php去掉一維陣列的鍵值的例項方法

在 PHP 中，陣列的每個元素都是由鍵值對（key-value）組成，通過元素的鍵名來訪問對應鍵的值。

提示：“索引”和“鍵名”指的是同一樣東西，“索引”多指陣列數字形式的下標。

有時候，我們需要去掉一維陣列的鍵值（value），只留下陣列的鍵名（key），這要怎麼做？

此時，就可以使用array_keys()函數了。

array_key() 函式可以獲取陣列中的部分或所有鍵名，語法格式如下：

array_keys($array [, $search_value = null [, $strict = false]])

引數說明如下：

$array：必選引數，為待操作的陣列；

$search_value：可選引數，如果引數為空，則函式會返回陣列中的所有鍵名，如果指定了該引數，則函式就只會返回值為 $search_value 的鍵名；

$strict：可選引數，判斷在搜尋的時候是否使用嚴格模式，$strict 預設為 false，也就是非嚴格模式，在搜尋時只比較型別，不比較型別，若將 $strict 設定為 true，也就是嚴格模式，在搜尋時同時比較值和型別，等價於===。

array_key() 函式會以陣列形式返回得到的陣列鍵名。

 '好二三四it網',        'url'   => 'https://www.how234.com/',        'title' => 'PHP學習教程',);$key=array_keys($array);var_dump($key);?>

可以看到，去掉了一維陣列的鍵值（value），只返回了一維陣列的鍵名（key）。

內容擴充套件：

1、使用unset()函式可以用於取消設定關聯陣列中的鍵及其值。

// 宣告關聯陣列$arr = array(    "1" => "加",    "2" => "減",    "3" => "乘",    "4" => "除");// 關聯陣列中刪除鍵1及其值unset($arr['1']);// 顯示陣列元素var_dump($arr);

2、使用array_diff_key()函式用於獲取一個或多個數組之間的差集。

此函式比較一個或多個數組之間的鍵並返回它們之間的差集。

// 宣告關聯陣列$arr = array(    "1" => "春",    "2" => "夏",    "3" => "秋",    "4" => "冬",);// 從關聯陣列中刪除鍵1及其值$result = array_diff_key($arr,    array_flip((array) ['1']));// 顯示陣列元素var_dump($result);

到此這篇關於php去掉一維陣列的鍵值的例項方法的文章就介紹到這了。

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