Replace words of length exactly equal to 'n' using preg_replace()

Question

I have a string -

 $file_data = This is a sample text. This text will be used as a dummy text for various RegEx operations using PHP.

I want to replace every 4 letter word with *

The Regex I'm using is

preg_replace("/\w{4}/", "*", $file_data)

But this also replaces words with length >=4. I want it to be strictly 4. How should I do it?

Maybe a useful resource: On [Regexr](http://regexr.com/) you can fiddle around and validate your regex realltime. (Holy... sorry for that previous link... I thought it was .org o.o) — Xyv, Aug 27 '15 at 07:39

score 2 · Accepted Answer · answered Aug 27 '15 at 07:38

2

Try using a regular expression such as:

\b[a-zA-Z]{4}\b

The \bs ensure that the beginning and end of the four letter pattern [a-zA-Z]{4} are word boundaries.

answered Aug 27 '15 at 07:38

Moishe Lipsker

why did you change from `w` to `[a-zA-z]`? The previous one worked too – Siddharth Thevaril Aug 27 '15 at 07:41
1

@Sidsec9 `\w` also includes `_` – Moishe Lipsker Aug 27 '15 at 07:41

1 Answers1