What is the function array_unique in PHP and how can it be used to solve the issue of checking for identical values in an array?

The issue of checking for identical values in an array can be solved using the `array_unique` function in PHP. This function removes duplicate values from an array, leaving only unique values. By applying `array_unique` to an array, you can easily check for identical values and eliminate any duplicates.

// Sample array with duplicate values
$array = [1, 2, 2, 3, 4, 4, 5];

// Remove duplicate values
$unique_array = array_unique($array);

// Check for identical values
if(count($array) != count($unique_array)) {
    echo "Array contains identical values.";
} else {
    echo "Array does not contain identical values.";
}