What potential pitfalls should be considered when summarizing data from arrays in PHP?

When summarizing data from arrays in PHP, potential pitfalls to consider include ensuring that the array is not empty before trying to access its elements, handling non-existent keys or indexes to prevent errors, and being aware of the data types within the array to avoid unexpected results.

// Check if the array is not empty before summarizing data
if (!empty($array)) {
    // Loop through the array and summarize the data
    $sum = 0;
    foreach ($array as $value) {
        $sum += $value;
    }
    echo "Sum of array values: " . $sum;
} else {
    echo "Array is empty, cannot summarize data.";
}