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    intdiv

    (PHP 7, PHP 8)

    intdiv — 整数値の除算

    説明

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

    num1 を num2 で割った整数商を返します。

    パラメータ

    num1

    割られる数。

    num2

    num1 を割る数。

    戻り値

    num1 を num2 で割った整数商。

    エラー / 例外

    num2 が 0 の場合、DivisionByZeroError 例外がスローされます。num1 が PHP_INT_MIN で num2 が -1 の場合、 ArithmeticError 例外がスローされます。

    例

    例1 intdiv() の例

    <?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

    参考

    • / - 浮動小数点数値の除算
    • % - 整数値の剰余
    • fmod() - 引数で除算をした際の剰余を返す - 浮動小数点数値の剰余

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    User Contributed Notes 3 notes

    up
    43
    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
    * )
    */
    ?>
    up
    6
    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
    ?>
    up
    -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
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