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Detecting Duplicate Words

Problem

A common writing mistake is to repeat repeat a word. You want to detect doubled words in a string.

Solution

We use Perl compatible regular expressions like this:

(require (lib "pregexp.ss"))

(pregexp-match "\\b(\\S+)\\b(\\s+\\1\\b)+"
               "This is a small small test")

; => ("small small" "small" " small")

(pregexp-match-positions "\\b(\\S+)\\b(\\s+\\1\\b)+"
                         "This is a small small test")

; => ((10 . 21) (10 . 15) (15 . 21))

Discussion

An explanation of the regular expression is found in the Perl Cookbook Detecting Duplicate Words.

Comments about this recipe

Contributors

-- NoelWelsh - 25 Jun 2004 -- JensAxelSoegaard - 25 Oct 2004