php regex to extract single parameter value from string

Question

I'm working with a string containing parameters, separated by some special characters in PHP with preg_match

An example could be like this one, which has four parameters.

1stparm?#?1111?@?2ndParm?#?2222?@?3rdParm?#?3333?@?4thparm?#?444?@?

Each parameter name is followed by ?#?, and its value is right next to it, ending with ?@? (note: values can be strings or numbers, and even special characters)

I've probably overcomplicated my regex, which works in SOME cases, but not if I search for the last parameter in the string..

This example returns 2222 as the correct value (in group 1) for 2ndParm

(?:.*)2ndParm\?#\?(.*?)\?@\?(?=.)(.*)

but it fails if 2ndParm is the last one in the string as in the following example:

1stparm?#?1111?@?2ndParm?#?2222?@?

I'd also appreciate help in just returning one group with my result.. i havent been able to do so, but since I always get the one I'm interested in group 1, I can get it easily anyway.

Casimir et Hippolyte · Accepted Answer · 2020-04-07 23:19:11Z

2

Without regex:

$str ='1stparm?#?1111?@?2ndParm?#?2222?@?3rdParm?#?3333?@?4thparm?#?444?@?';

$keyval = explode('?@?', trim($str, '?@'));

$result = [];

foreach($keyval as $item) {
    [$key, $result[$key]] = explode('?#?', $item);
}

print_r($result);

demo

answered Apr 7, 2020 at 23:19

Casimir et Hippolyte

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2 Comments

Jan Over a year ago

Nice answer - ++.

msks2007 Over a year ago

agreed. nice and short... I became obsessed with regex, and was too focused to look elsewhere.

Sammitch · Accepted Answer · 2020-04-07 23:22:23Z

2

You don't need to use a regex for everything, and you should have a serious talk with whoever invented this horrid format about the fact that JSON, YAML, TOML, XML, etc exist.

function bizarre_unserialize($in) {
    $tmp = explode('?@?', $in);
    $tmp = array_filter($tmp); // remove empty
    $tmp = array_map(
        function($a) { return explode('?#?', $a); },
        $tmp
    );
    // rearrange to key-value
    return array_combine(array_column($tmp, 0), array_column($tmp, 1));
}

$input = '1stparm?#?1111?@?2ndParm?#?2222?@?3rdParm?#?3333?@?4thparm?#?444?@?';

var_dump(
    bizarre_unserialize($input)
);

Output:

array(4) {
  ["1stparm"]=>
  string(4) "1111"
  ["2ndParm"]=>
  string(4) "2222"
  ["3rdParm"]=>
  string(4) "3333"
  ["4thparm"]=>
  string(3) "444"
}

answered Apr 7, 2020 at 23:22

Sammitch

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1 Comment

msks2007 Over a year ago

the format is internally used by the scriptcase RAD. it POSTs user parameters inside a single parameter called nmgp_parms with the format shown. A very useful solution yours too.

Jan · Accepted Answer · 2020-04-07 23:16:01Z

1

You can use

(?P<key>.+?)
\Q?#?\E
(?P<value>.+?)
\Q?@?\E

in verbose mode, see a demo on regex101.com.

The \Q...\E construct disables the ? and # "super-powers" (no need to escape them here).

In PHP this could be

<?php
$string = "1stparm?#?1111?@?2ndParm?#?2222?@?3rdParm?#?3333?@?4thparm?#?444?@?";

$regex = "~(?P<key>.+?)\Q?#?\E(?P<value>.+?)\Q?@?\E~";

preg_match_all($regex, $string, $matches, PREG_SET_ORDER);

foreach ($matches as $match) {
    echo $match["key"] . " = " . $match["value"] . "\n";
}

?>

Which yields

1stparm = 1111
2ndParm = 2222
3rdParm = 3333
4thparm = 444

Or shorter:

$result = array_map(
    function($x) {return array($x["key"] => $x["value"]);}, $matches);
print_r($result);

edited Apr 7, 2020 at 23:16

answered Apr 7, 2020 at 22:58

Jan

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