PHP Quick Learn

Basic code

<? PHP Echo "Hello World";
?>

Variable definition

<? PHP $a=true; $bool _value=true; $integer _value=9; $float _value=3.1415926; $string _value= "pi_is_{{$float _value}}." ; Echo $string _value; // pi_is_{3.1415926}.? >

Output

<?PHP$str= "String_";$return _value=Print($str);//Success:return 1, Faile:return 0Echo $return _value;//no return value$return _value=printf("Value:%f", 3.1415926);$str=sprintf("Value:%f", 3.1415926);//Print to Variable strEcho $str;?>

Data Structures-arrays

 <? php   $season  [0]= ' Spring '   $season  [1]= ' Summer '   $season  [2]= ' Autumn '   $season  [3]= ' Winter '   $map  [' Key1 ']= ' value1 '   $map  [' Key2 ']= ' value2 '  // season & Map is all array  echo   $season   echo   $map  ; ? 

Data Structures-Objects

<?PHPclasspoint{Private $id=0;  Public $x,$y; function__construct ($x,$y)    {        $this->x=$x; $this->y=$y; }    functionPrint_info () {Echo $this->id, "<br>"; Echo $this->x, "<br>"; Echo $this->y, "<br>"; }}$p=NewPoint (1,3);$p-print_info ();?>

Data Structures-Resource data types

Similar to the concept of a handle, it needs to be destroyed when it is finished.

Data structure-NULL type

<? PHP $uninitialized ; $null _var1=null; $var= "123"; unset ($var); // This three variable is null?>

Type conversions

<?PHP//int or integer, float or double or real, string, array, object, bool or boolean//if a string starts with number, it w  Ill is truncated to a number in arithmetic//if a string starts with Non-number, it'll be is zero in Arithmetic//it's OK to Run "3.14ABC" +6, so double can be neglectableEcho(Double) "A3.1415926ABC";//intval, Doubleval, Floatval, Floatval, StrvalEcho intval(3.1415926);//var is supposed by array, Boolean, float, integer or int, null, object, Unknow, String$value= "3.1415926";$return _value=Settype($value, int);//success:1Echo $value;?>

Variable

Value pass/reference pass, mutable variable

<?PHP//by value$int 1=1;$int 2=int1;$int 2=5;Echo $int 1, "<br>",$int 2, "<br>";//1 5//by Reference$int 1=1;$int 2=&$int 1;$int 2=5;Echo $int 1, "<br>",$int 2, "<br>";//5 5//variable variables:use Variable value to define a Variable named value$sun= "Hot";$$sun= "Moon";//equal to $hot = "Moon"//${$sun} are eual to $hotEcho $sun, "<br>", ${$sun}, "<br>";//User AliasesEcho $hot, "<br>";?>

Super global variable Superglobals

• $GLOBALS
• $_SERVER
• $_GET
• $_POST
• $_FILES
• $_COOKIE
• $_SESSION
• $_REQUEST
• $_ENV

Variable destruction

Re-assign Value

Unset ()

Constant

<? PHP class test{    //The scope is thisclass    const name= "";     function classn ()    {        //user without $        Echo test::name*312;}    } // The scope is global and it can be used anywhere Define ("Site_global", "www.site.com");? >

Magic Constants

A Few "magical" PHP constants

Name	Description
__LINE__	The current line number of the file.
__FILE__	The full path and filename of the file with Symlinks resolved. If used inside an include, the name of the included file is returned.
__DIR__	The directory of the file. If used inside an include, the directory of the included file is returned. This is equivalent to dirname (__file__). This directory name does not has a trailing slash unless it is the root directory.
__FUNCTION__	The function name.
__CLASS__	The class name. The class name includes the namespace it is declared in (e.g. Foo\bar). Note that as of PHP 5.4 __class__ works also in traits. When used in a trait method, __class__ is the name of the CLASS the trait is used in.
__TRAIT__	The trait name. The trait name includes the namespace it is declared in (e.g. Foo\bar).
__METHOD__	The class method name.
__NAMESPACE__	The name of the current namespace.

Special operators

': the inverse quotation marks, equivalent to the Shell_exec () function (Safe mode can only use functions),

<? PHP echo 'dir';? >

@: Error control, placed before the expression, the resulting error is ignored. If the Track_errors property is activated, the error is stored in the $php_errormsg variable.

Foreach

<? PHP $season [0]= ' Spring '; $season [1]= ' Summer '; $season [2]= ' Autumn '; $season [3]= ' Winter '; foreach ($seasonas$s) {    echo$s, "<br>"  ;}? >

PHP Quick Learn