Loops and .each

So far, every line of your code has run exactly once. But what if you want to repeat an action many times, like printing every item in a list? That is exactly what loops are for.

The times loop

The simplest loop in Ruby repeats a block of code a set number of times using .times.

3.times do
  puts "Hello!"
end

This prints "Hello!" three times in a row. The word do starts the block of repeated code, and end finishes it.

Looping over an array with .each

The most common loop in Ruby is .each, which runs a block of code once for every item in an array.

fruits = ["apple", "banana", "cherry"]
fruits.each do |fruit|
  puts "I like #{fruit}."
end

This prints "I like apple.", "I like banana.", and "I like cherry." The word between the vertical bars, fruit, is a temporary variable that holds the current item during each pass through the loop. You can name it anything you like.

Looping over a hash

You can loop over a hash too, and Ruby gives you both the key and the value on each pass.

person = { name: "Ava", age: 12 }
person.each do |key, value|
  puts "#{key}: #{value}"
end

This prints "name: Ava" and then "age: 12".

Loops let your programs handle lists of any size, whether they hold three items or three million, without writing the same line of code over and over.