intdiv

(PHP 7, PHP 8)

intdiv — 对除法结果取整

说明

intdiv(int $num1, int $num2): int

返回 num1 除以 num2 商数的整数部分。

参数

num1: 被除数。
num2: 除数。

返回值

num1 除以 num2 的商，对该商取整。

错误／异常

如果 num2 是 0，将抛出 DivisionByZeroError 异常。如果 num1 是 PHP_INT_MIN 并且 num2 是 -1，将抛出 ArithmeticError 异常.

示例

示例 #1 intdiv() 的一些示例

<?php
var_dump(intdiv(3, 2));
var_dump(intdiv(-3, 2));
var_dump(intdiv(3, -2));
var_dump(intdiv(-3, -2));
var_dump(intdiv(PHP_INT_MAX, PHP_INT_MAX));
var_dump(intdiv(PHP_INT_MIN, PHP_INT_MIN));
var_dump(intdiv(PHP_INT_MIN, -1));
var_dump(intdiv(1, 0));
?>

int(1)
int(-1)
int(-1)
int(1)
int(1)
int(1)

Fatal error: Uncaught ArithmeticError: Division of PHP_INT_MIN by -1 is not an integer in %s on line 8
Fatal error: Uncaught DivisionByZeroError: Division by zero in %s on line 9

参见

/——浮点除法
%——整数取模
fmod() - 返回除法的浮点数余数——浮点数取模

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down

AmeenRoss ¶

9 years ago

This does indeed seem to be equal to intdiv:

<?php
function intdiv_1($a, $b){
    return ($a - $a % $b) / $b;
}
?>

However, this isn't:

<?php
function intdiv_2($a, $b){
    return floor($a / $b);
}
?>

Consider an example where either of the parameters is negative:
<?php
$param1 = -10;
$param2 = 3;
print_r([
    'modulus' => intdiv_1($param1, $param2),
    'floor' => intdiv_2($param1, $param2),
]);

/**
 * Array
 * (
 *     [modulus] => -3
 *     [floor] => -4
 * )
 */
?>

down

oittaa ¶

2 years ago

Python style integer division, where the result is always rounded towards minus infinity.

1 // 2 is 0
(-1) // 2 is -1
1 // (-2) is -1
(-1) // (-2) is 0

<?php
function intdiv_py(int $num1, int $num2): int{
    if ($num1 < 0 xor $num2 < 0){
        $num1 = abs($num1);
        $num2 = abs($num2);
        $remainder = $num1 % $num2;
        return $remainder ? -1 -($num1 - $remainder) / $num2 : -$num1 / $num2;
    }
    return intdiv($num1, $num2);
}

var_dump(intdiv_py(1, 2)); // 0
var_dump(intdiv_py(-1, 2)); // -1
var_dump(intdiv_py(1, -2)); // -1
var_dump(intdiv_py(-1, -2)); // 0
?>

down

-2

sree dot millu at gmail dot com ¶

5 years ago

@AmeenRoss 
This does NOT  seem to be equal to intdiv:

<?php
function intdiv_1($a, $b){
    return ($a - $a % $b) / $b;
}
 ?>

See this example code
<?php 

$x = 5.6;
$y = 1.4 ;

echo intdiv($x,$y);
    
    echo "\n";
    
function intdiv_1($a, $b){
    return ($a - $a % $b) / $b;
}    

echo intdiv_1($x,$y);
?>

//Output
5
4