PHP Basic Learning process

1. Basic knowledge

A. NOTES:

<? PHP // This is a single-line comment # This is also a single-line comment /* This is a multiline comment block that spans multiple lines of */?>

B. Case sensitive:

In PHP, all user-defined functions, classes, and keywords (such as if, else, Echo, and so on) are not case sensitive.

In PHP, however, all variables are case-sensitive.

C. Variables:

<? PHP $x=5;   // Defining Variables $y=6; $z=$x+$y; Echo $z;  // Output Variable ?>

PHP Variable rules:

• The variable starts with the $ sign, followed by the name of the variable
• Variable names must begin with a letter or underscore
• Variable names cannot start with a number
• Variable names can contain only alphanumeric characters and underscores (A-Z, 0-9, and _)
• Variable names are case sensitive ($y and $Y are two different variables)

Note: The PHP variable name is case-sensitive!

<?PHP$x= 5;//Global ScopefunctionmyTest () {$y= 10;//Local Scope  Echo"Variable:</p> inside the <p> test function"; EchoThe variable x is:$x"; Echo"<br>"; EchoThe variable y is:$y";} MyTest ();Echo"Variable:</p> outside of the <p> test function";EchoThe variable x is:$x";Echo"<br>";EchoThe variable y is:$y";?>

PHP Variable Scope

In PHP, variables can be declared anywhere in the script.

The scope of a variable refers to the part of the script that a variable can be referenced/used.

PHP has three different scope of variables:

• Local (partial)
• Global (globally)
• Static (statically)

PHP Basic Learning process