While and Until in Ruby

While Loop

In the While loop, the test condition is specified at the start of the loop, and all statements are run until the boolean condition is satisfied. The control will exit the while loop when the condition turns false. Because the condition to be tested is present at the beginning of the loop body, it is also known as an Entry Controlled Loop. Generally, a while loop is used when the number of iterations in a program is not fixed.

Syntax:

while conditional [do]

 # code to be executed

end

You can also try this code with Online Ruby Compiler

Run Code

Let’s see the working of the while loop with the help of a Code Example.

# Ruby program to see the working of 'while' loop

# variable count
count = 5

# using while loop
# here conditional is count i.e. 5
while count >= 1

# statements to be executed
puts "Coding Ninjas"
count = count - 1

# while loop ends here
end

You can also try this code with Online Ruby Compiler

Run Code

Output:

Since we have run the While loop for count=5 number of times, it prints the Coding Ninjas five times.

Until Loop

The statements or code in a Ruby Until loop are executed till the provided condition evaluates to true. It's basically the opposite of the while loop, which runs until the specified condition evaluates to false. The conditional in an until the statement is separated from the code by the reserved word do, a new line, or a semicolon.

Syntax:

until conditional [do]

 # code to be executed

end

You can also try this code with Online Ruby Compiler

Run Code

Let’s see the working of until loop with the help of a Code Example.

# Ruby program to see the working of 'until' loop

count = 10

# using until loop
# here do is optional
until count==5 do

# code to be executed
puts "Coding Ninjas"
count = count - 1

# here loop ends
end

You can also try this code with Online Ruby Compiler

Run Code

Output:

Since we have run the Until loop till the count is equal to 5, and we started with count=10, it will execute a total of 5 number of times the statement inside the Until loop; therefore, it prints the Coding Ninjas five times.

Frequently Asked Questions

What are Objects in Ruby?

In Ruby, everything is an object. All objects have a unique identification; they can also maintain a state and exhibit behavior in response to messages. Usually, these messages are sent out via method calls. A string is an example of a Ruby object.

What is Looping in Ruby?

In Ruby, looping is a feature that allows a sequence of instructions or functions to be executed repeatedly when some of the conditions evaluate true or false.

What are the main types of loops provided by Ruby?

There are mainly four loops in Ruby:-

1.) While Loop

2.) For Loop

3.) Do-While Loop

4.) Until Loop

How does the While loop work in Ruby?

In the While loop, the test condition is specified at the start of the loop, and all statements are run until the boolean condition is satisfied. The control will exit the while loop when the condition turns false.

How does the Until loop work in Ruby?

The statements or code in a Ruby Until loop are executed till the provided condition evaluates to true. It's basically the opposite of the while loop, which runs until the specified condition evaluates to false.

Conclusion

In this article, we have extensively discussed Looping in Ruby and how the while and until loop works in Ruby with the help of code examples.

After reading about the While and Until in Ruby, are you not feeling excited to read/explore more articles on the topic of Ruby? Don't worry; Coding Ninjas has you covered. To learn, see Object Marshalling in Ruby, Tainting Objects in Ruby, Copying Objects In Ruby, How To Invoke Global Functions In Ruby?, and Object References in Ruby.

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