Checking Whether a String Contains a Substring

In Ruby, you can easily determine if a string contains a specific substring using built-in methods.

Using the include? Method

What is include?

The include? method is a simple way to check if a substring exists within a string. It returns true if the substring is found and false otherwise.

Syntax of include?

string.include?(substring)

Here, string is the original string you want to search in, and substring is the string you want to check for.

Example

sentence = "The quick brown fox jumps over the lazy dog."

puts sentence.include?("fox")     # Output: true
puts sentence.include?("cat")     # Output: false

In this example, the include? method is used to check if the substring "fox" and "cat" exist within the sentence. The first check returns true, while the second check returns false.

Using the match Method with Regular Expression

What is match?

The match method allows you to search for a substring using regular expressions. It returns a MatchData object if a match is found or nil if no match is found.

Syntax of match

result = string.match(/regex/)

Here, string is the original string you want to search in, and /regex/ is the regular expression pattern for the substring you want to find.

Example

sentence = "The quick brown fox jumps over the lazy dog."

result = sentence.match(/fox/)
puts result                      # Output: #<MatchData "fox">

In this example, the match method is used with the regular expression /fox/ to find the substring "fox" within the sentence. The method returns a MatchData object containing the matched substring.