Null Coalesce operator in PHP7: How to simplify the conditional judgment of the code?

Null Coalesce operator in PHP7: How to simplify the conditional judgment of the code?

During the development process, we often need to perform conditional judgments on variables to determine whether they have a value or whether they are null. The traditional way is to use if statements or ternary operators to perform conditional judgments, but this way of writing seems lengthy and complicated in some cases. Fortunately, the Null Coalesce operator (??) was introduced in PHP7, which can help us simplify the way we write code and improve development efficiency.

The Null Coalesce operator is a concise way to determine whether a value is null. Its syntax is as follows:

$variable = $value ?? $default;

In the above code, $value is the variable we need to judge, and $default is the default value we specify. If $value exists and is not null, assign the value of $value to $variable; otherwise, assign the value of $default to $variable.

The following uses several specific examples to demonstrate the use of the Null Coalesce operator.

First, suppose we have a variable $user. We hope that during output, if the user's name exists, the name will be printed, otherwise "Unknown" will be printed. Using the traditional way, we might write like this:

if(isset($user['name'])) {
    echo $user['name'];
} else {
    echo "Unknown";
}

But using the Null Coalesce operator, this can be simplified to:

echo $user['name'] ?? "Unknown";

Next, we consider a more complex example. Suppose we have an array $products, which contains the prices of several products. We need to calculate the total price of all products and print the total price. The traditional way may be written like this:

$totalPrice = 0;
foreach ($products as $product) {
    if(isset($product['price'])) {
        $totalPrice += $product['price'];
    }
}
echo $totalPrice;

And using the Null Coalesce operator, it can be simplified to:

$totalPrice = 0;
foreach ($products as $product) {
    $totalPrice += $product['price'] ?? 0;
}
echo $totalPrice;

In the above code, if $product['price'] exists and does not If it is null, $product['price'] will be added to $totalPrice; otherwise, 0 will be added to $totalPrice by default. In this way, we no longer need to use if statements to make conditional judgments, and the code is more concise and clear.

The Null Coalesce operator can be used not only for arrays, but also for objects and other complex data structures. It can greatly simplify the conditional judgment in our code, reduce the amount of code and improve development efficiency.

It should be noted that when using the Null Coalesce operator, you need to clearly understand the priority of the operator. If multiple Null Coalesce operators are used in an expression, the order of calculation needs to be determined based on the precedence of the operators.

In summary, the Null Coalesce operator is a very useful feature in PHP7, which can help us simplify conditional judgments and default value settings in the code. By rationally using the Null Coalesce operator, we can write more concise and readable code and improve development efficiency.

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