Does PHP's Short-Circuit Evaluation Prevent Unnecessary Function Calls?

Does PHP's Short-Circuit Evaluation Minimize Unnecessary Operations?

PHP includes a mechanism known as short-circuit evaluation, which economizes evaluations by ending further checks when an earlier condition is false.

Consider the following code:

if (is_valid($string) && up_to_length($string) && file_exists($file)) 
{
    ......
}

If is_valid($string) evaluates to false, does PHP proceed to check the remaining conditions, such as up_to_length($string)?

PHP demonstrates laziness by executing the fewest comparisons necessary. If is_valid($string) returns false, PHP skips the remaining checks, as the overall condition is already determined as false.

To illustrate this, consider the following example:

function saySomething()
{
    echo 'hi!';
    return true;
}

if (false && saySomething())
{
    echo 'statement evaluated to true';
}

In this case, despite the saySomething() function being defined to echo 'hi!', the function is never called because the first condition, false, short-circuits the evaluation and prevents the interpreter from reaching the second condition.

The above is the detailed content of Does PHP's Short-Circuit Evaluation Prevent Unnecessary Function Calls?. For more information, please follow other related articles on the PHP Chinese website!