从PHP中的多维数组中删除重复数组

Question

如何从这个数组中过滤重复的值？

实际上，对于country和city，数据是相同的-除了总体发生变化之外。

如何删除包含更高人口的阵列？

$arr = array

(

    "100" => array(

        array(

            "country" => 'France',

            "city" => 'Paris',

            "population" => '1800000',

        ),

        array(

            "country" => 'France',

            "city" => 'Paris',

            "population" => '2000000',

        ),

        array(

            "country" => 'France',

            "city" => 'Toulouse',

            "population" => '500000',

        ),

    )

    "101" => array(

        array(

            "country" => 'Russia',

            "city" => 'Moscow',

            "population" => '144000000',

        )

    )

);

因此，所需的输出应为：

$arr = array

(

    "100" => array(

        array(

            "country" => 'France',

            "city" => 'Paris',

            "population" => '1800000'

        ),

        array(

            "country" => 'France',

            "city" => 'Toulouse',

            "population" => '500000'

        ),

    )

    "101" => array(

        array(

            "country" => 'Russia',

            "city" => 'Moscow',

            "population" => '144000000',

        )

    )

);

这是我尝试的：

$temp_array = [];

foreach ($array as &$v) {

    if (!isset($temp_array[$v['country']] && $temp_array[$v['city']]))

        $temp_array[$v[$key]] =& $v;

    }

$array = array_values($temp_array);

return $array;

Answer 1

您可以首先使用array_reduce过滤较低的人口（使用国家和城市的组合作为关键字）。然后将它们炸开并使用该最小值重置数组：foreach($arr as $k => &$ar) {    $temp = array_reduce($ar, function ($carry, $item) {        $key = $item["country"] . "###" . $item["city"];        $carry[$key] = (isset($carry[$key]) && $item["population"] > $carry[$key]) ?  $carry[$key] : $item["population"];        return $carry;    }, []);    $ar = [];    foreach($temp as $k => $val) {        list($country, $city) = explode("###", $k);        $ar[] = array("country" => $country, "city" => $city, "population" => $val);    }}直播示例：3lv4编辑：您可以使用array_filter，而不是foreach循环，以避免应对：$ar = array_filter($ar, function ($item) use ($mins) {    $key = $item["country"] . "###" . $item["city"];    return $mins[$key] == $item["population"]; });

Answer 2

我做了两个嵌套循环，第一个嵌套子数组包含一个特定键（例如100和101）的所有内容。接下来，我遍历数据，并保留一个包含两个级别的临时数组，第一个级别将国家作为关键，第二个级别将城市作为跟踪最低人口的关键。完成上述操作后，我将遍历临时数组以正确的格式获取国家，城市和人口，并将其附加到新数组中。然后，我用以前的数组替换这个新获取的结果。<?php$arr = array(&nbsp; &nbsp; "100" => array(&nbsp; &nbsp; &nbsp; &nbsp; array(&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; "country" => 'France',&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; "city" => 'Paris',&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; "population" => '1800000',&nbsp; &nbsp; &nbsp; &nbsp; ),&nbsp; &nbsp; &nbsp; &nbsp; array(&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; "country" => 'France',&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; "city" => 'Paris',&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; "population" => '2000000',&nbsp; &nbsp; &nbsp; &nbsp; ),&nbsp; &nbsp; &nbsp; &nbsp; array(&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; "country" => 'France',&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; "city" => 'Toulouse',&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; "population" => '500000',&nbsp; &nbsp; &nbsp; &nbsp; ),&nbsp; &nbsp; ),&nbsp; &nbsp; "101" => array(&nbsp; &nbsp; &nbsp; &nbsp; array(&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; "country" => 'Russia',&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; "city" => 'Moscow',&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; "population" => '144000000',&nbsp; &nbsp; &nbsp; &nbsp; )&nbsp; &nbsp; ));foreach($arr as $key=>$subarr) {&nbsp; &nbsp; $tmp = array();&nbsp; &nbsp; foreach($subarr as $v) {&nbsp; &nbsp; &nbsp; &nbsp; $country = $v['country'];&nbsp; &nbsp; &nbsp; &nbsp; $city = $v['city'];&nbsp; &nbsp; &nbsp; &nbsp; $population = $v['population'];&nbsp; &nbsp; &nbsp; &nbsp; if(isset($tmp[$country])) {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; if(isset($tmp[$country][$city])) {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; if($tmp[$country][$city] > $population) {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; $tmp[$country][$city] = $population;&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; }&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; } else {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; $tmp[$country][$city] = $population;&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; }&nbsp; &nbsp; &nbsp; &nbsp; } else {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; $tmp[$country] = array();&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; $tmp[$country][$city] = $population;&nbsp; &nbsp; &nbsp; &nbsp; }&nbsp; &nbsp; }&nbsp; &nbsp; $res = array();&nbsp; &nbsp; &nbsp; &nbsp; foreach($tmp as $country=>$cities) {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; foreach($cities as $city=>$population) {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; $res[] = array('country'=>$country,'city'=>$city,'population'=>$population);&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; }&nbsp; &nbsp; &nbsp; &nbsp; }&nbsp; &nbsp; $arr[$key] = $res;}print_r($arr);