How many bytes does a php variable occupy?

In many programming languages, the size of variables is a very important topic. PHP is no exception. Different variables may occupy different numbers of bytes in PHP, which may cause some problems for programmers when writing code. How to determine the size of a variable? This is the question that this article will explore.

The first thing you need to know is that in PHP, the size of a variable is determined by the variable type and the size of its value. The basic data types supported in the PHP language include integers, floating point numbers, Boolean values, strings, and arrays. The memory usage of these data types is as follows:

1. Integer (integer): In a 32-bit system, an integer occupies 4 bytes. In a 64-bit system, an integer occupies 8 words. Festival.
2. Floating point type (float): A floating point number occupies 4 bytes in 32-bit systems and 8 bytes in 64-bit systems.
3. Boolean value (boolean): A Boolean value occupies 1 byte in memory and has only two values: true and false.
4. String (string): The memory usage of a string depends on its length and the character set used. In the UTF-8 character set, a string may occupy 1 to 4 bytes, while in the UTF-16 character set it occupies 2 to 4 bytes.
5. Array (array): The number of bytes occupied by each element in the array depends on the element type and how it is stored. For example, an array containing 3 integers will occupy 12 bytes (4 bytes/integer * 3 integers).

In addition to basic data types, PHP also supports composite types such as objects and resources. In addition, there is a special data type in PHP - NULL. The NULL type has only one value, null, which does not occupy any memory space.

It should be noted that as the PHP version is upgraded, the memory size occupied by variables may change. For example, prior to PHP 7.2, an integer occupied 8 bytes on 32-bit systems. But in PHP 7.2 and later versions, an integer only requires 4 bytes on 32-bit systems. Therefore, programmers should always pay attention to changes in PHP version updates to ensure that their programs have optimal performance when running.

To summarize, the memory usage of PHP variables is determined by the variable type and the size of its value. When writing code, you need to understand the memory usage of each data type to ensure that the program runs efficiently.

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