How to remove duplicates from an array based on specific key-value pairs in PHP?

In PHP, use the array_unique() function to remove duplicates from an array based on specific key-value pairs. When calling the function, pass in the array as a parameter and select the sorting method as the second parameter. This function returns a new array in which duplicates have been removed based on the specified key-value pairs.

How to remove duplicates from an array based on specific key-value pairs in PHP

In PHP, use The array_unique() function removes duplicates from an array based on specific key-value pairs. This function receives an array as argument and returns a new array in which duplicates have been removed based on the specified key-value pairs.

Usage:

$array = [
    ['name' => 'John', 'age' => 30],
    ['name' => 'Mary', 'age' => 25],
    ['name' => 'John', 'age' => 30],
    ['name' => 'Bob', 'age' => 20],
];

$uniqueArray = array_unique($array, SORT_REGULAR);

print_r($uniqueArray);

Output:

Array
(
    [0] => Array
        (
            [name] => John
            [age] => 30
        )

    [1] => Array
        (
            [name] => Mary
            [age] => 25
        )

    [2] => Array
        (
            [name] => Bob
            [age] => 20
        )
)

As shown above, array_unique() According to Key-value pairs ['name', 'age'] Remove duplicates in the array.

Optional parameters:

array_unique() The second parameter of the function specifies how to compare array elements. The following options are available:

• SORT_REGULAR: Compare elements normally
• SORT_NUMERIC: Compare elements as numbers
• SORT_STRING: Compare Elements as strings
• SORT_LOCALE_STRING: Comparing elements as strings with a specific locale

Practical example:

Suppose you have the following array, which contains line items from different orders:

$orders = [
    ['id' => 1, 'item_id' => 1, 'quantity' => 2],
    ['id' => 2, 'item_id' => 2, 'quantity' => 1],
    ['id' => 3, 'item_id' => 1, 'quantity' => 3],
];

You can use the following code to sort the order based on the order item ID (item_id) and quantity (quantity) Remove duplicates:

$uniqueOrders = array_unique($orders, SORT_REGULAR);

This will create a new array $uniqueOrders with the item_id and quantity combination for each order item All are unique.

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