如何刪除數組中的所有匹配值

Question

請仔細閱讀數組的輸入和輸出，並幫助我僅保留數組中的鍵並將匹配值留空。

輸入：

Array 
(
    [date] => 2016-02-23 
    [onday] => 1 
    [session] => Morning 
    [start_time] => 08:30:00 
    [cd_desc] => REGISTRATION 
    [end_time] => 09:00:00 
    [Name] => Fname Lname 
    [profile_Pic] => 145464959476.jpg 
) 
Array 
(
    [date] => 2016-02-23 
    [onday] => 1 
    [session] => Morning 
    [start_time] => 09:30:00 
    [cd_desc] => ON LABEL VS OFF LABEL (BOTOX) 
    [end_time] => 09:45:00 
    [Name] => Fname Lname 
    [profile_Pic] => 145464959476.jpg 
) 
Array 
(
    [date] => 2016-02-23 
    [onday] => 2 
    [session] => Morning 
    [start_time] => 09:00:00 
    [cd_desc] => INTRODUCTION 
    [end_time] => 09:15:00 
    [Name] => Fname Lname 
    [profile_Pic] => 145464959476.jpg 
) 

Array 
(
    [date] => 2016-02-20 
    [onday] => 2 
    [session] => Morning 
    [start_time] => 01:00:00 
    [cd_desc] => Lunch 
    [end_time] => 02:15:00 
    [Name] => Fname Lname 
    [profile_Pic] => 146.jpg 
) 

輸出：

date => 
    onday => 1 
    session => 
    start_time => 08:30:00 
    cd_desc => REGISTRATION 
    end_time => 09:00:00 
    Name => Fname Lname 
    profile_Pic => 145464959476.jpg 

    date => 
    onday => 
    session => 
    start_time => 09:30:00 
    cd_desc => ON LABEL VS OFF LABEL (BOTOX) 
    end_time => 09:45:00 
    Name => Fname Lname 
    profile_Pic => 145464959476.jpg 

    date => 
    onday => 2 
    session => 
    start_time => 09:00:00 
    cd_desc => INTRODUCTION 
    end_time => 09:15:00 
    Name => Fname Lname 
    profile_Pic => 145464959476.jpg 

    date => 
    onday => 
    session => 
    start_time => 01:00:00 
    cd_desc => Lunch 
    end_time => 02:15:00 
    Name => Fname Lname 
    profile_Pic => 146.jpg 

看date，onday和session同時顯示到每個循環

我要從中刪除所有匹配的值應該是空白數組，而不是鍵。我想用鑰匙

Answer 1

試試這個代碼，如果該項目的長度爲0，將不顯示

foreach($courseinfo['olinelist'] as $lists){ 
      foreach ($lists as $item){ 
       if (strlen($item) > 0) { 
        echo $item; 
       } 
      } 
     } 

Answer 2

$a=[...]; 
$blacklist=['onday','date']; 
$b=[]; 
foreach($a as $c) { 
    foreach($c as $key, $val) { 
    if(!in_array($key, $blacklist)){ 
     echo $key . " => " . $val . "\n"; 
    } else { 
     echo $key . " =>\n"; 
    } 
}