Question

I have a RegEx that is working for me but I don’t know WHY it is working for me. I’ll explain.

RegEx: \s*<in.*='(<?.*?>)'\s*/>\s* 

Text it finds (it finds the white-space before and after the input tag):

<td class='style9'>       <input name='guarantor4' id='guarantor4' size='50' type='text' tabindex='10' value='<?php echo $data[guarantor4]; ?>'  />    </td> </tr> 

The part I don’t understand:

<in.*=' <--- As I understand it, this should only find up to the first =' as in it should only find <input name='  It actually finds: <input name='guarantor4' id='guarantor4' size='50' type='text' tabindex='10' value=' which happened to be what I was trying to do. 

What am I not understanding about this RegEx?

Answer 1

You appear to be using ‘greedy’ matching.

Greedy matching says ‘eat as much as possible to make this work’

try with

<in[^=]*=   

for starters, that will stop it matching the ‘=’ as part of ‘.*’

but in future, you might want to read up on the

.*?   

and

.+? 

notation, which stops at the first possible condtion that matches instead of the last.

The use of ‘non-greedy’ syntax would be better if you were trying to only stop when you saw TWO characters,

ie:

<in.*?=id 

which would stop on the first ‘=id’ regardless of whether or not there are ‘=’ in between.