How to get different values ​​from an array in php

In PHP development, we often encounter the need to deduplicate an array. At this time, we need to take out the different values ​​​​in the array to facilitate subsequent data processing. The following will introduce several common methods of extracting different values ​​​​from an array.

Method 1: Use the array_unique function

PHP provides the array_unique function, which can remove duplicate values ​​from the array and return a new array. The implementation principle of this function is to traverse the original array and save each value as a key name into a new array. Since the key name cannot be repeated, only one value will be retained in the new array.

The following is a sample code using the array_unique function:

$arr = array(1, 2, 3, 2, 4, 3);
$unique_arr = array_unique($arr);
print_r($unique_arr);

The output result is as follows:

Array
(
    [0] => 1
    [1] => 2
    [2] => 3
    [4] => 4
)

As you can see, using the array_unique function, a new value is obtained by removing duplicate values. array.

Method 2: Use the array_flip function

In addition to using the array_unique function, we can also use the array_flip function to remove duplicates. The principle of this function is to interchange the keys and values ​​in the array. If there are duplicate values, the later values ​​will overwrite the previous values. Then swap the keys and values ​​back to get the deduplicated array.

The following is a sample code using the array_flip function:

$arr = array(1, 2, 3, 2, 4, 3);
$unique_arr = array_flip(array_flip($arr));
print_r($unique_arr);

The output result is also a deduplicated array:

Array
(
    [0] => 1
    [1] => 2
    [2] => 3
    [4] => 4
)

Method 3: Use loop traversal

In addition to using PHP built-in functions, we can also manually implement loop traversal to remove duplicates. The specific implementation method is to traverse the original array, compare each value with the value that has been traversed before, if the same value already exists, skip it, otherwise add it to the new array.

The following is a sample code using loop traversal:

$arr = array(1, 2, 3, 2, 4, 3);
$unique_arr = array();

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

print_r($unique_arr);

The output result is also a deduplicated array:

Array
(
    [0] => 1
    [1] => 2
    [2] => 3
    [4] => 4
)

Method 4: Use the array_diff function

In addition to the above methods, we can also use the array_diff function to remove duplicates. This function takes two arrays as arguments and will return the values ​​in the first array that are not in the second array. Therefore, we can pass the original array and an empty array to the function to get the deduplicated array.

The following is a sample code using the array_diff function:

$arr = array(1, 2, 3, 2, 4, 3);
$empty_arr = array();
$unique_arr = array_diff($arr, $empty_arr);

print_r($unique_arr);

The output result is also a deduplicated array:

Array
(
    [0] => 1
    [1] => 2
    [2] => 3
    [4] => 4
)

Summary:

That’s it Several common ways to retrieve different values ​​from an array. Although the implementation principles of these methods are different, they can all effectively remove duplicates. In PHP development, we can choose the appropriate method to handle different values ​​in the array according to the specific situation.

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