Question

我有这个PHP数组：

<?php 

$cities = [
    'amsterdam' => $amsterdam,
    'prague'    => $prague,
    'lisboa'    => $lisboa
];

$amsterdam = [
    65 => [
        'table'     => Object
        'something' => false,
        'data'      => [
            'foo'    => 'boo',
            'price'   => 100
        ]
    ],
    173 => [
        'table'     => Object
        'something' => false,
        'data'      => [
            'foo'    => 'hoo',
            'price'   => 2500
        ]
    ],
    ...
];

$prague    = [
    132 => [
        'table'     => Object
        'something' => false,
        'data'      => [
            'foo'    => 'boo',
            'price'   => 2100
        ]
    ],
    956 => [
        'table'     => Object
        'something' => false,
        'data'      => [
            'foo'    => 'hoo',
            'price'   => 2500
        ]
    ],
    ...
];

$lisboa    = [
    175 => [
        'table'     => Object
        'something' => false,
        'data'      => [
            'foo'    => 'boo',
            'price'   => 6500
        ]
    ],
    64 => [
        'table'     => Object
        'something' => false,
        'data'      => [
            'foo'    => 'hoo',
            'price'   => 20
        ]
    ],
    ...
];

?>

我需要按子数组值['data'] ['price']对其进行排序，因此输出如下所示：

<?php
    $cheapest_cities [
        'lisboa'    => $lisboa,    // because 64->data->price is 20
        'amsterdam' => $amsterdam, // beacuse 65->data->price is 100
        'prague'    => $prague     // bacause 132->data->price is 2100
    ];
?>

我尝试了几种usort组合，但是问题是，在我的示例中，我不知道子数组索引是什么（65、173、132、956、175、64）。

您是否知道如何排序？

数据来自数据库：

<?php

        $amsterdam  = $this->getTable()->where(['package_id' => [1,2,3]])->order('package_id')->fetchPairs('id');
        $lisboa     = $this->getTable()->where(['package_id' => [4,5]])->order('package_id')->fetchPairs('id');
        $prague     = $this->getTable()->where(['package_id' => [6]])->order('package_id')->fetchPairs('id');

        return [
            'amsterdam'     => $amsterdam,
            'lisboa'        => $lisboa,
            'prague'        => $prague,
        ];

?>

谢谢

Answer 1

请勿使用usort，因为它会删除您的密钥。使用uasort。

一个简单的想法：在uasort的回调函数中，您可以搜索商品的最小值，例如通过array_reduce。

array_reduce($city, function($carry, $item) {
    return $carry === 0 ? $item['data']['price'] : min($carry, $item['data']['price']);
}, 0);

此代码段获取城市数组的最小值。然后比较值应该很容易。

Full example：

function getMinimumPrice($cityArray) {
    return array_reduce($cityArray, function($carry, $item) {
        return $carry === 0 ? $item['data']['price'] : min($carry, $item['data']['price']);
    }, 0);
}

uasort($cities, function($city1, $city2) {
    $priceCity1 = getMinimumPrice($city1);
    $priceCity2 = getMinimumPrice($city2);

    return $priceCity1 <=> $priceCity2;
});

如何使用未知索引按子数组值对数组进行排序

1 个答案: