What is the use of the get_defined_constants () function in PHP

This article mainly introduces what is the use of the get_defined_constants() function in PHP. It has certain reference value. Interested friends can refer to it. I hope you will gain a lot after reading this article. Let Xiaobian take you to understand it together.

get_defined_constants()

Returns an associative array of all constants, where keys are constant names and values are constant values.

define("MY_CONSTANT", 1);

print_r(get_defined_constants(true));

// array(

// ……

// [user] => array(

// [MY_CONSTANT] => 1

// )

// )

This function will output all constants, because the return content is a lot, so use...... It means that there are many system or extension defined constants, and the constants we define ourselves in the code will all enter the key name [user].

This function takes one argument, and when it is true, lets the function return a multidimensional array of keys classified in the first dimension, constants and their values in the second dimension. The default is false and returns a one-dimensional array of constant names as keys and their values as keys.

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