The static variable mechanism of PHP functions allows variables to retain their values between function calls, thereby achieving the following functionality: Preserving state between function calls. Avoid creating duplicate variables. Simplify the code.
Static variable mechanism of PHP function
Introduction
Static variable is a A special variable scope that exists only inside a function and retains its value each time the function is called. This is different from regular variables, which are reset after each function call.
Syntax
To declare a static variable, just precede the variable with the static
keyword, as shown below:
function foo() { static $counter = 0; $counter++; echo $counter; }
Practical Case
Suppose we want to create a function that prints an incrementing counter every time it is called. Using static variables, we can easily achieve this:
function getCounter() { static $counter = 0; $counter++; return $counter; } echo getCounter(); // 输出 1 echo getCounter(); // 输出 2 echo getCounter(); // 输出 3
Difference from non-static variables
Advantages
Note
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