What does $ in php mean?

In PHP, the $ symbol represents a variable used to store various types of values, including numbers, strings, and objects. Variables are created by adding the $ sign to the variable name, and their type is determined by the assigned value. The variable scope is divided into local variables (inside the function) and global variables (outside the function) according to the declaration position, which can only be accessed within the function or the entire script respectively. Good variable naming practices include using meaningful names, avoiding reserved words, and using lowercase letters and underscores.

$ Meaning in PHP

In PHP, the $ symbol represents a variable. Variables are used to store values ​​such as numbers, strings, or objects.

Creating and using variables

To create a variable, use the $ symbol followed by the variable name. For example:

$name = "John Doe";
$age = 30;
$is_admin = true;

Now these variables can be used to store and retrieve values. For example:

echo $name; // 输出：John Doe
echo $age; // 输出：30

Variable type

Variables in PHP do not have explicit types. The type of a variable is determined by its value. If you assign a number to a variable, it becomes an integer type. If you assign a string, it becomes of type string and so on.

Variable scope

The scope of variables depends on whether they are declared inside or outside a function. Variables declared within a function are called local variables and can only be accessed within that function. Variables declared outside a function are called global variables and can be accessed throughout the script.

Good Practice

• Use meaningful variable names.
• Always initialize variables before using them.
• Try to use lowercase letters and underscores to name variables.
• Avoid using reserved words as variable names.

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