Round DOWN to nearest half integer in PHP - php

Question

I need a PHP function that will take a float and round it down to the nearest half (x.0 or x.5). I found other functions that will round to the nearest fraction, but they round both ways.
The function I need can only round down.
Examples
7.778 -> 7.5
7.501 -> 7.5
7.49 -> 7.0
7.1 -> 7.0

Answer 1

$x = floor($x * 2) / 2;

Answer 2

I'm assuming PHP has a floor function: floor($num * 2) / 2 ought to do it.

Answer 3

A easy solution is to use modulo operator (fmod() function), like this :
function roundDown($number, $nearest){
return $number - fmod($number, $nearest);
}
var_dump(roundDown(7.778, 0.5));
var_dump(roundDown(7.501, 0.5));
var_dump(roundDown(7.49, 0.5));
var_dump(roundDown(7.1, 0.5));
And the result :
The advantage it's that work with any nearest number (0.75, 22.5, 3.14 ...)
You can use the same operator to roundUp :
function roundUp($number, $nearest){
return $number + ($nearest - fmod($number, $nearest));
}
var_dump(roundUp(7.778, 0.5));
var_dump(roundUp(7.501, 0.5));
var_dump(roundUp(7.49, 0.5));
var_dump(roundUp(7.1, 0.5));

Answer 4

You can do it on that way round($number / 5, 1) * 5 the second parameter in the round() is the precision.
Example with $number equal to 4.6, 4.8 and 4.75
>>> round(4.6 / 5, 1) * 5;
=> 4.5
>>> round(4.8 / 5, 1) * 5;
=> 5.0
>>> round(4.75 / 5, 1) * 5;
=> 5.0
If you want you can round() down too like round($number, 1, PHP_ROUND_HALF_DOWN) check the documentation for more information https://www.php.net/manual/en/function.round.php

Answer 5

echo round($val*2) / 2; // Done

Answer 6

From my job's requirements. I put an function to do this. Hope you can view it as a reference:
function round_half_five($no) {
$no = strval($no);
$no = explode('.', $no);
$decimal = floatval('0.'.substr($no[1],0,2)); // cut only 2 number
if($decimal > 0) {
if($decimal <= 0.5) {
return floatval($no[0]) + 0.5;
} elseif($decimal > 0.5 && $decimal <= 0.99) {
return floatval($no[0]) + 1;
}
} else {
return floatval($no);
}
}