PHP字符串模式任务

A simple problem.

I have the following string "48063974806397"

You will notice that this is just "4806397" repeated twice.

I need a way to recognize the repeat point, and just get the first instance of the pattern. E.g final return should just be "4806397".

(The length of the first number will not always be the same.)

I wanted to return this a variable in php.

How could I do this?

Thanks

If it's always just a string duplicated twice, then it's as simple as just taking the first half of the string:

$halfstring = substr($string, 0, strlen($string) / 2);

Use strlen() to get the length of the string, and divide that by 2. Then use substr() to just get the first half.

If that's always a number, math helps:

$halfStr = $n / (pow(10, strlen($n) / 2) + 1);