Опис

round(int|float $num, int $precision = 0, int|RoundingMode $mode = RoundingMode::HalfAwayFromZero): float

Returns the rounded value of num to specified precision (number of digits after the decimal point). precision can also be negative or zero (default).

Параметри

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 RoundingMode or one of the following constants to specify the mode in which rounding occurs.

Константи Опис

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.

However, please note that some newly added modes only exist in RoundingMode.

Константи	Опис
`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.

Значення, що повертаються

The value rounded to the given precision as a float.

Помилки/виключення

The function throws a ValueError if mode is invalid. Prior to PHP 8.4.0, an invalid mode would silently default to PHP_ROUND_HALF_UP.

Журнал змін

Версія	Опис
8.4.0	Four new rounding modes have been added.
8.4.0	Now throws a ValueError if `mode` is invalid.
8.0.0	`num` no longer accepts internal objects which support numeric conversion.

Приклади

Приклад #1 round() examples

<?php
var_dump(round(3.4));
var_dump(round(3.5));
var_dump(round(3.6));
var_dump(round(3.6, 0));
var_dump(round(5.045, 2));
var_dump(round(5.055, 2));
var_dump(round(345, -2));
var_dump(round(345, -3));
var_dump(round(678, -2));
var_dump(round(678, -3));
?>

Поданий вище приклад виведе:

float(3)
float(4)
float(4)
float(4)
float(5.05)
float(5.06)
float(300)
float(0)
float(700)
float(1000)

Приклад #2 How precision affects a float

<?php
$number = 135.79;

var_dump(round($number, 3));
var_dump(round($number, 2));
var_dump(round($number, 1));
var_dump(round($number, 0));
var_dump(round($number, -1));
var_dump(round($number, -2));
var_dump(round($number, -3));
?>

Поданий вище приклад виведе:

float(135.79)
float(135.79)
float(135.8)
float(136)
float(140)
float(100)
float(0)

Приклад #3 mode examples

<?php
echo 'Rounding modes with 9.5' . PHP_EOL;
var_dump(round(9.5, 0, PHP_ROUND_HALF_UP));
var_dump(round(9.5, 0, PHP_ROUND_HALF_DOWN));
var_dump(round(9.5, 0, PHP_ROUND_HALF_EVEN));
var_dump(round(9.5, 0, PHP_ROUND_HALF_ODD));

echo PHP_EOL;
echo 'Rounding modes with 8.5' . PHP_EOL;
var_dump(round(8.5, 0, PHP_ROUND_HALF_UP));
var_dump(round(8.5, 0, PHP_ROUND_HALF_DOWN));
var_dump(round(8.5, 0, PHP_ROUND_HALF_EVEN));
var_dump(round(8.5, 0, PHP_ROUND_HALF_ODD));
?>

Поданий вище приклад виведе:

Rounding modes with 9.5
float(10)
float(9)
float(10)
float(9)

Rounding modes with 8.5
float(9)
float(8)
float(8)
float(9)

Приклад #4 mode with precision examples

<?php
echo 'Using PHP_ROUND_HALF_UP with 1 decimal digit precision' . PHP_EOL;
var_dump(round( 1.55, 1, PHP_ROUND_HALF_UP));
var_dump(round(-1.55, 1, PHP_ROUND_HALF_UP));

echo PHP_EOL;
echo 'Using PHP_ROUND_HALF_DOWN with 1 decimal digit precision' . PHP_EOL;
var_dump(round( 1.55, 1, PHP_ROUND_HALF_DOWN));
var_dump(round(-1.55, 1, PHP_ROUND_HALF_DOWN));

echo PHP_EOL;
echo 'Using PHP_ROUND_HALF_EVEN with 1 decimal digit precision' . PHP_EOL;
var_dump(round( 1.55, 1, PHP_ROUND_HALF_EVEN));
var_dump(round(-1.55, 1, PHP_ROUND_HALF_EVEN));

echo PHP_EOL;
echo 'Using PHP_ROUND_HALF_ODD with 1 decimal digit precision' . PHP_EOL;
var_dump(round( 1.55, 1, PHP_ROUND_HALF_ODD));
var_dump(round(-1.55, 1, PHP_ROUND_HALF_ODD));
?>

Поданий вище приклад виведе:

Using PHP_ROUND_HALF_UP with 1 decimal digit precision
float(1.6)
float(-1.6)

Using PHP_ROUND_HALF_DOWN with 1 decimal digit precision
float(1.5)
float(-1.5)

Using PHP_ROUND_HALF_EVEN with 1 decimal digit precision
float(1.6)
float(-1.6)

Using PHP_ROUND_HALF_ODD with 1 decimal digit precision
float(1.5)
float(-1.5)

Приклад #5 Example of using RoundingMode

<?php
foreach (RoundingMode::cases() as $mode) {
    foreach ([
        8.5,
        9.5,
        -3.5,
    ] as $number) {
        printf("%-17s: %+.17g -> %+.17g\n", $mode->name, $number, round($number, 0, $mode));
    }
    echo "\n";
}
?>

Поданий вище приклад виведе:

HalfAwayFromZero : +8.5 -> +9
HalfAwayFromZero : +9.5 -> +10
HalfAwayFromZero : -3.5 -> -4

HalfTowardsZero  : +8.5 -> +8
HalfTowardsZero  : +9.5 -> +9
HalfTowardsZero  : -3.5 -> -3

HalfEven         : +8.5 -> +8
HalfEven         : +9.5 -> +10
HalfEven         : -3.5 -> -4

HalfOdd          : +8.5 -> +9
HalfOdd          : +9.5 -> +9
HalfOdd          : -3.5 -> -3

TowardsZero      : +8.5 -> +8
TowardsZero      : +9.5 -> +9
TowardsZero      : -3.5 -> -3

AwayFromZero     : +8.5 -> +9
AwayFromZero     : +9.5 -> +10
AwayFromZero     : -3.5 -> -4

NegativeInfinity : +8.5 -> +8
NegativeInfinity : +9.5 -> +9
NegativeInfinity : -3.5 -> -4

PositiveInfinity : +8.5 -> +9
PositiveInfinity : +9.5 -> +10
PositiveInfinity : -3.5 -> -3

Прогляньте також

ceil() - Округлює дріб в більшу сторону
floor() - Round fractions down
number_format() - Format a number with grouped thousands