What are the common errors or mistakes that can lead to duplicate values in PHP arrays?

Common errors or mistakes that can lead to duplicate values in PHP arrays include not checking for existing values before adding new ones, inadvertently using the same key for different values, or accidentally overwriting existing values. To prevent duplicate values, you can use functions like `in_array()` to check if a value already exists in the array before adding it. Example PHP code snippet: 

// Initialize an array
$myArray = array();

// Add values to the array, checking for duplicates
function addValueToArray($value, &$array) {
    if (!in_array($value, $array)) {
        $array[] = $value;
    }
}

// Example usage
addValueToArray("apple", $myArray);
addValueToArray("banana", $myArray);
addValueToArray("apple", $myArray); // This value will not be added again

// Print the array to see the unique values
print_r($myArray);

Keywords

PHP arrays duplicate values array_unique array_merge array_intersect

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