PHP array_flip () Remove array repeat elements _php tips

The method is as follows:
$arr = Array (...);//Suppose there are 10,000 elements of the arrays, which have duplicate elements.
$arr = Array_flip (Array_flip ($arr)); This allows you to delete duplicate elements.

What the hell is going on here? Take a look at the role of Array_flip (): Array_flip () is used to exchange keys and values for each element of an array, such as:
$arr 1 = Array ("Age" =>, "name" => "Happy Garden");
$arr 2 = array_flip ($arr 1); $arr 2 is the array (=> "age", "Happy Garden" => "name");
In an array of PHP, different elements are allowed to take the same value, but the same key name is not allowed to be used by different elements, such as:
$arr 1 = Array ("Age" =>, "name" => "Happy Garden", "age" => 20); "Age" => 20 will replace "age" => 30
$arr 1 = Array ("name" => "Happy Garden", "age" => 45);
Here $arr 1 is equal to the $ARR2.
Then we can see why Array_flip (Array_flip ($arr) can delete the duplicated elements in the array. First, the value in the $arr becomes the key name, because the value is duplicated, the duplicate value becomes the duplicate key name after the key name, and the PHP engine deletes the duplicate key name, leaving only the last one. Such as:
$arr 1 = Array ("Age" =>, "name" => "Happy Garden", "age" => 20);
$arr 1 = array_flip ($arr 1); $arr 1 became array ("Happy garden" => "name", => "age");
Then the key name of the $arr 1 and the value are also complex:
$arr 1 = array_flip ($arr 1);

The code above is written in a concise way: $arr 1 = array_flip (Array_flip ($arr 1));