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获取另一个已知元素的数组元素?

arrays php

qadenza · 技术社区 · 6 年前

Array
(
    [0] => Array
        (
            [what] => b4
            [map] => 74,76,77,83
        )

    [1] => Array
        (
            [what] => b2
            [map] => 53,82
        )

    [2] => Array
        (
            [what] => b1
            [map] => 36
        )
 )

abc('b4');

function abc($what){
    $map = // element `map` where `what` = $what;
}

所以我需要 map 哪里 what 等于 $what ;

例如-if 什么? 是 b4 结果应该是 74,76,77,83 等等。

我该怎么做?

6 回复 | 直到 6 年前

Jeff 6 年前

用 array_search() 和 array_column() 你可以找到匹配的 $map 在一行中:

<?php

$array = Array
(
    Array
        (
            "what" => "b4",
            "map" => "74,76,77,83"
        ),
   Array
        (
            "what" => "b2",
            "map" => "53,82"
        ),
    Array
        (
            "what" => "b1",
            "map" => "36"
        )
 );

function abc($array, $what) {
   return $array[array_search($what, array_column($array, 'what'))]['map'];
}   

echo abc($array, "b4");

函数的构造和解释如下:

function abc($array /* the complete input array */, $what /* the search string */) {
   // get the key of the sub-array that has $what in column 'what':
   $key = array_search($what, array_column($array, 'what'));
   // use that key to get 'map' on index $key
   return $array[$key]['map'];
}

在这里可以找到一把工作的小提琴: https://3v4l.org/0NpcX

Nigel Ren 6 年前

如果要定期访问数据, what 是唯一的,然后使用 array_column() 以第三个参数作为要用作键的列。然后您的阵列就可以轻松访问 什么 在这个答案中没有回路受到伤害…

$array = Array
(
    Array
    (
        "what" => "b4",
        "map" => "74,76,77,83"
        ),
    Array
    (
        "what" => "b2",
        "map" => "53,82"
        ),
    Array
    (
        "what" => "b1",
        "map" => "36"
        )
    );

$array = array_column($array, null, "what");

echo $array['b4']['map'];

给予。。。

74,76,77,83

arkascha 6 年前

我认为在数组中“行走”很容易阅读和理解:

<?php
$map = [
    [
        'what' => "b4",
        'map' => "74,76,77,83"
    ],
    [
            'what' => "b2",
            'map' => "53,82"
    ],
    [
            'what' => "b1",
            'map' => "36"
    ]
];

function lookupWhatInMap(&$map, $what) {
    array_walk($map, function($entry, $key) use ($what) {
        if ($entry['what'] == $what) {
            print_r($entry['map']);
        }
    });
}

lookupWhatInMap($map, "b4");

Ibu 6 年前

你所要做的就是循环浏览你的地图并比较数值。

function abc($what){
    $map = [...];
    foreach($map as $item) {
        if (isset($item[$what]) ) {
            return $item["map"];
        }
    }
    return false;
}

The fourth bird 6 年前

如果只需要数组中的1个值,则可以使用foreach和返回语句,其中存在匹配项:

$a = [
    [
        "what" => "b4",
        "map" => "74,76,77,83"
    ],
    [
        "what" => "b2",
        "map" => "53,82"
    ],
    [
        "what" => "b1",
        "map" => "36"
    ]
];
function abc($what, $arrays)
{
    foreach ($arrays as $array) {
        if ($array['what'] === $what) {
            return $array['map'];
        }
    }
    return false;
}

echo(abc('b4', $a)); // 74,76,77,83

Demo

Alex 6 年前

https://ideone.com/V9WNNx

$arr[] = [
            'what' => 'b4',
            'map' => '74,76,77,83'
        ];
$arr[] = [
            'what' => 'b2',
            'map' => '53,82'
        ];
$arr[] = [
            'what' => 'b1',
            'map' => '36'
        ];

echo abc('b4', $arr);

function abc($what, $arr){
    $map = null;
    $idx = array_search($what, array_column($arr, 'what'));
    if ($idx !== false) {
        $map = $arr[$idx]['map'];
    }
    return $map;
}