PHP Beginner's mind

Start and end tags

1. There are two common types: <?php ?><script language="php"></script>
2. Short mark: <? ?> , need to open the short_open_tag instruction of php.ini file
3. ASP style tag: <% %> , need to open the asp_tags instruction of php.ini file

PHP Data type (9 types)

1. Four types of scalar

• Boolean
• Integer
• Float
• String

2. Three types of composite

• Array
• Object
• Callable (callable)

3. Two special types of

• Resource (resources)
• NULL (no type)

4. Pseudo type

• Mixed (mixed type)
• Number (numeric type)
• Callback (callback type, also known as callable)
• Array|object
• void

5. Pseudo-Variable $ ...
6. Type detection function (is_type), eg:is_string($str)

Super Global variables

• $GLOBALS
• $_server: Saving information about headers, paths, script locations, and more
• $_request: Collecting data submitted by HTML forms
• $_post
• $_get
• $_files
• $_env
• $_cookie
• $_session

Accessing global variables in a function body

• Global $variable _name
• $GLOBALS [Variable_name]

Set constants

define(const_name, const_value, boolean)

• Const_name: Constant Name
• Const_value: Constant Value
• Boolean: Constant name case sensitive, default false sensitive, true insensitive

Create an array

• array()
• Get array lengthcount($arr)
• Array sort: Ascending sort() , descendingrsort()
• Array key sort: ascending ksort() , descendingkrsort()
• Array value sort: ascending asort() , descendingarsort()

foreach Loop (for arrays only)

• foreach($array as $value) {}
• foreach($array as $key => $value) {}

Magic variable

• __LINE__: Current line number
• __FILE__: File full path and filename
• __DIR__: The directory where the files are located
• __FUNCTION__: function name
• __METHOD__: The method name of the class
• __NAMESPACE__: The name of the current namespace

Object oriented

• class uses the class keyword followed by the name definition
• Variables and methods can be defined within a pair of curly braces ({}) after the class name
• A variable of a class is declared with Var, and a variable can initialize a value
• A function defines the definition of a PHP function, but is accessible only through the class and its instantiated objects

PHP Beginner's mind