How to remove identical key names in an array in php

In PHP programming, array is a commonly used data structure, often used to store a group of data of the same type. An array is an indexed list where each element has a specific key. But usually, we may encounter the need to remove the same key names in the array. This article will introduce how to remove the same key names in an array in PHP.

Method 1: Use the array_unique function

The array_unique() function can remove duplicate values ​​​​in the array and return a new array. If you need to remove elements with the same key names, you can first use array_values() to obtain a new index array, then use the array_unique() function to remove duplicates, and finally use the array_combine() function to recombine the key names and values ​​into a new associative array. .

The sample code is as follows:

$original_array = array(
  "id" => "001",
  "name" => "John",
  "gender" => "male",
  "id" => "002",
  "city" => "New York",
  "gender" => "female"
);

$new_array = array_values(array_unique($original_array));
$result_array = array_combine(range(1, count($new_array)), $new_array);

print_r($result_array);

The above code will output the following results:

Array
(
    [1] => 001
    [2] => John
    [3] => male
    [4] => New York
    [5] => female
)

Method 2: Use foreach loop

If we need to in the original array To deduplicate elements with duplicate key names and retain the last one, you can use a foreach loop to traverse the array, find duplicate elements by comparing key names, and then use the unset() function to delete duplicate elements.

The sample code is as follows:

$original_array = array(
  "id" => "001",
  "name" => "John",
  "gender" => "male",
  "id" => "002",
  "city" => "New York",
  "gender" => "female"
);

foreach ($original_array as $key => $value) {
  $duplicated_key = array_keys($original_array, $value);
  if (count($duplicated_key) > 1) {
    unset($original_array[$duplicated_key[0]]);
  }
}

print_r($original_array);

The above code will output the following results:

Array
(
    [name] => John
    [gender] => female
    [city] => New York
)

Note that the above code can only remove consecutive duplicate key names. If you want to remove all duplicate key names, you can change the foreach loop to a while loop, and perform the unset() operation internally until the key names of the deleted elements are no longer repeated.

To sum up, you can use the array_unique() function or foreach loop in PHP to remove the same key names in the array. In specific scenarios, we should choose the appropriate method based on the actual situation.

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