How can I detect repeating characters in php?

Question

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PHP - Need to remove duplicate characters within a String but would like to include exceptions

I have a string of text below in php.

$string = "@@@@@@ CHECK ME OUT! @@@@@@@@";

or

$string = "//////// CHECK ME OUT! ////////";

The will pretty much will use any character word or key to stand out from the rest when they post. My question is, is there a function or something I can use to prevent people from spamming a key or character.

So if what ever character or key is used more then three times it will remove it. So it will look like this below.

$string = "CHECK ME OUT!";

Thanks

sounds like a bad approach - do you require a log in to post? use a CAPTCHA? — , Jul 29 '12 at 21:19
This would be difficult, because what's to say the script takes out the double-f in the world 'difficult'? — David, Jul 29 '12 at 21:19
and in some languages there are words with 3+ consecutive letters — , Jul 29 '12 at 21:20

score 3 · Accepted Answer · edited May 23 '17 at 11:43

3

Sure, just use a regular expression to match a repeated character:

$string = "//////// CHECK ME OUT! ////////";
echo preg_replace('/(.)\1{3,}/', '', $string);

edited May 23 '17 at 11:43

Community

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answered Jul 29 '12 at 21:20

phihag

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score 1 · Answer 2 · answered Jul 29 '12 at 21:22

You can supply a charlist in trim.

$string = "//////// CHECK ME OUT! ////////";
echo trim($string, "/\$@");

This will trim (from front and end of string) any character in the list. No strings should being or end with /\%@ so that should be a pretty safe thing to do.

score 0 · Answer 3 · answered Jul 29 '12 at 21:20

0

$string = preg_replace('/(.)\1\1+/', '', $string);

answered Jul 29 '12 at 21:20

Michael Robinson

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How can I detect repeating characters in php?

3 Answers3