Loops and Iterators

Loops allow your Ruby programs to repeat actions efficiently.

In this lesson, you will learn how to use loops like while, until, for, and iterators like each.

Using While Loop

The while loop repeats a block of code while a condition is true.

count = 1
while count <= 5
  puts count
  count += 1
end

Using Until Loop

The until loop runs until the condition becomes true.

count = 1
until count > 5
  puts count
  count += 1
end

Using For Loop

The for loop is useful for iterating over a range.

for i in 1..5
  puts i
end

Using Each Method

The each method iterates over an array or range.

[1, 2, 3, 4, 5].each do |num|
  puts num
end

Using Loop Statement

The loop method runs indefinitely unless stopped.

i = 1
loop do
  puts i
  i += 1
  break if i > 5
end

Break and Next in Loops

break exits a loop, and next skips to the next iteration.

for i in 1..5
  next if i == 3
  break if i == 5
  puts i
end

Using Map for Transformation

The map method transforms each element in a collection.

numbers = [1, 2, 3, 4, 5]
squares = numbers.map { |n| n * n }
puts squares

Congratulations!

You have learned different types of loops and iterators in Ruby.

Next, you will learn about logical and comparison operators.