Regular expression matching contains special characters

<code>    $info = array(
        "https://segmentfault.com/q/1010000003711515",
        "http://www.baidu.com?admin.php&jasdhjas=asjd",
        'php $a=0; echo "abc";',
        "假如这是第三个....*^%$#@!()[]{}",
        );
    foreach ($info as $key => $value) {
        $message = "https://segmentfault.com/q/1010000003711515";
        $preg = "/^".$value."$/";
        if (preg_match($preg, $message)) {
            echo '匹配成功';
            break;
        }
    }</code>

Traverse the $info array, add /^, $/ before and after each string, and turn it into a regular expression to match the provided $message, but because of the inside of $info The string may have special characters, causing errors, so is there any way to escape each string of $info?

Can it only be escaped when defining $info?

Reply content:

<code>    $info = array(
        "https://segmentfault.com/q/1010000003711515",
        "http://www.baidu.com?admin.php&jasdhjas=asjd",
        'php $a=0; echo "abc";',
        "假如这是第三个....*^%$#@!()[]{}",
        );
    foreach ($info as $key => $value) {
        $message = "https://segmentfault.com/q/1010000003711515";
        $preg = "/^".$value."$/";
        if (preg_match($preg, $message)) {
            echo '匹配成功';
            break;
        }
    }</code>

Traverse the $info array, add /^, $/ before and after each string, and turn it into a regular expression to match the provided $message, but because of the inside of $info The string may have special characters, causing errors, so is there any way to escape each string of $info?

Can it only be escaped when defining $info?

/ has special meaning in regular expressions, so the following '/' will cause an error. You need to add a backslash in front of it to escape it.

$preg is defined, but $info is used. This is a mistake
Also, regular wildcards must be escaped with .
Your example above should be rewritten as

<code>$preg = "/^https:\/\/segmentfault\.com\/q\/1010000003711515$/";
    $test = "https://segmentfault.com/q/1010000003711515";
    preg_match($preg, $test);</code>

I think it’s better if you just say what you want to do directly. I feel like your thinking is wrong.
$preg is an unknown variable
Your premise is too big

If these expressions were entered by programmers, then it is the programmer's problem.

If these expressions are entered by users, then the user should be informed on the entry interface that these are regular expressions so that he can pay attention to them.

You can use js to escape the special characters of the regular expression, but it may cause double escaping (for example, the user originally entered the escaped content http:|b4831e42daf1db770cdbc01d41578e020|/.+)
Example

<code>document.getElementById('test').value = (new RegExp(document.getElementById('test').value)).toString();</code>

In addition, if you forcibly add /^ and $/ in the program, it may also cause problems.