Regular expressions or regex is a sequence of characters which specifies a search pattern. They are essentially a matching pattern that allows you to search for specific patterns in text. In Ruby, we can use the "regex" module which is part of the core library for Ruby.
Here are a few examples of how you can use regex in Ruby:
1. Basic Matching:
string = "The quick brown fox jumps over the lazy dog"
if string =~ /quick/
puts "It matches the word quick"
else
puts "It doesn't match"
end
2. Multiline Matching:
string = "apple
banana
orange"
if string =~ /banana/
puts "It matches the word banana"
else
puts "It doesn't match"
end
3. Using the match method:
string = "The quick brown fox jumps over the lazy dog"
match = string.match(/jumps/)
puts match[0]
#output: jumps
4. Replacing strings:
string = "The quick brown fox jumps over the lazy dog"
string.gsub!(/quick/, "slow")
puts string
#output: "The slow brown fox jumps over the lazy dog"
These are just a few examples of how you can use regex in Ruby. Regex is a very powerful tool when working with text and can help you find, validate, and replace text in a very efficient way.