验证PHP中的浮点值

Question

I started learning PHP to do some pet project, and I am trying to get this around my head on how to validate a valid float or double in PHP

Supposed I have this code in HTML that ask for interest rate

<input type="text" name="interest" size="5" >

In My PHP code, I wanted to validate if this is a valid interest rate:

<?php       
    $interest = $_POST['interest']
    //isset - empty test (not- shown)
    if(!is_numeric($interest) && is_float($interest)){
        print "<p><span class='error'>Interest should be numeric</span></p>";
    }
?>

I have my is_numeric() test first then I coupled it with the is_float() test but when I enter "1." (note the "." after the number) it should catch this but apparently not. I am not sure why "1." is a valid floating variable in PHP.

Answer 1

its probabaly best to define the input tag as a Number

<input type="number" name="interest" size="5" >

you can check with php to see if it's a number or not

foreach ($interest as $element) {
    if (is_numeric($element)) {
        echo "'{$element}' is numeric", PHP_EOL;
    } else {
        echo "'{$element}' is NOT numeric", PHP_EOL;
    }
}

source: http://php.net/manual/en/function.is-numeric.php