regular expression word preceded by char - php

Question

I want to grab a specific string only if a certain word is followed by a = sign.
Also, I want to get all the info after that = sign until a / is reached or the string ends.
Let's take into example:
somestring.bla/test=123/ohboy/item/item=capture
I want to get item=capture but not item alone.
I was thinking about using lookaheads but I'm not sure it this is the way to go. I appreciate any help as I'm trying to grasp more and more about regular expressions.

Answer 1

[^/=]*=[^/]*
will give you all the pairs that match your requirements.
So from your example it should return:
test=123
item=capture
Refiddle Demo

Answer 2

If you want to capture item=capture, it is straightforward:
/item=[^\/]*/
If you want to also extract the value,
/item=([^\/]*)/
If you only want to match the value, then you need to use a look-behind.
/(?<=item=)[^\/]*/
EDIT: too many errors due to insomnia. Also, screw PHP and its failure to disregard separators in a character group as separators.

Answer 3

Here is a function I wrote some time ago. I modified it a little, and added the $keys argument so that you can specify valid keys:
function getKeyValue($string, Array $keys = null) {
$keys = (empty($keys) ? '[\w\d]+' : implode('|', $keys));
$pattern = "/(?<=\/|$)(?P<key>{$keys})\s*=\s*(?P<value>.+?)(?=\/|$)/";
preg_match_all($pattern, $string, $matches, PREG_SET_ORDER);
foreach ($matches as & $match) {
foreach ($match as $key => $value) {
if (is_int($key)) {
unset($match[$key]);
}
}
}
return $matches ?: FALSE;
}
Just trow in the string and valid keys:
$string = 'somestring.bla/test=123/ohboy/item/item=capture';
$keys = array('test', 'item');
$keyValuePairs = getKeyValue($string, $keys);
var_dump($keyValuePairs);