PHP dropping decimals without rounding up

Question

I want to drop off decimals without rounding up. For example if I have 1.505, I want to drop last decimal and value should be 1.50. Is there such a function in PHP?

Answer 1

The answers of RenaPot, IsisCode, goredwards are not correct.

Because of how float works in computers (in general), float is not accurate.

To replicate the issue:

floor(19.99 * 100);  // Outputs 1998 instead of 1999
floor( 5.10 * 100);  // Outputs  509 instead of  510

Within PHP internally, 19.99 * 100 results in something like 1998.999999999999999, which when we do floor of that, we get 1998.

Solution:

Solution 1: Use bcmath library (Suggested by @SamyMassoud) if you have it installed (some shared hosting servers may not have it installed by default). Like so:

//floor(19.99 * 100);// Original
floor(bcmul(19.99, 100));// Outputs 1999

Solution 2: String manipulation (my recommendation):

// Works with positive and negative numbers, and integers and floats and strings
function withoutRounding($number, $total_decimals) {
    $number = (string)$number;
    if($number === '') {
        $number = '0';
    }
    if(strpos($number, '.') === false) {
        $number .= '.';
    }
    $number_arr = explode('.', $number);

    $decimals = substr($number_arr[1], 0, $total_decimals);
    if($decimals === false) {
        $decimals = '0';
    }

    $return = '';
    if($total_decimals == 0) {
        $return = $number_arr[0];
    } else {
        if(strlen($decimals) < $total_decimals) {
            $decimals = str_pad($decimals, $total_decimals, '0', STR_PAD_RIGHT);
        }
        $return = $number_arr[0] . '.' . $decimals;
    }
    return $return;
}

// How to use:
withoutRounding(19.99, 2);// Return "19.99"
withoutRounding(1.505, 2);// Return "1.50"
withoutRounding(5.1, 2);// Return "5.10"