Ruby Search and Replace (original) (raw)
Last Updated : 25 Sep, 2019
sub and gsub string methods that use regular expressions, and their in-place variants are sub! and gsub!. The sub & sub! replaces the first occurrence of the pattern and gsub & gsub! replaces all occurrences. All of these methods perform a search-and-replace operation using a Regexp pattern. sub! and gsub! modify the string on which they are called whereas the sub and gsub returns a new string, leaving the original unmodified. Below is the example to understand it better.Example :
Ruby `
Ruby program of sub and gsub method in a string
roll = "2004-959-559 # This is Roll Number"
Delete Ruby-style comments
roll = roll.sub!(/#.*$/, "")
puts "Roll Num : #{roll}"
Remove anything other than digits
roll = roll.gsub!(/\D/, "")
puts "Roll Num : #{roll}"
`
Output :
Roll Num : 2004-959-559 Roll Num : 2004959559
In above example, we are using sub! and gsub!. here sub! replace first occurrence of the pattern and gsub! replaces all occurrences.Example :
Ruby `
Ruby program of sub and gsub method
text = "geeks for geeks, is a computer science portal"
Change "rails" to "Rails" throughout
text.gsub!("geeks", "Geeks")
Capitalize the word "Rails" throughout
text.gsub!(/\bgeeks\b/, "Geeks") puts "#{text}"
`
Output :
Geeks for Geeks, is a computer science portal
The gsub! method too can be used with a regular expression.