Question

我有一些我创建的代码，它应该可以查看字符串数组中是否存在某些内容。如果它不存在，我想删除该数组的元素。我认为我们使用unset执行此操作，但它似乎无法正常工作。心灵帮助？

echo '<br>size of $games before end-check: '.sizeof($games);
foreach ($games as $game) {
    $game_end_marker = "body = (game)#";
    $game_end_pos = strpos($game, $game_end_marker);
    if ($game_end_pos !== false) {
        echo "<br>end of game found";
    } 
    else {
        echo "<br>end of game not found. incomplete game";
        unset($game);
    }
}
echo '<br>size of $games after end-check: '.sizeof($games);

输出：

size of $games before end-check: 2  
end of game found  
end of game not found. incomplete game  
size of $games after end-check: 2

Answer 1

因为你取消了变量$ game的设置，而不是数组中的元素。试试这个：

echo '<br>size of $games before end-check: '.sizeof($games);
foreach ($games as $index => $game) {
    $game_end_marker = "body = (game)#";
    $game_end_pos = strpos($game, $game_end_marker);
    if ($game_end_pos !== false) {
        echo "<br>end of game found";
    } 
    else {
        echo "<br>end of game not found. incomplete game";
        unset($games[$index]);
    }
}
echo '<br>size of $games after end-check: '.sizeof($games);

Answer 2

你必须取消游戏指数。

foreach ($games as $key => $value) {
  // all your logic here, performed on $value
  unset($games[$key]);
}

Answer 3

这仅仅取消了对元素的本地引用。你需要直接引用数组。

foreach($games as $key => $game)
    unset($games[$key]);

Answer 4

这不起作用：foreach创建一个新变量，复制旧变量。取消设置它将对原始值无效。同样，将其作为参考也不会起作用，因为只会删除参考。

最好的方法是使用array_filter：

$games = array_filter($games, function($game) {
    $game_end_marker = "body = (game)#";
    $game_end_pos = strpos($game, $game_end_marker);

    if ($game_end_pos !== false) {
        echo "<br>end of game found";
        return true;
    } 
    else {
        echo "<br>end of game not found. incomplete game";
        return false;
    }
});

这使用PHP 5.3中引入的匿名函数语法。如果函数返回true，则保留元素;如果它返回false，则删除该元素。

Answer 5

您也可以参考：

foreach($games as &$game) {
    unset($game);
}

通过这种方式，您还可以更改$game（例如$game .= " blah";）并修改原始数组。

Answer 6

您可以将array_splice与递增增长的索引变量结合使用，以从数组中删除当前项：

$index = 0;
foreach ($games as $game) {
    $game_end_marker = "body = (game)#";
    $game_end_pos = strpos($game, $game_end_marker);
    if ($game_end_pos !== false) {
        echo "<br>end of game found";
    } 
    else {
        echo "<br>end of game not found. incomplete game";
        array_splice($games, $index, 1);
    }
$index++;
}

如果找不到，则从数组中删除元素

6 个答案: