How to remove duplicate data from an array in php (two methods)

As one of the most popular programming languages ​​at present, PHP language is widely used in Web development, meeting the needs of Web developers for powerful functions, easy learning and use, and efficient development. In PHP development, we often encounter problems that require deduplication. This article will focus on the topic of "Removing duplicate data instances from arrays in PHP" and introduce two deduplication methods for reference.

1. Use the array_unique function

The array_unique() function is a function provided by PHP for deduplication. Its function is to remove duplicate elements in the array and return the deduplicated array. .

The sample code is as follows:

<?php
$oldArr = array("apple", "orange", "banana", "apple", "banana");
$newArr = array_unique($oldArr);
print_r($newArr);
?>

The output result is:

Array
(
    [0] => apple
    [1] => orange
    [2] => banana
)

In the above example, $oldArr is the array to be deduplicated, and $newArr is the new array after deduplication. . After deduplication through the array_unique() function, the output result is an array of three elements, namely "apple", "orange" and "banana".

2. Use the loop method

In addition to using the array_unique() function, you can also remove duplicates through a loop. The specific implementation idea is: traverse each element in the array, and compare the traversed element with all subsequent elements. If a duplicate element appears later, delete the element from the original array.

The sample code is as follows:

<?php
$oldArr = array("apple", "orange", "banana", "apple", "banana");
for($i=0; $i<count($oldArr)-1; $i++){
    for($j=$i+1; $j<count($oldArr); $j++){
        if($oldArr[$i] == $oldArr[$j]){
            array_splice($oldArr, $j, 1);
            $j--;
        }
    }
}
print_r($oldArr);
?>

The output result is:

Array
(
    [0] => apple
    [1] => orange
    [2] => banana
)

In the above example, $oldArr is the array to be deduplicated. Each element in the array is traversed through a double loop, and the following elements are compared in turn to see if they are duplicates. If there are duplicates, delete them until the deletion is complete and the array is output.

Summary

This article introduces two PHP methods for removing duplicate data from arrays, namely the array_unique() function and the loop method. The specific method to use depends on the actual needs. It is recommended to choose the appropriate method according to the actual situation. At the same time, you also need to pay attention to the relevant knowledge and skills of PHP array deduplication to improve development efficiency and code quality as much as possible.

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