how to check if PHP variable contains non-numbers?

Question

I just want to know the method to check a PHP variable for any non-numbers and if it also detects spaces between characters? Need to make sure nothing weird gets put into my for

Answer 1

This worked out to be ~30% faster than preg_match for my test cases, while still letting you match any characters you want:

if( $a !== '' && trim($a, ' 1234567890.,') === '' ){
   print("The variable contains only digits, decimal separators and spaces");
}

This simply removes all characters supplied from the string. If the result is an empty string, you know it only contained those characters.