Converting a string into a regular expression

[Axeia]

My head hurts from writing this thing:

private function convert2regex( $pStr )
{
    return preg_replace( '~(\[|\\|\^|\$|\.|\||\?|\*|\+|\(|\))~', '\\\$0', $pStr );
}

But that oughta do the job, right? Took all the characters with a special meaning , escaped them, used the or operator and captured the result to a backreference.

Then the backreference is prefixed with a backslash and the preg_replace puts in the proper spot.

[nrg_alpha]

My head hurts from writing this thing:

private function convert2regex( $pStr )
{
    return preg_replace( '~(\[|\\|\^|\$|\.|\||\?|\*|\+|\(|\))~', '\\\$0', $pStr );
}

But that oughta do the job, right?

 

Well, without an example string of what you are trying to capture, it's hard to say..

 

Alternations can be costly.. I would advise a character class instead of all these ORs...

return preg_replace( '~([\[^$.|?*+()\\\])~', '\\\$0', $pStr );// hope I didn't miss any characters

 

Perhaps seeing a complete string example before and with the desirable after effects would help illuminate what it is you are trying to accomplish if the above snippet doesn't serve well...

[Axeia]

Trying to convert basically ANY string into a regular expression.

So anything that has a special meaning in a regular expression has to be escaped.

 

Or that was the plan earlier today, using it atm for something a bit less random and so far so good.

[nrg_alpha]

You mean using something like preg_quote?

[Axeia]

Thanks -.-

 

I wonder why that didn't come up when I was searching for an existing solution, checked the php text functions to see if it was there (url_decode etc are, so was expecting this one to be there as well).