Learn Ruby – How To Convert a String to Lower or Uppercase?

In Ruby, a String contains and manipulates an arbitrary sequence of bytes, typically representing characters. When you want to change the contents of a String in Ruby, it should be noted that methods with the name ending in “!” modify the String that is receiving this method, while those without “!” return a new String.

How to convert a string to Lower or Uppercase of a String in Ruby

To convert the content to lowercase, use .downcase:

Similarly, to transform everything to uppercase, use .upcase:

If you want to capitalize only the first letter of a String, use the .capitalize method:

You can also use .titleize to ensure that the first letter of each word in the String will be uppercase:

Remember that if you add the exclamation point in any of these methods, the original String will be modified, as shown below:


Including support for Unicode, and ASCII in capitalization methods in Ruby

These methods operate natively in ASCII. To add support for Unicode, is necessary to install a gem, as showed below:

Do you know other ways to perform this case changes on a String in Ruby? Share your comments in the section below!

If you want to explore other questions about this programming language, you can check out our Ruby programming videos about Ruby. Below we show some examples:


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Ruby string uppercase lowercase capitalize programming j-mcnally



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Another cool way to find out interesting things about Ruby is to access our project page!

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  • Max

    Cool. Thank you!

  • Nitish Singh

    Great tutorial. I like how it layed out. Wonderful work.

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