php - 从php中的数组中删除一个元素

Question

那好吧。我有一个这样定义的填充数组:

$subs = array();
for (...) {
    // extracting of variables $knowledgeLevel, $name, $short, $long
    $subs [] = array (
         'knowledgeLevel' => $knowledgeLevel,
         'name' => $name,
         'shortTheory' => $short,
         'longTheory' => $long
    );
}

然后我收到一个值 $kl ，我想最终从数组中删除 $subs element有 knowledgeLevel等于 $kl .我试过这样做:

foreach ( $subs as $subject ) {
    if ($subject['knowledgeLevel'] == $kl) {
        unset ($subject);
    }
}

所以

foreach ( $subs as $subject ) {
    if ($subject['knowledgeLevel'] == $kl) {
        unset ($subject['knowledgeLevel']);
        unset ($subject['name']);
        unset ($subject['shortTheory']);
        unset ($subject['longTheory']);
    }
}

但这些似乎不起作用。

Answer 1

In order to be able to directly modify array elements within the loop precede $value with &. In that case the value will be assigned by reference.

使用 &与 foreach ( $subs as &$subject )

foreach ( $subs as &$subject ) 
    if ( $subject['knowledgeLevel'] == $kl ) 
        unset ($subject);

或者试试这个:

This form will additionally assign the current element's key to the $key variable on each iteration.

foreach ( $subs as $key => $subject )
    if ( $subject['knowledgeLevel'] == $kl ) 
        unset( $subs[$key] );