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:
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();
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.
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:
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.
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