How to mark boldly sequentially triplicate and quadruplicate characters in a string?

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#1 by (13 votes)

8

I want to mark the triplicate and quadruplicate sequences of a string like this:

$string = "AAACDEAAAABBBUUDD";

And I would like to get the following result:

<b>AAA</b>CDE<b>AAAA</b><b>BBB</b>UUDD

php javascript

asked by anonymous 22.05.2017 / 19:03

1 answer

Is it worth using the W3C validator? What is the "dirname" attribute in HTML?

score 13 · Accepted Answer

   $string = 'AAACDEAAAABBBUUDD';
   $bold = preg_replace( '/(.){2,}/', '<b>$0</b>' , $string );

See working at IDEONE

var str = "AAACDEAAAABBBUUDD";
var res = str.replace( /(.){2,}/g, "<b>$&</b>");

See working at IDEONE

(.) = any character (change by (\S) if you do not want spaces);
= the character previously mentioned by the first group (.) ;
{2,} two or more occurrences of the previous character. If you only want sequences of three or four characters, disregarding five or more, replace with {2,3} (original plus two equals, or original plus three equals).

That is, with each iterated character, we see if it is followed by 2 more occurrences of it, totaling the 3 or more desired.

Replacing <b>$0</b> ( $& in JS) takes the whole set found, and adds bold .