php - check if a string contains a float

Question

What is the easiest way to check if a string contains a valid float?

For example

is_string_float("1") = true
is_string_float("1.234") = true
is_string_float("1.2e3") = true
is_string_float("1b2") = false
is_string_float("aldhjsfb") = false

Answer 1

If you really want to know if a string contains a float and ONLY a float you cannot use is_float() (wrong type) or is_numeric() (returns true for a string like "1" too) only. I'd use

<?php

    function foo(string $string) : bool {
        return is_numeric($string) && strpos($string, '.') !== false;
    }

?>

instead.