php - How to remove all non-numeric characters from a string?

Question

I'm trying to remove all non-numeric characters from my code, but FILTER_SANITIZE_NUMBER_INT allows plus and minus signs.

How can I remove them using PHP that I can add to my code?

Here is my code.

$a = filter_var($a, FILTER_SANITIZE_NUMBER_INT);

Answer 1

In this case, you may want to consider simply casting the result to an int to remove the plus (+) sign.

$a = (int) filter_var($a,FILTER_SANITIZE_NUMBER_INT);

If you need to drop the minus (-) sign as well, effectively getting the number's absolute value, use PHP's abs() function:

$a = abs((int) filter_var($a,FILTER_SANITIZE_NUMBER_INT));