Reversing a String and Checking for Palindromes

In this lesson you will learn to reverse a string with Ruby's reverse method and check for palindromes. This is for anyone searching for "Ruby reverse string".

.reverse reverses a string. A string that reads the same forwards and backwards is called a palindrome. Being able to call reverse straight on a string, without first breaking it into an array as some languages require, is a real convenience.

The sample code compares the original with its reverse in the single line str == str.reverse inside the palindrome? method. "racecar" comes out the same either way, so it is reported as a palindrome.

A common stumbling block for beginners coming from a language such as JavaScript is assuming they must convert the string to an array first. Ruby string handling is designed to cope naturally with multi-byte characters too, so calling reverse directly is enough.

Treating a string as a sequence of characters applies broadly to other text processing. Palindrome checking is a classic exercise that shows off just how easy Ruby makes this.

📖 Reference code

def palindrome?(str)
  str == str.reverse
end

puts palindrome?("racecar")
puts palindrome?("hello")

✍️ Your code

Type your code, then press "Run"

🧪 This site can't compile or run Ruby directly, so it checks on the spot whether what you typed matches the reference code (scoring happens entirely in your browser — nothing is sent anywhere).