How to Use the Ruby extname Method

In this article, you will learn how to use the Ruby extname method.

Using the extname method

The Ruby extname method is used to extract the extension of a file name. It returns the extension, including the period (.), of a file name as a string. Here’s how to use the extname method in Ruby:

Call the extname method on a file name string:

filename = "example.txt"
extension = File.extname(filename)

The extname method will return the extension of the file name as a string:

puts extension # => ".txt"

If the file name does not have an extension, the extname method will return an empty string:

filename = "example"
extension = File.extname(filename)
puts extension # => ""

If the file name has multiple extensions, the extname method will return the last extension:

filename = "example.tar.gz"
extension = File.extname(filename)
puts extension # => ".gz"

The extname method can also be used with file paths:

filepath = "/home/user/example.txt"
extension = File.extname(filepath)
puts extension # => ".txt"

The extname method is case-sensitive and will return the extension as it appears in the file name or path:

filename = "example.TXT"
extension = File.extname(filename)
puts extension # => ".TXT"

It’s important to note that the extname method only returns the extension of a file name or path and does not validate whether the file actually exists or not:

filename = "nonexistent_file.txt"
extension = File.extname(filename)
puts extension # => ".txt"