Finding duplicate words within a string regex C/W

Question

I'm currently dabbing in regex in Java, and want to try and find duplicate words in strings. If I inputted a string such as 'This this is great.'. I was using \\b(\\w+) \\1\\b, but that only recognizes two duplicate words, such as 'this this' in a string.

Any help regarding this?

Answer 1

Add the "ignore case" switch (?i) to your regex:

(?i)\\b(\\w+) \\1\\b

Alternatively, you could fold the input to lower case first:

input.toLowerCase()

Note: If you're using String.matches(), the regex must match the entire input, so you'd add .* to both ends of your regex:

.*(?i)\\b(\\w+) \\1\\b.*