How to Use the Ruby match Method

09/23/2021

Contents

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

Using the match method

The match method in Ruby is a powerful method that allows you to search for a specific pattern within a string and extract any matching portions of the string.

The basic syntax for the match method is as follows:

string.match(pattern)

Here, string is the string you want to search, and pattern is the regular expression pattern you want to match against the string.

For example, let’s say we have a string str = “The quick brown fox jumps over the lazy dog.”, and we want to search for the word “brown” in this string. We can use the match method as follows:

match_data = str.match(/brown/)

In this example, we used a regular expression pattern /brown/ to match against the string. The match method returns a MatchData object that contains information about the match. We assigned this object to the variable match_data.

We can now use various methods on the MatchData object to get information about the match. For example, we can use the to_s method to get the actual string that matched the pattern:

matched_string = match_data.to_s
puts matched_string #=> "brown"

We can also use the pre_match and post_match methods to get the portions of the string that appeared before and after the matched substring:

before_string = match_data.pre_match
puts before_string #=> "The quick "
after_string = match_data.post_match
puts after_string #=> " fox jumps over the lazy dog."

If the regular expression pattern contains groups (enclosed in parentheses), we can use the [] operator on the MatchData object to get the portions of the string that matched each group:

str = "John Doe,123 Main St.,Anytown,USA"
match_data = str.match(/(\w+) (\w+),(\d+) (\w+\.),(\w+)/)
puts match_data[0] #=> "John Doe,123 Main St.,Anytown,USA"
puts match_data[1] #=> "John"
puts match_data[2] #=> "Doe"
puts match_data[3] #=> "123"
puts match_data[4] #=> "Main St."
puts match_data[5] #=> "Anytown"
puts match_data[6] #=> "USA"

In this example, we used a regular expression pattern with six groups to match against the string. We then used the [] operator on the MatchData object to get the portions of the string that matched each group.

#Ruby