Php beginners and beginners

Php beginners and beginners
Start and end tags

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

Php Data Types (9 types)

1. Four scalar types

• Boolean
• Integer
• Float
• String

2. Three composite types

• Array
• Object
• Callable)

3. Two special types

• Resource)
• NULL (no type)

4. Pseudo type

• Mixed (mixed type)
• Number)
• Callback (callback type, also called callable)
• Array | object
• Void

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

Super global variable

• $ GLOBALS
• $ _ SERVER: stores information about the header, path, and script location.
• $ _ REQUEST: Collect html form submitted data
• $ _ POST
• $ _ GET
• $ _ FILES
• $ _ ENV
• $ _ COOKIE
• $ _ SESSION

Access global variables in the 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: the constant name is case sensitive. The default value is false. true is not sensitive.

Create an array

• array()
• Get array Lengthcount($arr)
• Array sorting: ascendingsort(), Descending orderrsort()
• Sort array keys in ascending orderksort(), Descending orderkrsort()
• Sort array values in ascending orderasort(), Descending orderarsort()

Foreach loop (used only for arrays)

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

Magic variable

• __LINE__: Current row number
• __FILE__: Complete file path and file name
• __DIR__: Directory of the file
• __FUNCTION__: Function name
• __METHOD__: Class Method Name
• __NAMESPACE__: Name of the current namespace

Object-oriented

• Class Name is added after the class keyword is used
• Variables and methods can be defined in a pair of braces ({}) after the class name
• Class variables are declared using var, and variables can also be initialized.
• Function definitions are similar to php functions, but can only be accessed through the class and its instantiated objects.