PHP 中四舍五入到最接近的五的倍数

Question

I want a php function which returns 55 when calling it with 52.

I've tried the round() function:

echo round(94, -1); // 90

It returns 90 but I want 95 .

Thanks.

Answer 1

This can be accomplished in a number of ways, depending on your preferred rounding convention:

1. Round to the next multiple of 5, exclude the current number

Behaviour: 50 outputs 55, 52 outputs 55

function roundUpToAny($n,$x=5) {
    return round(($n+$x/2)/$x)*$x;
}

2. Round to the nearest multiple of 5, include the current number

Behaviour: 50 outputs 50, 52 outputs 55, 50.25 outputs 50

function roundUpToAny($n,$x=5) {
    return (round($n)%$x === 0) ? round($n) : round(($n+$x/2)/$x)*$x;
}

3. Round up to an integer, then to the nearest multiple of 5

Behaviour: 50 outputs 50, 52 outputs 55, 50.25 outputs 55

function roundUpToAny($n,$x=5) {
    return (ceil($n)%$x === 0) ? ceil($n) : round(($n+$x/2)/$x)*$x;
}

Answer 2

1. Divide by 5
2. round() (or ceil() if you want to round up always )
3. Multiply by 5.

The value 5 (the resolution / granularity) can be anything — replaced it in both step 1 and 3

So in summary:

    $rounded_number = ceil( $initial_number / 5 ) * 5

Answer 3

Round down:

$x = floor($x/5) * 5;

Round up:

$x = ceil($x/5) * 5;

Round to closest (up or down):

$x = round($x/5) * 5;

Answer 4

   echo $value - ($value % 5);

我知道这是一个老问题，但恕我直言，使用模数运算符是最好的方法，而且比公认的答案要优雅得多。

Answer 5

Try this little function I wrote.

function ceilFive($number) {
    $div = floor($number / 5);
    $mod = $number % 5;

    If ($mod > 0) $add = 5;
    Else $add = 0;

    return $div * 5 + $add;
}

echo ceilFive(52);

Answer 6

From Gears library

MathType::roundStep(50, 5); // 50
MathType::roundStep(52, 5); // 50
MathType::roundStep(53, 5); // 55

MathType::floorStep(50, 5); // 50
MathType::floorStep(52, 5); // 50
MathType::floorStep(53, 5); // 50

MathType::ceilStep(50, 5); // 50
MathType::ceilStep(52, 5); // 55
MathType::ceilStep(53, 5); // 55

Source:

public static function roundStep($value, int $step = 1)
{
    return round($value / $step) * $step;
}

public static function floorStep($value, int $step = 1)
{
    return floor($value / $step) * $step;
}

public static function ceilStep($value, int $step = 1)
{
    return ceil($value / $step) * $step;
}

Answer 7

Here is my version of Musthafa's function. This one is more complex but it has support for Float numbers as well as Integers. The number to be rounded can also be in a string.

/**
 * @desc This function will round up a number to the nearest rounding number specified.
 * @param $n (Integer || Float) Required -> The original number. Ex. $n = 5.7;
 * @param $x (Integer) Optional -> The nearest number to round up to. The default value is 5. Ex. $x = 3;
 * @return (Integer) The original number rounded up to the nearest rounding number.
 */
function rounduptoany ($n, $x = 5) {

  //If the original number is an integer and is a multiple of 
  //the "nearest rounding number", return it without change.
  if ((intval($n) == $n) && (!is_float(intval($n) / $x))) {

    return intval($n);
  }
  //If the original number is a float or if this integer is 
  //not a multiple of the "nearest rounding number", do the 
  //rounding up.
  else {

    return round(($n + $x / 2) / $x) * $x;
  }
}

I tried the functions from Knight , Musthafa and even the suggestion from Praesagus . They don't have support for Float numbers and the solutions from Musthafa's & Praesagus do not work correctly in some numbers. Try the following test numbers and do the comparison yourself:

$x= 5;

$n= 200;       // D = 200     K = 200     M = 200     P = 205
$n= 205;       // D = 205     K = 205     M = 205     P = 210
$n= 200.50;    // D = 205     K = 200     M = 200.5   P = 205.5
$n= '210.50';  // D = 215     K = 210     M = 210.5   P = 215.5
$n= 201;       // D = 205     K = 205     M = 200     P = 205
$n= 202;       // D = 205     K = 205     M = 200     P = 205
$n= 203;       // D = 205     K = 205     M = 205     P = 205

** D = DrupalFever K = Knight M = Musthafa P = Praesagus

Answer 8

乘以 2，四舍五入到 -1，再除以 2。

Answer 9

I do it like this:

private function roundUpToAny(int $n, $x = 9)
{
    return (floor($n / 10) * 10) + $x;
}

Tests:

assert($this->roundUpToAny(0, 9) == 9);
assert($this->roundUpToAny(1, 9) == 9);
assert($this->roundUpToAny(2, 9) == 9);
assert($this->roundUpToAny(3, 9) == 9);
assert($this->roundUpToAny(4, 9) == 9);
assert($this->roundUpToAny(5, 9) == 9);
assert($this->roundUpToAny(6, 9) == 9);
assert($this->roundUpToAny(7, 9) == 9);
assert($this->roundUpToAny(8, 9) == 9);
assert($this->roundUpToAny(9, 9) == 9);
assert($this->roundUpToAny(10, 9) == 19);
assert($this->roundUpToAny(11, 9) == 19);
assert($this->roundUpToAny(12, 9) == 19);
assert($this->roundUpToAny(13, 9) == 19);
assert($this->roundUpToAny(14, 9) == 19);
assert($this->roundUpToAny(15, 9) == 19);
assert($this->roundUpToAny(16, 9) == 19);
assert($this->roundUpToAny(17, 9) == 19);
assert($this->roundUpToAny(18, 9) == 19);
assert($this->roundUpToAny(19, 9) == 19);

Answer 10

function round_up($n, $x = 5) {
  $rem = $n % $x;
  if ($rem < 3)
     return $n - $rem;
  else
     return $n - $rem + $x;
}

Answer 11

I just wrote this function in 20 min, based on many results I found here and there, I don't know why it works or how it works!! :D

I was mainly interested in converting currency numbers from this 151431.1 LBP to 150000.0 LBP. (151431.1 LBP == ~100 USD) which works perfectly so far, however I tried to make it somehow compatible with other currencies and numbers, but not sure if it works fine!!

/**
 * Example:
 * Input = 151431.1 >> return = 150000.0
 * Input = 17204.13 >> return = 17000.0
 * Input = 2358.533 >> return = 2350.0
 * Input = 129.2421 >> return = 125.0
 * Input = 12.16434 >> return = 10.0
 *
 * @param     $value
 * @param int $modBase
 *
 * @return  float
 */
private function currenciesBeautifier($value, int $modBase = 5)
{
    // round the value to the nearest
    $roundedValue = round($value);

    // count the number of digits before the dot
    $count = strlen((int)str_replace('.', '', $roundedValue));

    // remove 3 to get how many zeros to add the mod base
    $numberOfZeros = $count - 3;

    // add the zeros to the mod base
    $mod = str_pad($modBase, $numberOfZeros + 1, '0', STR_PAD_RIGHT);

    // do the magic
    return $roundedValue - ($roundedValue % $mod);
}

Feel free to modify it and fix it if there's anything wrong

Answer 12

Probably you can also consider this one liner. It's faster! Works for $num >= 0 and $factor > 0 .

$num = 52;
$factor = 55;
$roundedNum = $num + $factor - 1 - ($num + $factor - 1) % $factor;