


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.
- 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'.
- 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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