How to remove duplicate key values ​​​​in a one-dimensional array in php

PHP is an open source server-side scripting language widely used for web development. When we are developing a project, we may need to remove duplicate key values ​​​​in a one-dimensional array. This article will introduce how to use PHP language to remove duplicate key values ​​​​in one-dimensional arrays.

1. Use PHP built-in function array_unique()

Use PHP built-in function array_unique() to remove duplicate elements from a one-dimensional array. The function of this function is to return a new array that only contains unique elements in the original array. The code is as follows:

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

The output result is:

Array ( [a] => apple [b] => banana )

In the above code, the original array is $array, containing 3 elements: 'a' => 'apple', 'b ' => 'banana', 'c' => 'apple', where the value 'apple' corresponding to the key 'c' is repeated. The new array $new_array returned by the array_unique() function only contains unique elements, that is, 'a' => 'apple' and 'b' => 'banana'.

2. Using a loop to traverse the array

In addition to the array_unique() function introduced above, we can also use a loop to traverse the array to remove duplicate key values ​​​​in the one-dimensional array. The specific steps are as follows:

• Declare a new array to store unique elements;
• Loop through the original array and add unique elements to the new array;
• Use the PHP built-in function in_array() to determine whether the current element already exists in the new array. If it does not exist, add it to the new array.

The code is as follows:

$array = array("a" => "apple", "b" => "banana", "c" => "apple");
$new_array = array();

foreach($array as $value) {
    if(!in_array($value, $new_array)) {
        $new_array[] = $value;
    }
}

print_r($new_array);

The output result is:

Array ( [0] => apple [1] => banana )

In the above code, the original array is $array, containing 3 elements: 'a' => 'apple', 'b' => 'banana', 'c' => 'apple', where the value 'apple' corresponding to the key 'c' is repeated. By looping through the array, we remove duplicate elements, and the returned new array $new_array only contains non-duplicate elements, namely 'apple' and 'banana'.

To sum up, we can use PHP's built-in function array_unique() or loop through the array to remove duplicate key values ​​​​in the one-dimensional array. In actual development, the appropriate method can be selected according to project needs.

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