Practical case: Use end() to handle the last order status in the order system

In the development of order systems, handling order status is a very critical part. Each order will experience different states during the life cycle, such as "to be paid", "paid", "to be shipped", "to be shipped", "to be shipped", "to be completed", etc. For an order system, how to efficiently track and modify the last order status is one of the problems developers need to solve. PHP's end() function can be very useful when processing arrays, especially when we need to get the last element of the array.

This article will combine actual cases to explore in-depth how to use the end() function in PHP to handle the last order status in the order system.

1. Overview of end() function

The end() function is used in PHP to point the internal pointer of the array to the last element and return the value of that element. Similar functions include reset() (pointing the pointer to the first element) and current() (geting the element pointed to by the current pointer). The end() function is often used in scenarios where the last element in an array is needed, especially in an order system, we often need to perform corresponding operations based on the last order status.

grammar:

 end($array);

• $array : Target array.

This function returns the value of the last element in the array, and moves the array pointer to the last element.

2. Practical case: Order status processing

Suppose we have an order system, each order has multiple statuses. The status of an order is usually stored as an array. For example, an order may experience the following states: "Pending payment" , "Paid" , "Shipped" , "Completed" .

 $orderStatus = [
    "To be paid",
    "Paid",
    "Shipped",
    "Completed"
];

Now, we need to use the end() function to get the last state of the order and make corresponding operations based on this state.

Code example:

 <?php
$orderStatus = [
    "To be paid",
    "Paid",
    "Shipped",
    "Completed"
];

// Get the last order status
$lastStatus = end($orderStatus);

// Output the last order status
echo "The last order status is: " . $lastStatus;

// Perform different operations according to the last state
if ($lastStatus === "Completed") {
    echo "订单Completed，Can finish the order。";
} elseif ($lastStatus === "Shipped") {
    echo "订单Shipped，Waiting for users to receive the goods。";
} elseif ($lastStatus === "Paid") {
    echo "订单Paid，Ready to ship。";
} elseif ($lastStatus === "To be paid") {
    echo "订单To be paid，Please remind the user to pay。";
} else {
    echo "Unknown order status。";
}
?>

In the above code, end($orderStatus) gets and returns the last state value in the array, which is "completed" . Next, we use conditional statements to perform different operations according to the last state of the order.

result:

 The last order status is: Completed
订单Completed，Can finish the order。

3. Application in actual projects

In actual projects, the order system may obtain the order status information from the database, and the returned data is usually an array or object. In this case, we can still use the end() function to get the last order status.

Suppose we get the status of an order from the database, similar to the following example:

 $orderStatusFromDb = [
    "To be paid",
    "Paid",
    "Shipped",
    "Completed"
];

// Assume an array of order statuses obtained from the database
$lastStatusFromDb = end($orderStatusFromDb);

// Perform the corresponding operation
switch ($lastStatusFromDb) {
    case "Completed":
        // Finish the order
        break;
    case "Shipped":
        // Shipping operation
        break;
    case "Paid":
        // Shipping preparation
        break;
    case "To be paid":
        // Remind users to pay
        break;
    default:
        // Error handling
        break;
}

Here, end($orderStatusFromDb) can still quickly obtain the last order status and execute different business logic according to the status.

4. Things to note

When using the end() function, you must pay attention to the following points:

1. Array pointer problem : After calling end() , the internal pointer of the array will point to the last element. If you need to manipulate the array again, remember to use reset() to reset the pointer to the starting position of the array.

2. Processing of empty arrays : If the array is empty, end() returns false . When using it, you should make sure that the array is not empty and avoid unnecessary errors.

 $orderStatus = [];
$lastStatus = end($orderStatus);

if ($lastStatus === false) {
    echo "No order status available。";
}