无法对数组进行切片-我需要将数组一分为二 - Cannot slice array - I need to split an array in half

我有一个数组，如下所示。我想把它切成两半，并从两半创建两个新的数组。然而，如果我使用array_slice，它总是返回null。。。我不明白为什么。

array
  'pic' => 
    array
      0 => string '740' (length=3)
      1 => string '741' (length=3)
      2 => string '742' (length=3)
      3 => string '748' (length=3)
  'alt' => 
    array
      0 => string '' (length=0)
      1 => string '' (length=0)
      2 => string 'Test caption 1' (length=14)
      3 => string 'Test caption 2' (length=14)

我需要的数组应该保留键，只是切成两半，所以我有两个互补的一半。例如，上半场应该看起来像：

array
  'pic' => 
    array
      0 => string '740' (length=3)
      1 => string '741' (length=3)
  'alt' => 
    array
      0 => string '' (length=0)
      1 => string '' (length=0)

下半场：

array
  'pic' => 
    array
      0 => string '742' (length=3)
      1 => string '748' (length=3)
  'alt' => 
    array
      0 => string 'Test caption 1' (length=14)
      1 => string 'Test caption 2' (length=14)

感谢

ps-对Mike来说，这就是我用来制作阵列的东西，实际上它是由其他阵列本身构建的：

$lodgepics = get_field('accommodation_rooms');
$featuredpics = get_field('featured_pics');
$showcasepics = array();
foreach ($featuredpics as $featuredpic) {
    if (isset($featuredpic['featured_pic'])&&!empty($featuredpic['featured_pic'])) $showcasepics[pic][] = $featuredpic['featured_pic'];
    if (isset($featuredpic['featured_alt'])) $showcasepics[alt][] = $featuredpic['featured_alt'];
else $showcasepics[alt][] = '';
}
foreach ($lodgepics as $lodgepic) {
    if(isset($lodgepic['accommodation_roomphoto'])&&!empty($lodgepic['accommodation_roomphoto'])) $showcasepics[pic][] = $lodgepic['accommodation_roomphoto'];
    if(isset($lodgepic['accommodation_roomname'])&&!empty($lodgepic['accommodation_roomname'])) $showcasepics[alt][] = $lodgepic['accommodation_roomname'];
    else $showcasepics[alt][] = '';
}

这些实际上是数组的数组。主数组是一个关联数组，因此您需要循环遍历该数组的所有键才能获得切片：

$slice1 = array();
$slice2 = array();
foreach ($array as $key => $value)
{
    $slice1[$key] = array_slice($array[$key], ...);
    $slice2[$key] = array_slice($array[$key], ...);
}

我很难理解是否需要做你提议的事情，如果是我，我不会使用你的结构填充数组，我会创建这样的数组：

array
  0 => 
    array
      'pic' => string '740' (length=3)
      'alt' => string '' (length=0)
  1 => 
    array
      'pic' => string '741' (length=3)
      'alt' => string '' (length=0)
  2 => 
    array
      'pic' => string '742' (length=3)
      'alt' => string 'Test Caption 1' (length=0)
  3 => 
    array
      'pic' => string '748' (length=3)
      'alt' => string 'Test Caption 2' (length=0)

此数组结构将图像属性保持在一起，而不是将它们分开。

tomtheman5有80%，但省略了需要传递以获得正确切片的array_slice调用的偏移量和长度参数。然而，他确实提出了一个很好的观点，如果你坚持你的数组结构，如果你在每个"pic"answers"alt"数组中没有匹配的元素，你可能会遇到问题。如果这不是一个问题，那么考虑以下片段：

$slice1 = array();
$slice2 = array();    
foreach ($array as $key => $value) {
    $arrayCount = count($array[$key]);
    $arrayHalfCount = ($arrayCount / 2);
    $slice1[$key] = array_slice($array[$key], 0, $arrayHalfCount);
    $slice2[$key] = array_slice($array[$key], $arrayHalfCount);
}

--编辑--

$lodgepics = get_field('accommodation_rooms');
$featuredpics = get_field('featured_pics');
$showcasepics = array();
foreach ($featuredpics as $featuredpic) {
    if ((isset($featuredpic['featured_pic'])) && (!empty($featuredpic['featured_pic']))) {
        $currentPic['pic'] = $featuredpic['featured_pic'];
        $currentPic['alt'] = (isset($featuredpic['featured_alt'])) ? $featuredpic['featured_alt'] : ''; 
        $showcasepics[] = $currentPic;
}
}
foreach ($lodgepics as $lodgepic) {
    if ((isset($lodgepic['accommodation_roomphoto'])) && (!empty($lodgepic['accommodation_roomphoto']))) {
        $currentPic['pic'] = $lodgepic['accommodation_roomphoto'];    
        $currentPic['alt'] = (isset($lodgepic['accommodation_roomname'])) ? $lodgepic['accommodation_roomname'] : '';
        $showcasepics[] = $currentPic;
}
}
$showcasepicsCount = count($showcasepics);
$showcasepicsHalfCount = ($showcasepicsCount / 2);
$slice1 = array_slice($showcasepics, 0, $showcasepicsHalfCount);
$slice2 = array_slice($showcasepics, $showcasepicsHalfCount);

array_chunk--将数组拆分为块

$array1 = array("1" => "green", "2" => "brown", "3" => "blue", "4" => "black");
$array2 = array("5" => "yellow","6" => "orange","7"=> "violet","8"=> "white");
$arraylength1   = ceil(count($array1)/2);
$res1           = array_chunk($array1,$arraylength1);
$arraylength2   = ceil(count($array2)/2);
$res2           = array_chunk($array2,$arraylength2);
echo "<pre>";
print_r($res1);
print_r($res2);
echo "</pre>";
exit;

试试这个。