Parsing attributes in PHP using regular expressions - php

Question

Consider that i have the string,
$string = 'tag2 display="users" limit="5"';
Using the preg_match_all function, i need to get the output
Required o/p
Array
(
[0] => Array
(
[0] => tag2
[1] => tag2
[2] =>
)
[1] => Array
(
[0] => display="users"
[1] => display
[2] => users
)
[2] => Array
(
[0] => limit="5"
[1] => limit
[2] => 5
)
)
I tried using this pattern '/([^=\s]+)="([^"]+)"/' but it is not recognizing the parameter with no value (in this case tag2) Instead it gives the output
What I am getting
Array
(
[0] => Array
(
[0] => display="users"
[1] => display
[2] => users
)
[1] => Array
(
[0] => limit="5"
[1] => limit
[2] => 5
)
)
What will be the pattern for getting the required output ?
EDIT 1: I also need to get the attributes which are not wrapped with quotes ex: attr=val. Sorry for not mentioning before.

Answer 1

Try this:
<?php
$string = 'tag2 display="users" limit="5"';
preg_match_all('/([^=\s]+)(="([^"]+)")?/', $string, $res);
foreach ($res[0] as $r => $v) {
$o[] = array($res[0][$r], $res[1][$r], $res[3][$r]);
}
print_r($o);
?>
It outputs me:
Array
(
[0] => Array
(
[0] => tag2
[1] => tag2
[2] =>
)
[1] => Array
(
[0] => display="users"
[1] => display
[2] => users
)
[2] => Array
(
[0] => limit="5"
[1] => limit
[2] => 5
)
)

Answer 2

I think it's not fully possible to give you with one call what you're looking for, but this is pretty close:
$string = 'tag2 display="users" limit=5';
preg_match_all('/([^=\s]+)(?:="?([^"]+)"?|())?/', $string, $res, PREG_SET_ORDER);
print_r($res);
Output:
Array
(
[0] => Array
(
[0] => tag2
[1] => tag2
[2] =>
[3] =>
)
[1] => Array
(
[0] => display="users"
[1] => display
[2] => users
)
[2] => Array
(
[0] => limit=5
[1] => limit
[2] => 5
)
)
As you can see, the first element has no value, I tried to work around that and offer an empty match now. So this builds the array you were asking for, but has an additional entry on the empty attribute.
However the main point is the PREG_SET_ORDER flag of preg_match_all. Maybe you can live with this output already.

Answer 3

Maybe you're interested in this litte snippet that parses all sorts of attribute styles. <div class="hello" id=foobar style='display:none'> is valid html(5), not pretty, I know…
<?php
$string = '<tag2 display="users" limit="5">';
$attributes = array();
$pattern = "/\s+(?<name>[a-z0-9-]+)=(((?<quotes>['\"])(?<value>.*?)\k<quotes>)|(?<value2>[^'\" ]+))/i";
preg_match_all($pattern, $source, $matches, PREG_SET_ORDER);
foreach ($matches as $match) {
$attributes[$match['name']] = $match['value'] ?: $match['value2'];
}
var_dump($attributes);
will give you
$attributes = array(
'display' => 'users',
'limit' => '5',
);