在PHP中選擇某些數據數組

Question

使用此行代碼時，我會得到以下輸出var_dump($ticket->find());如何在整個ALL對象中只訪問標識符？

我試過var_dump($ticket->find()->identifier);但它返回null。

array (size=2) 
    0 => 
    object(stdClass)[9] 
     public 'tid' => string '1' (length=1) 
     public 'uid' => string '22' (length=2) 
     public 'subject' => string 'iPhone 8' (length=8) 
     public 'issue' => string 'iPhone 8 screen replacement' (length=27) 
     public 'device' => string 'iPhone 8' (length=8) 
     public 'created' => string '2017-05-25 00:01:11' (length=19) 
     public 'identifier' => string '29cd54bf' (length=8) 
     public 'status' => string 'New' (length=3) 
     public 'tech' => string 'None' (length=4) 
    1 => 
    object(stdClass)[11] 
     public 'tid' => string '2' (length=1) 
     public 'uid' => string '22' (length=2) 
     public 'subject' => string 'iPhone 7' (length=8) 
     public 'issue' => string 'iPhone 7 screen replacement' (length=27) 
     public 'device' => string 'iPhone 7' (length=8) 
     public 'created' => string '2017-05-25 00:27:42' (length=19) 
     public 'identifier' => string 'b47f2c82' (length=8) 
     public 'status' => string 'New' (length=3) 
     public 'tech' => string 'None' (length=4) 

Answer 1

你可以使用array_map選擇您從find返回在array每個項目所需要的屬性：

$filteredFields = array_map(function ($item) { 
    // Return whatever properties you want here: 

    return [$item->tid, $item->$uid, $item->issue]; 
}, $ticket->find()); 

$filteredFields將arrays的array：

array(2) { 
    [0]=> array(3) { 
     [0]=> string(1) "1" 
     [1]=> string(2) "22" 
     [2]=> string(8) "iPhone 7" 
    } 
    [1]=> array(3) { 
     [0]=> string(1) "2" 
     [1]=> string(2) "22" 
     [2]=> string(8) "iPhone 7" 
    } 
} 

如果您只需要其中一個屬性，則可能更易於使用array_column：

$subjectFields = array_column($ticket->find(), "subject"); 

這將返回的東西，看起來像這樣：

array(2) { 
    [0]=> string(8) "iPhone 8" 
    [1]=> string(8) "iPhone 7" 
} 

您還可以得到一個關聯數組指示爲關鍵第三個參數使用的領域：

$subjectsByTid = array_column($ticket->find(), "subject", "tid"); 

這將返回：

array(2) { 
    ["1"]=> string(8) "iPhone 8" 
    ["2"]=> string(8) "iPhone 7" 
}