WLScripting.com » Math

Calculate a percentage

Daniel — Tue, 24 Mar 2009 16:59:25 +0000

Below is a quick function that simplifies the process of calculating a percentage in PHP.

function percent($Amount = 0, $Total = 0, $Decimal = 0) {
	// Make sure our numbers are actually numbers
	$Amount = (INT) $Amount;
	$Total = (INT) $Total;
	$Decimal = (INT) $Decimal;
	// Cannot divide by zero so check if Total = 0
	if ($Total === 0) {
		return 0;
	}
	$p = $Amount / $Total;
	// Multiply by 100 to move decimal point to correct location
	$p *= 100;
	// Return the percentage with specified decimal places
	return number_format($p, $Decimal);
}
?>

Then to use this code you can do:

// prints out 10% on the screen
echo percent(10, 100),'%';
?>

Add suffix to a number

Daniel — Tue, 24 Mar 2009 16:03:01 +0000

Have you ever had to dynamically add the suffix to a number? (ie. st, nd, rd, th)

function number_suffix($i) {
    switch( floor($i/10) % 10 ) {
        default:
	    switch( $i % 10 ) {
                case 1: return 'st';
                case 2: return 'nd';
                case 3: return 'rd';  
            }
        case 1:
    }
    return 'th';
}
?>

Then to use the code you would do like:

$number = 10;
// This will display 10th
echo $number,number_suffix($number);
?>

Zero fill a number

Daniel — Mon, 16 Mar 2009 14:42:46 +0000

An updated posting on this subject can be found at:
Working with zero filled numbers in PHP

Have you ever needed to make sure your number is a certain length for output? Say you have the number 5 but need to make sure it is 3 digits and out put like: 005. How would you go about this? One way to do this is the following:

function zerofill ($num,$zerofill) {
    // Get the current string length of the original number
    // Loop through that number until it has reached the count in $zerofill
    while (strlen($num)<$zerofill) {
        $num = "0".$num;
    }
    return $num;
}
?>

The usage of this code would be:

// Output will be 005
echo zerofill(5, 3);
?>

Enjoy!