Question

In PHP the bindec()function can be used to convert a binary number to decimal, but there is no error checking to test if the binary number string is valid. What happens is that something like bindec('1051'); returns 5 instead of an error.

Is there an efficient way to validate if the number is a binary string?

Answer 1

if (preg_match('~^[01]+$~', $num)) {
    // valid binary number
}