php - 在字符串中查找匹配项

Question

I'm trying to work out how to find a match in a string. I'm looking for a match on any of the following - = ? [] ~ # ! 0 - 9 A-Z a-z and I need to know what its matched on .

Eg: matched on !, or matched on = and # and ?

Normally I'd use this:

$a = 'How are you?';

if (strpos($a, 'are') !== false) {
    echo 'true';
}

However I'm not sure how to do that so it looks up the characters needed. Also where I may have [], It could be [] or [xxxx] where xxxx could be any number of alpha numeric characters.

I need to match and any of the characters listed, return the characters so I know what was matched and if the [] contain any value return that as well.

Eg:

$a = 'DeviceLocation[West12]'; Would return: $match = '[]'; $match_val= 'West12';

$a = '#=Device'; Would return:$match = '#,=';

$a= '?[1234]=#Martin'; Would return: $match = '?, [], =, #'; $match_val= '1234';

Can any one advise how I can do this. Thanks

Answer 1

Well, that requirements are a bit vague, but that is what I deduced:

1) if there is an alphanumeric string inside square brackets get it as a separate value
2) all other mentioned chars should be matched one by one and then imploded.

You may use the following regex to get the values you need:

$re = '@\[([a-zA-Z0-9]+)\]|[][=?~#!]@';

Details:

• \[ - a [
• ([a-zA-Z0-9]+) - Group 1 value capturing 1 or more alphanumeric symbols
• \] - a closing ]
• | - or
• [][=?~#!] - a single char, one of the defined chars in the set.

See the regex demo. The most important here is the code that gets the matches (feel free to adapt):

$re = '@\[([a-zA-Z0-9]+)\]|[][=?~#!]@';
$strs =array('DeviceLocation[West12]', '#=Device', '?[1234]=#Martin');

foreach ($strs as $str) {
    preg_match_all($re, $str, $matches, PREG_SET_ORDER);
    $results = array();
    $match_val = "";
    foreach ($matches as $m) {
        if (!empty($m[1])) {
            $match_val = trim($m[1], "[]");
            array_push($results, "[]");
        } else {
            array_push($results, $m[0]);
        } 
    }
    echo "Value: " . $match_val . "
";
    echo "Symbols: " . implode(", ", $results);
    echo "
-----
";
}

See the PHP demo

Output:

Value: West12
Symbols: []
-----
Value: 
Symbols: #, =
-----
Value: 1234
Symbols: ?, [], =, #
-----