[RESOLVED] Regex and preg_replace on delimited variable.

wonder_bread23

Hello Everyone,

Hoping for a bit of guidance and place to start on the following coding issue.

I have a variable that is a string of delimited numbers:

$myvar = '1|4|5|21|5|6|8';

I want my PHP script to look for a specific number in $myvar and then update it in sequence with a marker directly after the searched for number. I was using str_replace to accomplish this as follows:

//Old variable to be updated
$myvar = '1|4|5|21|5|6|8';

//Number to search for
$search = '1';

//Marker
$marker = 'm';

//Use str_replace to create an updated variable
$newvar = str_replace($search, $search . '|' . $marker, $myvar);

The issue with this code is that it works for the first '1' within the delimited variable, but also replaces any other number with a '1' in it. I've considered blowing the variable up into an array and the doing the replacement there, but am concerned with the overhead this would cause. I believe preg_replace would probably be a less intensive process, but I'm having a difficult time writing a regex that would search and replace correctly. Any help is greatly appreciated!

Thanks!

bradgrafelman

wonder_bread23;10987652 wrote:
I've considered blowing the variable up into an array and the doing the replacement there, but am concerned with the overhead this would cause.

The overhead would be minimal, and this is the solution I would suggest.

wonder_bread23;10987652 wrote:
I believe preg_replace would probably be a less intensive process, but I'm having a difficult time writing a regex that would search and replace correctly.

Depends; PCRE operations can actually be quite expensive as compared to basic string/array operations.

EDIT: If you wanted to test the PCRE route, the regexp could be:

/(?<=^|\|)123(?=$|\|)/

(where '123' is the desired entry/datum to search for).

EDIT2: Guess you could simplify it down to:

/\b123\b/

instead.

wonder_bread23

Thank you. I'll go ahead and go the route of manipulating the arrays as it seems this is the most efficient route. Thank you for the regex help... very informative.