Regular Expression For Duplicate Words

regex duplicates capture-group
Joshua picture Joshua · May 12, 2010 · Viewed 95.3k times · Source

I'm a regular expression newbie, and I can't quite figure out how to write a single regular expression that would "match" any duplicate consecutive words such as:

Paris in the the spring.

Not that that is related.

Why are you laughing? Are my my regular expressions THAT bad??

Is there a single regular expression that will match ALL of the bold strings above?

Answer

Gumbo picture Gumbo · May 12, 2010

Try this regular expression:

\b(\w+)\s+\1\b

Here \b is a word boundary and \1 references the captured match of the first group.

Related questions

Regular expression to match a line that doesn't contain a word

I know it's possible to match a word and then reverse the matches using other tools (e.g. grep -v). However, is it possible to match lines that do not contain a specific word, e.g. hede, using a regular …

Read More
How to validate an email address in JavaScript

Is there a regular expression to validate an email address in JavaScript?

Read More
RegEx match open tags except XHTML self-contained tags

I need to match all of these opening tags: <p> <a href="foo"> But not these: <br /> <hr class="foo" /> I came up with this and wanted to make sure I've got …

Read More