PHP in_array() 無法正常工作

Question

我在下面有一個if語句，用於檢查數組中是否存在值，如果不存在則將其添加到那里。 顯然，即使該值在數組中，它也會再次觸發它。

據我了解，它應該只顯示每個值的 1 個，因為它只會觸發 3 次，如下所示：

Digital Photography -> 0
Step by Step Macintosh Training -> 0
How to become a Powerful Speaker -> 0

代碼：

if (!in_array($unit['course_name'], $courseList)) {

  $courseList[$unit['course_name']]['name'] = $unit['course_name'];
  $courseList[$unit['course_name']]['seconds'] = 0;
  echo $courseList[$unit['course_name']]['name'] . ' -> ' . $courseList[$unit['course_name']]['seconds'];
  echo "<BR>";

}

但它輸出：

Digital Photography -> 0
Step by Step Macintosh Training -> 0
Step by Step Macintosh Training -> 0
Step by Step Macintosh Training -> 0
How to become a Powerful Speaker -> 0
How to become a Powerful Speaker -> 0

這是var_dump($unit) ：

array(8) { ["author_name"]=> string(10) "tuiuiu_dev" [0]=> string(10) "tuiuiu_dev" ["course_name"]=> string(19) "Digital Photography" [1]=> string(19) "Digital Photography" ["unit_id"]=> string(3) "181" [2]=> string(3) "181" ["unit_quantity"]=> string(1) "1" [3]=> string(1) "1" } 
array(8) { ["author_name"]=> string(15) "William Merussi" [0]=> string(15) "William Merussi" ["course_name"]=> string(31) "Step by Step Macintosh Training" [1]=> string(31) "Step by Step Macintosh Training" ["unit_id"]=> string(3) "227" [2]=> string(3) "227" ["unit_quantity"]=> string(1) "1" [3]=> string(1) "1" } 
array(8) { ["author_name"]=> string(15) "William Merussi" [0]=> string(15) "William Merussi" ["course_name"]=> string(31) "Step by Step Macintosh Training" [1]=> string(31) "Step by Step Macintosh Training" ["unit_id"]=> string(3) "231" [2]=> string(3) "231" ["unit_quantity"]=> string(1) "1" [3]=> string(1) "1" } 
array(8) { ["author_name"]=> string(15) "William Merussi" [0]=> string(15) "William Merussi" ["course_name"]=> string(31) "Step by Step Macintosh Training" [1]=> string(31) "Step by Step Macintosh Training" ["unit_id"]=> string(3) "233" [2]=> string(3) "233" ["unit_quantity"]=> string(1) "1" [3]=> string(1) "1" } 
array(8) { ["author_name"]=> string(10) "tuiuiu_dev" [0]=> string(10) "tuiuiu_dev" ["course_name"]=> string(32) "How to become a Powerful Speaker" [1]=> string(32) "How to become a Powerful Speaker" ["unit_id"]=> string(4) "1080" [2]=> string(4) "1080" ["unit_quantity"]=> string(1) "1" [3]=> string(1) "1" } 
array(8) { ["author_name"]=> string(10) "tuiuiu_dev" [0]=> string(10) "tuiuiu_dev" ["course_name"]=> string(32) "How to become a Powerful Speaker" [1]=> string(32) "How to become a Powerful Speaker" ["unit_id"]=> string(4) "1084" [2]=> string(4) "1084" ["unit_quantity"]=> string(1) "1" [3]=> string(1) "1" } 

感謝您的幫助！

Answer 1

in_array()方法檢查數組值，而不是鍵。 從您的示例中，我可以看到您有一個包含name和seconds字段的數組作為值。 我認為您想檢查該 id 是否存在於您的數組中。

所以if ：

if (!in_array($unit['course_name'], $courseList)) {

應該像這樣改變：

if (!isset($courseList[$unit['course_name']])) {

這樣您就可以檢查$unit['course_name']是否在您的數組中作為鍵。

Answer 2

如果你有一個只有值的數組，你應該使用in_array函數作為這個例子：

$array = array("A", "B", "C");
in_array($string, $array) ? "found" : "not found";

否則，如果你有一個帶鍵的數組，你應該使用isset函數作為這個例子：

$array = array("A" => "Result A", "B" => "Result B", "C" => "Result C");
isset($array[$string]) ? "found" : "not found";