PHP preg_match_all expression - php

Question

I have virtually no experience of regx, but trying my best.
I have a string like this:
$fString = "Name=Sök,Value=2,Title=Combine me,Options=[Item1=1,Item2=2,Item3=3]";
I want to get an array looking like this:
Array[0] = "Name=Sök"
Array[1] = "Value=2"
Array[2] = "Title=Combine me"
Array[3] = "Options=[Item1=1,Item2=2,Item3=3]"
What I have managed to do so far is:
preg_match_all("/[^,]*[\w\d]*=[^,]*/",$fString,$Data);
But it I can't figure out how to fix the last "Option".
Array ( [0] => Array ( [0] => Name=S�k [1] => Value=2 [2] => Title=Combine me [3] => Options=[Item1=1 [4] => Item2=2 [5] => Item3=3] ) )
...and why is the result an array inside an array?!?
[EDIT]
I guess I need to explain the whole idea of what I'm trying to do here, I'm not sure I'm on the right track any more.
I have created some classes where I store all the "persistent" variables in an array. I have a function that serializes this array so I can be stored in a database.
I know all about the serialize() function, but I'm doing some filtering so I can't use it as it is, and I also prefer to have it more readable for manual editing. This array can have nested arrays within, that needs to be preserved. When I read it all back from the database, the original array must be created again.
I had it all working with the eval() command but stumbled into trouble where I had nested arrays because of the " or ' characters was breaking the main outer string. So this approach was an attempt to serialize everything without nested strings that needed to be preserved.
So if I can solve the nested data with preg_match_all I'm there, otherwise I need to come up with another solution.
I guess the data needs to be escaped as well, such as the , and [ ]

Answer 1

Here is a function that will do basically what you need:
function explode_me($str) {
$a = array();
$v = "";
$ignore = false;
for ($i = 0; $i < strlen($str); $i++) {
if ($str[$i] == ',' && !$ignore) {
$a[] = $v;
$v = "";
}
else if ($str[$i] == '[' && !$ignore) {
$ignore = true;
$v .= $str[$i];
}
else if ($str[$i] == ']' && $ignore) {
$ignore = false;
$v .= $str[$i];
}
else {
$v .= $str[$i];
}
}
$a[] = $v;
return $a;
}
To test it:
$str = "Name=Sök,Value=2,Title=Combine me,Options=[Item1=1,Item2=2,Item3=3]";
$a = explode_me($str);
print_r($a);
which prints:
Array
(
[0] => Name=Sök
[1] => Value=2
[2] => Title=Combine me
[3] => Options=[Item1=1,Item2=2,Item3=3]
)

Answer 2

(\w+)=(\[[^\]]+\]|[^,]+)
This breaks down as:
(\w+) # a word (store in match group 1)
= # the "=" character
( # begin match group 2
\[ # a "[" character
[^\]]+ # anything but "]" character
\] # a "]" character
| # or...
[^,]+ # anything but a comma
) # end match group 1
Apply with preg_match_all():
$fString = "Name=Sök,Value=2,Title=Combine me,Options=[Item1=1,Item2=2,Item3=3]";
$matches = array();
preg_match_all("/(\\w+)=(\\[[^\\]]+\\]|[^,]+)/", $fString, $matches);
Which results in something even more detailed than you wanted to have:
Array
(
[0] => Array
(
[0] => Name=Sök
[1] => Value=2
[2] => Title=Combine me
[3] => Options=[Item1=1,Item2=2,Item3=3]
)
[1] => Array
(
[0] => Name
[1] => Value
[2] => Title
[3] => Options
)
[2] => Array
(
[0] => Sök
[1] => 2
[2] => Combine me
[3] => [Item1=1,Item2=2,Item3=3]
)
)
$result[0] is what you wanted. $result[1] and $result[2] are property names and values separately, which enables you to use them right away instead of making an extra step that splits things like "Options=[Item1=1,Item2=2,Item3=3]" at the correct =.

Answer 3

If you could change the separators between the items (where it says Item1=1,Item2=2,Item3=3 to something like Item1=1|Item2=2|Item3=3) you could easily use explode(',',$fString) to convert a string to an array.
I can also offer this piece of code that will change the separators, as I have no experience with regex:
$newstr = str_replace(',Item','|Item',$fString);
$newarray = explode(',',$newstr);
$newarray will look like this:
Array[0] = "Name=Sök"
Array[1] = "Value=2"
Array[2] = "Title=Combine me"
Array[3] = "Options=[Item1=1|Item2=2|Item3=3]"

Answer 4

This is a problem that lends itself more to parsing than regex extraction. Bout you can separate the special case to make it work:
preg_match_all("/(\w+)=( \w[^,]+ | \[[^\]]+\] )/x", $str, $m);
$things = array_combine($m[1], $m[2]);
Will give you a PHP variable like (but you can access $m[0] for the unparsed strings):
[Name] => Sök
[Title] => Combine me
[Options] => [Item1=1,Item2=2,Item3=3]
You can reapply the function on Options to explode that too.
The trick again is differentiating between \w anything that starts with a letter, and the \[...\] enclosed options. There you have to just make it match ^] all non-closing-brackets, and that's it.

Answer 5

So, here is another approach. It's a mini parser for nested structures. Adapt the regex if you need escape codes.
function parse(&$s) {
while (strlen($s) && preg_match("/^(.*?)([=,\[\]])/", $s, $m)) {
$s = substr($s, 1 + strlen($m[1]));
switch ($m[2]) {
case "=":
$key = $m[1];
break;
case ",":
if (!isset($r[$key])) {
$r[$key] = $m[1];
}
break;
case "[":
$r[$key] = parse($s);
break;
case "]":
return $r;
}
}
if ($s) { $r[$key] = $s; } // remainder
return $r;
}