
end
puts "Sum of the elements in the array is #{sum}"

Output

Sum of the elements in the array is 15