round
Description
Syntax
round(
int|float $num,
int $precision = 0,
int $mode = PHP_ROUND_HALF_UP
): floatParameters
num
The value to round.
precision
The optional number of decimal digits to round to.
If the precision is positive, num is rounded to precision significant digits after the decimal point.
If the precision is negative, num is rounded to precision significant digits before the decimal point, i.e. to the nearest multiple of pow(10, -$precision), e.g. for a precision of -1 num is rounded to tens, for a precision of -2 to hundreds, etc.
mode
Use one of the following constants to specify the mode in which rounding occurs.
| Constants | Description |
|---|---|
| PHP_ROUND_HALF_UP | Rounds num away from zero when it is half way there, making 1.5 into 2 and -1.5 into -2. |
| PHP_ROUND_HALF_DOWN | Rounds num towards zero when it is half way there, making 1.5 into 1 and -1.5 into -1. |
| PHP_ROUND_HALF_EVEN | Rounds num towards the nearest even value when it is half way there, making both 1.5 and 2.5 into 2. |
| PHP_ROUND_HALF_ODD | Rounds num towards the nearest odd value when it is half way there, making 1.5 into 1 and 2.5 into 3. |
Return
The value rounded to the given precision as a float.
Examples
1 · num · down
<? $num = 1.4999; $return = round($num); echo $return; ?>
1
2 · num · up
<? $num = 1.5000; $return = round($num); echo $return; ?>
2
3 · precision
<?
$num = 5555.5555;
for($i = -5; $i <= 5; ++$i)
{
$precision = $i;
$return = round($num, $precision);
echo $precision . ": " . $return . PHP_EOL;
}
?>-5: 0 -4: 10000 -3: 6000 -2: 5600 -1: 5560 0: 5556 1: 5555.6 2: 5555.56 3: 5555.556 4: 5555.5555 5: 5555.5555
4 · mode · PHP_ROUND_HALF_UP
<?
$nums = [-2.5, -1.5, -0.5, 0.5, 1.5, 2.5];
$precision = 0;
$mode = PHP_ROUND_HALF_UP;
for($i = 0; $i < count($nums); ++$i)
{
$return = round($nums[$i], $precision, $mode);
echo $return . PHP_EOL;
}
?>-3 -2 -1 1 2 3
5 · mode · PHP_ROUND_HALF_DOWN
<?
$nums = [-2.5, -1.5, -0.5, 0.5, 1.5, 2.5];
$precision = 0;
$mode = PHP_ROUND_HALF_DOWN;
for($i = 0; $i < count($nums); ++$i)
{
$return = round($nums[$i], $precision, $mode);
echo $return . PHP_EOL;
}
?>-2 -1 0 0 1 2
6 · mode · PHP_ROUND_HALF_EVEN
<?
$nums = [-2.5, -1.5, -0.5, 0.5, 1.5, 2.5];
$precision = 0;
$mode = PHP_ROUND_HALF_EVEN;
for($i = 0; $i < count($nums); ++$i)
{
$return = round($nums[$i], $precision, $mode);
echo $return . PHP_EOL;
}
?>-2 -2 0 0 2 2
7 · mode · PHP_ROUND_HALF_ODD
<?
$nums = [-2.5, -1.5, -0.5, 0.5, 1.5, 2.5];
$precision = 0;
$mode = PHP_ROUND_HALF_ODD;
for($i = 0; $i < count($nums); ++$i)
{
$return = round($nums[$i], $precision, $mode);
echo $return . PHP_EOL;
}
?>-3 -1 -1 1 1 3
