How to define a global array in php

In PHP, if we need to access an array anywhere in the program, then we can define a global array. Next, we will detail how to define global arrays in PHP.

1. What is a global array

In PHP, a global array refers to an array that can be defined outside a function and accessed inside the function. The definition of global arrays is usually placed at the beginning of a PHP program.

2. How to define a global array

The following is how to define a global array in PHP:

1. Use the $GLOBALS array

In PHP, $GLOBALS is a system-built-in array that represents global variables in the current script. In this array, the variable name is the key and the variable value is the value. If we need to define a global array, we can regard the array as a container of global variables and put the array that needs to be shared into it.

The sample code is as follows:

// 定义全局数组
$GLOBALS['my_global_array'] = array('one', 'two', 'three');

// 在函数内部访问全局变量
function my_func() {
    print_r($GLOBALS['my_global_array']);
}

my_func();

2. Use the abbreviated form of the $GLOBALS array

The above code can be abbreviated as:

// 定义全局数组
$my_global_array = array('one', 'two', 'three');

// 在函数内部访问全局变量
function my_func() {
    global $my_global_array;
    print_r($my_global_array);
}

my_func();

Inside the function, we use the keyword global to indicate that the variable is a global variable for easy access.

3. Using static variables

Static variables in PHP refer to variables defined inside a function and whose life cycle is the same as the entire program running cycle. Define a static variable inside the function and assign the defined array to it to achieve the purpose of the global array.

The sample code is as follows:

// 定义全局数组
function my_func() {
    static $my_global_array = array('one', 'two', 'three');
    print_r($my_global_array);
}

my_func();

In this code, $my_global_array is defined as a static variable, but its life cycle is the entire program running cycle, so it can be regarded as a global array.

3. How to access the global array

We can access the global array by using the $GLOBALS or global keyword inside the function.

The sample code is as follows:

// 定义全局数组
$my_global_array = array('one', 'two', 'three');

// 在函数内部访问全局变量
function my_func() {
    global $my_global_array;
    print_r($my_global_array);
}

my_func();

In the above code, we use the global keyword to declare that $my_global_array is a global variable for easy access within the function.

4. Notes

When using global arrays, we need to pay attention to the following points:

1. The definition of global arrays should be concentrated at the beginning or end of the program as much as possible Other easy to find locations.
2. It is not recommended to modify the global array inside the function, because this will make the code unpredictable and difficult to maintain.
3. Access to the global array should be minimized to reduce program complexity and improve code readability and maintainability.
4. Summary

Defining a global array in PHP is a flexible and powerful function that can easily share data. Overall, when using global arrays, attention should be paid to the readability and maintainability of the code to avoid unnecessary errors.

The above is the detailed content of How to define a global array in php. For more information, please follow other related articles on the PHP Chinese website!