gsub in Ruby

Implementation of the gsub Method in Ruby

In the section of the article “gsub in Ruby”, the implementation of the gsub method in Ruby will be discussed. Here are some examples of how we can learn to implement the gsub method in Ruby.

Replacing Pattern

In this example, we will replace the pattern with the specified value and use the replacement overload in the gsub method.

• Ruby

Ruby

str = "I love chess and chess is a board game"
new_str = str.gsub("chess", "ludo")
puts new_str

You can also try this code with Online Ruby Compiler

Run Code

Output

Explanation

In the above code, there is a given string “str”, and this “str” string is used with the method gsub with the arguments ‘chess’ and ‘ludo’ where all the occurrences of ‘chess’ will be replaced with ‘ludo’.

LowerCase to UpperCase

In this example, we will convert all the lowercase words in the string to the uppercase of their equivalent words, where the matching overload will be used in the gsub method in Ruby:

• Ruby

Ruby

str = "I am a Ninja Coder"
new_str = str.gsub(/\w+/) { |match| match.upcase }
puts new_str

You can also try this code with Online Ruby Compiler

Run Code

Output

Explanation

In the above code, there is a given string “str”, and this “str” string is used with the method gsub with the arguments ‘w+’ where w represents all the word characters and + represents all the characters match one or more times. In the matching overload, uppercase is passed, converting lower case to upper case.

Replacing Patterns with Hash Values

In this example, we will replace the patterns with their hash values passed in the hash value overload of the gsub method:

• Ruby

Ruby

str = "Ninja Coder"

new_str = str.gsub(/[iaoe]/, 'i' => '+', 'a' => '#', 'o' => '=', 'e' => '*')

puts new_str

You can also try this code with Online Ruby Compiler

Run Code

Output

Explanation

In the above code, there is a given string “str”, and this “str” string is used with the method gsub where the first argument is the set of characters including i, a, o, and e. The second argument is the hash values mapping with each character passed in the first argument.

Frequently Asked Questions

What is the sub method in Ruby?

The sub is a method in Ruby that is basically used to replace the first occurrence of the pattern in the string with the specified string in the sub method arguments.

How the gsub method is different from the sub method in Ruby?

In the gsub method, all the occurrences of the pattern in the string with the specified string, and in the sub method, only the first occurrence of the pattern will be replaced.

Is gsub in Ruby case-sensitive?

Yes, the gsub method while calling in Ruby is case-sensitive by default, and the regular expression in the argument of the gsub method can be made a case-sensitive string in Ruby.

What if the pattern isn't found in a string?

If the pattern isn't found in the string, the gsub method in Ruby will return a copy of the original string without any modifications, and no replacements will be made.

Conclusion

The gsub method in Ruby is a built-in method that is basically used to replace all the occurrences of a pattern with the specified string, which returns a new string. The gsub method in Ruby has three overloads: a replacement, hash value, and matching overload.

In the article “gsub in Ruby”, we discussed the gsub method in Ruby with its syntax, parameters, return type, and implementation of the gsub method. Here are more articles that are recommended to read:

• What is Ruby?
• Why Ruby is so popular?
• History of Ruby
• Methods of Ruby
• Modules of Ruby
   

You can refer to our guided paths on the Coding Ninjas. You can check our course to learn more about DSA, DBMS, Competitive Programming, Python, Java, JavaScript, etc. 

Also, check out some of the Guided Paths on topics such as Data Structure and Algorithms, Competitive Programming, Operating Systems, Computer Networks, DBMS, and System Design, etc. as well as some Contests, Test Series, and Interview Experiences curated by top Industry Experts.

Happy Learning!