There are several ways to deduplicate arrays in php

There are three common methods for deduplicating arrays in php: 1. The "array_unique()" function can remove duplicate values ​​​​in the array and return a new array; 2. Use a loop to delete duplicates, use for Or a foreach loop traverses the entire array to determine whether there are duplicates and delete them; 3. Use the "array_flip()" and "array_keys()" functions. The "array_flip()" function exchanges the keys and values ​​of the array, and "array_keys()" Get all key names.

Operating system for this tutorial: Windows 10 system, php8.1.3 version, Dell G3 computer.

There are three common ways to remove duplicates from arrays in php:

1. Use the array_unique() function

array_unique() function to remove duplicates from the array of repeated values ​​and returns a new array.

$array = array("a" => "apple", "b" => "banana", "c" => "apple");
$unique_array = array_unique($array);
print_r($unique_array);

The output result is:

Array
(
    [a] => apple
    [b] => banana
)

2. Use a loop to delete duplicate items

Use a for or foreach loop to traverse the entire array and judge Check if there are duplicates and delete them. This method works well for small arrays, but can be time-consuming for large arrays.

$array = array("a" => "apple", "b" => "banana", "c" => "apple");
foreach ($array as $key => $value) {
  $count = 0;
  foreach ($array as $k => $v) {
      if ($v == $value) {
          $count++;
          if ($count > 1) {
              unset($array[$k]);
          }
      }
  }
}
print_r($array);

Output:

Array
(
    [a] => apple
    [b] => banana
)

3. Use the array_flip() and array_keys() functions

Use the array_flip() function to convert the keys and values ​​of the array Swap, and use array_keys() to get all key names. Since the keys are unique, this effectively creates a set of results that does not contain duplicate items.

$array = array("a" => "apple", "b" => "banana", "c" => "apple");
$unique_array = array_flip(array_flip($array));
print_r($unique_array);

The output is:

Array
(
    [a] => apple
    [b] => banana
)

These methods are only a few methods that can achieve array deduplication. There are other methods such as using array_count_values(), array_reduce(), etc. For developers to master according to actual needs.

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