Can global variables define arrays in php?

Global variables in PHP can define arrays, but it is best to avoid this practice. Using global variables in PHP is often considered a bad practice because it destroys the encapsulation and maintainability of the code. Global variables may be modified by multiple code blocks at the same time, resulting in immeasurable results. When using a large number of global variables, the code is difficult to maintain and understand. The scope of variables should be limited to an appropriate scope as much as possible to improve the code's readability. Maintainability and reusability.

The operating system for this tutorial: Windows 10 system, PHP8.1.3 version, Dell G3 computer.

In PHP, the scope of a variable (that is, the scope of code that can access the variable) can be local (local) or global. Local variables can only be used within a specific block of code (such as a function or class), while global variables can be used throughout the PHP script. For example, we can define a global variable, modify it within a function, and use it elsewhere outside that function.

However, using global variables in PHP is often considered a bad practice because it breaks the encapsulation and maintainability of the code. Global variables may be modified by multiple code blocks at the same time, leading to immeasurable results. When we use a large number of global variables, the code becomes difficult to maintain and understand.

In PHP, we can use the keyword global to access global variables inside a function. For example, if we define a global array called $myArray at the top of the script and use it inside the function, we can use the following code:

$myArray = array(1, 2, 3);
  
function myFunction(){
    global $myArray;
    // 在这里使用$myArray变量
}

What needs to be noted here is that modifying the global array inside the function The value of may have unexpected effects on other parts of the script. Therefore, when we need to use a global array, it is best to only read the value of the array inside the function instead of modifying it.

In general, although you can use global variables to access arrays in PHP, it is best to avoid this approach. If possible, we should limit the scope of variables to an appropriate scope as much as possible to improve the maintainability and reusability of the code.

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