比较两个数组并以 github 样式呈现交集/差异

您可以简单地将数组组合为唯一项目（然后重新排序！然后，您可以循环新数组并检查原始 2 个数组中有哪些项目。

<?php

$src = ["apple", "cherry", "grape", "lemon", "orange", "strawberry"];
$dst = ["apple", "banana", "cherry", "orange", "pear"];

$combined_items = array_unique(array_merge($src, $dst));
sort($combined_items);

$new_array = [];

foreach($combined_items as $item){
    $item1 = in_array($item, $src) ? $item : null;
    $item2 = in_array($item, $dst) ? $item : null;
    $new_array[] = [$item1, $item2];
}

// $new_array will contain ["apple","apple"], [null, "banana"], etc.

对于不能保证输入数组按字母顺序排序并且可能包含重复项的情况，我想出了以下脚本。

1. 循环，直到至少一个阵列耗尽/消耗。如果您以后想使用这些原始数组，请复制或将我的代码片段包装在函数调用中。
2. 如果两个值相同，请将它们推送到结果数组中的同一行中。
3. 如果不完全相同，请确定哪些数组具有更接近的匹配值，并将该匹配之前的所有值作为单独的行推送到结果数组中。
4. 循环完成后，请确保将所有剩余值推送到结果数组中。

代码：（演示)

$src = ["apple", "cherry", "grape", "lemon", "orange", "strawberry", "cherry", "cherry"];
$dst = ["apple", "banana", "cherry", "orange", "pear", "cherry"];

$result = [];
while ($src && $dst) {
    if ($src[0] === $dst[0]) { // align identical values
        $result[] = [array_shift($src), array_shift($dst)];
        continue;
    }

    $earliestSrcMatch = array_search($src[0], $dst);
    $earliestDstMatch = array_search($dst[0], $src);

    if ($earliestSrcMatch === $earliestDstMatch) { //both false (not 0)
        $result[] = [array_shift($src), null];
        $result[] = [null, array_shift($dst)];
        continue;
    } elseif (
        $earliestDstMatch === false
        || (
            $earliestSrcMatch !== false
            && $earliestSrcMatch < $earliestDstMatch
        )
    ) {
        while ($dst && $src[0] !== $dst[0]) {
            $result[] = [null, array_shift($dst)];
        }
    } elseif (
        $earliestSrcMatch === false
        || $earliestSrcMatch > $earliestDstMatch
    ) {
        while ($src && $src[0] !== $dst[0]) {
            $result[] = [array_shift($src), null];
        }
    }
}
while ($src) {
    $result[] = [array_shift($src), null];
}
while ($dst) {
    $result[] = [null, array_shift($dst)];
}

要可视化为表格，请执行以下操作：

echo "<table border=1>
";
foreach ($result as $i => [$s, $d]) {
    printf(
        "<tr>
             <td>%d</td>
             <td>%s</td>
             <td>%s</td>
         </tr>\n",
         ++$i,
         $s,
         $d
    );
}
echo "</table>";

My take on @Snor's approach would be to set up two lookup arrays so that the performance benefits of key sorting and searching can be enjoyed. On relatively large arrays, iterated calls of may place unwanted drag on performance.in_array()

代码：（演示)

$src = array_combine($src, $src);
$dst = array_combine($dst, $dst);
$combined_items = $src + $dst;
ksort($combined_items);

$result = [];
foreach ($combined_items as $item) {
    $result[] = [
        $src[$item] ?? null,
        $dst[$item] ?? null
    ];
}