Question

我有一个对象数组，例如：

Array
(
    [0] => Array
        (
            [Id] => 1
            [Name] => Toy Car
            [Category] => Toys
            [Price] => 2.99
            [OnSale] => false
        )
    ...
)

但我希望他们按类别分组，然后按OnSale分组。

到目前为止，我已经能够按类别分组：

$result = array();
foreach ($data as $element) {
    $result[$element['Category']][] = $element;
}

但我不确定如何嵌套另一个foreach或者按类别对它们进行递归分组。任何帮助表示赞赏！

Answer 1

你的意思是：

$result = array();
foreach ($data as $element) {
    $result[$element['Category']][$element['OnSale']][] = $element;
}

编辑：抱歉，[和]所有问题......

Answer 2

你很亲密！您只需要添加要分组的第二个键。

$byCategoryAndSale = [];
foreach ($inventory as $item) {
    $byCategoryAndSale[$item['Category']][$item['OnSale']][] = $item;
}

注意使用布尔值作为数组键将等于1和0，这可能会让人感到困惑。

以下是一个完整的例子：

<?php
    $inventory = [
        [
            'Id' => 1,
            'Name' => 'Toy Car',
            'Category' => 'Toys',
            'Price' => 2.99,
            'OnSale' => false
        ],
        [
            'Id' => 2,
            'Name' => 'Another Toy',
            'Category' => 'Toys',
            'Price' => 1.99,
            'OnSale' => false
        ],
        [
            'Id' => 3,
            'Name' => 'Hamburger',
            'Category' => 'Not Toys',
            'Price' => 5.99,
            'OnSale' => false
        ],
        [
            'Id' => 4,
            'Name' => 'Last Toy',
            'Category' => 'Toys',
            'Price' => 50.99,
            'OnSale' => true
        ]
    ];

    $byCategoryAndSale = [];
    foreach ($inventory as $item) {
        $byCategoryAndSale[$item['Category']][$item['OnSale']][] = $item;
    }

    print_r($byCategoryAndSale);
?>

哪个收益率：

PS C:\> php test.php

(    
    [Toys] => Array
        (
            [0] => Array
                (
                    [0] => Array
                        (
                            [Id] => 1
                            [Name] => Toy Car
                            [Category] => Toys
                            [Price] => 2.99
                            [OnSale] =>
                        )

                    [1] => Array
                        (
                            [Id] => 2
                            [Name] => Another Toy
                            [Category] => Toys
                            [Price] => 1.99
                            [OnSale] =>
                        )

                )

            [1] => Array
                (
                    [0] => Array
                        (
                            [Id] => 4
                            [Name] => Last Toy
                            [Category] => Toys
                            [Price] => 50.99
                            [OnSale] => 1
                        )

                )

        )

    [Not Toys] => Array
        (
            [0] => Array
                (
                    [0] => Array
                        (
                            [Id] => 3
                            [Name] => Hamburger
                            [Category] => Not Toys
                            [Price] => 5.99
                            [OnSale] =>
                        )

                )

        )

)

在多个键上递归分组数组

2 个答案: