比较php中的多维和一维数组 [英] Comparing Multi and single dimensional arrays in php

问题描述

我是刚接触php的新手.我想从数组中获取不同维度的内容

I am new to php just playing with some array. I Want to get following things from the array which are of different dimensional

以下是多维数组

$a = array(
array(
    'productsid' => 90,
    'CouponID' => 50
),
array(
    'productsid' => 80,
    'CouponID' => 95
),
  array(
    'productsid' => 80,
    'CouponID' => 95
));

以下是一维数组:

$b = array(80,90,95);

我只想将数组的productid索引与一维数组进行比较，并希望获取与其相等的数据.

I want to compare only the productsid index of the array with the single dimensional array and wants to fetch the data which is equal to it.

我尝试了以下循环进行打印，但是它仅给出productid的值，但是我需要完整的数组.但是只能通过将Productid与第二个数组进行比较.

I Have tried the following loop to print but it only gives the values of the productsid only but I want that full array. But only by comparing the Productid with the second array.

for ($i = 0; $i < 3; $i++) {
foreach ($a[$i] as $key => $value) {
    foreach ($b as $c) {
        if ($value == $c) {
            echo $value .'<br>';

        }
    }
} }

推荐答案

看起来您正在寻找 in_array() :

Looks like you're looking for in_array():

$result = array();
foreach($a as $item)
    if(in_array($item['productsid'], $b))
        $result []= $item;

或者，以一种更简洁(但不太易懂的IMO)的方式:

or, in a more concise (but less readable IMO) way:

$result = array_filter($a, function($item) use($b) {
    return in_array($item['productsid'], $b);
});

对于您的测试数据来说无关紧要，但是如果您的数组很大和/或此循环将运行多次，则可以通过将查找数组转换为哈希表并使用 O(1)键查找，而不是线性数组搜索:

For your test data it's doesn't matter much, but if your arrays are big and/or this loop is going to run many times, you can achieve better performance by converting the lookup array into a hash table and using O(1) key lookup instead of linear array search:

$bs = array_flip($b);
$result = array_filter($a, function($item) use($bs) {
    return isset($bs[$item['productsid']]);
});

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