从多维数组中的元素中获取最大值? [英] Get the maximum value from an element in a multidimensional array?

问题描述

我正在尝试为多维数组中的特定键选择最大值.我在找到"有问题的关键时遇到了麻烦......

I'm trying to select the maximum value for a particular key in a multidimensional array. I'm having trouble "getting to" the key in question...

所以，数组(比我在这里发布的要长得多)

So, the array (which is much more lengthy than what I'm posting here)

[0] => stdClass Object
    (
        [id] => 70
        [cust] => 4
        [dnum] => 1
        [upper] => Array
            (
                [0] => 66
            )

    )
[1] => stdClass Object
    (
        [id] => 43
        [cust] => 42
        [dnum] => 2
        [upper] => Array
            (
                [0] => 77
            )

    )
[2] => stdClass Object
    (
        [id] => 12
        [cust] => 3
        [dnum] => 0
        [upper] => Array
            (
                [0] => 99
            )

    )

我试图在整个数组中找到最大的dnum"值，所以在这个例子中，$max = 2.我知道 max 函数允许我这样做，但我不知道如何引用 dnum 元素而不将整个内容放在 foreach 循环中，如果我这样做，那么 max 将不是要使用的函数，对吗?

I'm trying to find the maximum "dnum" value across the entire array, so in this example, $max = 2. I know that the max function allows me to do this, but I'm not sure how to reference the dnum element without putting the whole thing in a foreach loop, and if I do that, then max wouldn't be the function to use, right?

所以，我不能完全做到这一点:

So, I can't exactly do this:

$max = max($myarray[]->dnum);

有没有办法让我无需重新创建整个数组就可以做到这一点?

Is there a way for me to do this without having to recreate the entire array?

推荐答案

$max = 0;
foreach($array as $obj)
{
    if($obj->dnum > $max)
    {
        $max = $obj->dnum;
    }
}

如果您的最高数字不是负数(负数、空数组和 0 将最大值返回为 0)，该函数将正常工作.

That function would work correctly if your highest number is not negative (negatives, empty arrays, and 0s will return the max as 0).

因为您使用的是可以具有自定义属性/结构的对象，所以我不相信您真的可以使用任何预定义"函数来获取它.也可以只使用 foreach 循环.

Because you are using an object, which can have custom properties/structures, I don't believe there are really any 'predefined' functions you can use to get it. Might as well just use a foreach loop.

您真的无法摆脱 foreach 循环，因为即使是内部函数也使用 foreach 循环，它只是在幕后.

You really can't get away from a foreach loop, as even internal functions use a foreach loop, it is just behind the scenes.

另一个解决方案是

$numbers = array();
foreach($array as $obj)
{
    $numbers[] = $obj->dnum;
}
$max = max($numbers);

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