Ruby Loops

Loops are used to execute the same block of code a certain number of times. This post details main the loop statements used in Ruby.

How do we build a loop, that executes exactly 5 times?

In the first step, we need to set a counter.

  counter = 0    #  It starts our counter at 0

Then we increment our counter by 1 and set it equal to the sum of its current value, plus 1

loop do
   counter = counter + 1

Put the code to be executed

puts "I love Ruby #{counter}!"

In the last step, we should conditionally break out of the loop when the counter reaches 5.

if counter >= 5 # If our counter is 5 or more
    break # Stop the loop
  end
end

Final code

counter = 0
loop do 
   
  
   counter = counter + 1

   puts "I love Ruby #{counter}!"

    if counter >= 5 
    break 
    end
 end

If you paste this to IRB it will print out:

I love Ruby 1!
I love Ruby 2!
I love Ruby 3!
I love Ruby 4!
I love Ruby 5!

TIMES METHOD LOOP

The “times” method is called on an Integer (5 or 99) and executes the block a certain number of times (the number that it's called on).

Please the example below:

4.times do
puts "I am time method"
end
--------
Irb output -
"I am times method"
"I am times method"
"I am times method"
"I am times method"

“while” loop

As its name suggests the while will keep executing a block as long as a specific condition is met or true.

Let’s look at an example below

num_of_beers_drinked = 0
# => 0 (return value)

while num_of_beers_drinked < 4
  num_of_beers_drinked += 1
  puts "I have now drinked #{num_of_beers_drinked} beer(s)."
end
# => nil (return value)

puts "You drunk a total of #{num_of_beers_drinked} beers!"
# => nil (return value)
Output:
# > "I have now drinked 1 beer(s)."
# > "I have now drinked 2 beer(s)."
# > "I have now drinked 3 beer(s)."
# > "I have now drinked 4 beer(s)."
# > "You drunk a total of 4 beers!"

“UNTIL” loop

until is simply the opposite of a while loop. The block of code following until will execute while the condition is false.

See the example below:

def party
  num_of_beers_drinked = 0
  until num_of_beers_drinked == 4
  puts 'You are good boy'
  num_of_beers_drinked += 1
  end
end

when we invoke the “party” function it returns:

'You are good boy'
'You are good boy'
'You are good boy'
'You are good boy'