PHP basic tutorial (php basic tutorial) some code code_php basics

Before this tutorial, I will not talk about the common uses of PHP in a long and uniform way. Regarding what is a variable, what is a judgment statement, etc., please check the relevant information by yourself. This tutorial is intended for people who have a programming foundation and are new to PHP. The article is relatively simple. Mainly depends on the structure. Please do more research on your own for details
PHP environment installation:
The usual combination of PHP is: MySql PHP Apche also has IIS PHP MySQL or SqlServer
Of course we can choose the combination package for installation. Newbies are advised to install AppServ or phpnow, etc.
Under iis, you can use this to install and run it to support php. Mysql needs to be installed.
You can also install each part yourself. Then configure it yourself.
Download addresses of various versions of PHP: http://museum.php.net/php5/
Apche download address:http://prdownloads.sourceforge.net/appserv/ appserv-win32-2.5.10.exe?download
MySQL download address: http://www.mysql. cn/
Configuration and installation tutorial: http://wenku.baidu.com/view/ c6118b1810a6f524ccbf85f9.html
Or /article/33062.htm
Writing tools: Notepad or dreamweaver cs4 is recommended ================================================ ====================
Syntax:
The syntax of PHP is very simple - just look at the code: This is how PHP code is declared. Note: ?> can also be written, but it is not recommended.
Mark the end of a statement: The semicolon marks the end of a statement ";" -- a ";" semicolon should be used after each statement to indicate the end.
============ ================================================== ========
Comments in PHP: --See the code in the tutorial
for details. Comments in PHP have single-line comments: //This is the comment
and the large module comment: /* This is a comment*/
============================================ ===========================
Variables:
PHP variables are loose. But it is also case-sensitive, so everyone should pay attention to this. There is no need to declare it before using it - PHP will automatically convert the variable into the correct data type according to the way the variable is declared.
Declaring variables in PHP uses the $ keyword to declare - all variables are identified by $
Variable naming rules:
Variable names must start with a letter or underscore "_".
Variable names can only contain alphanumeric characters and underscores.
Variable names cannot contain spaces. If the variable name consists of multiple words, they should be separated by underscores (such as $my_string) or start with a capital letter (such as $myString).
Note: (Basically all programming languages ​​have similar variable naming rules!)

Example:

Copy code The code is as follows:

//Declare variables
/ Declare constants using the define function. Look directly at code

Copy code The code is as follows:

/*
The define function has three parameters
The first parameter: Specify the constant name--keywords are not allowed, and the constant cannot have the $ symbol
The second parameter: Specify the value of the constant--it can only be Boolean, Four types: integer, floating point, and string
The third parameter: Specify whether this constant is case-sensitive--true ignores case, false case-sensitive
*/
define("Name" ,"Zhang San",true);
echo name;
/*Display result: Zhang San--because it is true, it is not case sensitive*/
?>

There are also predefined constants in PHP - you can check the PHP manual or related information
============================== ========================================
Array: --PHP array Still relatively simple and easy to use.
PHP arrays can be used as collections in other languages
PHP arrays can store any type supported by PHP. Of course, you can also store class objects, etc. - just look at code

Copy code The code is as follows:

/*========================== =========================================*/
//Numeric array
          $nums = array(1,2,3);
                 // Or equivalent to  
           $nums[0] = 1; [2] = 4;
echo $nums[2]."
";
/*Output: 4*/
/*============== ================================================== ====*/
//Associative array --The "=>" is the association symbol in PHP, which specifies key-value pairs.
           $ns = array("name"=>"张三","age"=>22,"sex"=>"man");                                                           "] = "Zhang San";
                           $ns["age"]                                                                                                                                                                                                              ​"]."
Age:".$ns["age"]."
Sex:".$ns["sex"]."
";
/*Output:
Name: Zhang San
Age: 22
Gender: man
*/
/*======================== ============================================*/
/ /Multidimensional array--Arrays can also be stored in the array
$bs = array("张三"=>array("Hobby"=>"Computer","Age"=>"23","Gender"=>" Male"),"Xiaohong"=>array("Hobby"=>"Eating","Gender"=>"Female"));
//Adjust the format so that everyone can see it more clearly
bs = array
        (
                                                                                                                                                                                                                                                                                        
"Gender" =>"male"
 " >"女"
)
       );
          // Or equivalent to ....
                                                                                                                                                                                                                                                $bs ["小红"] = array("Hobby"=>"Eating","Gender"=>"Female");
        echo $bs["小红"]["Gender"]."
";
          /*Output: Female*/
                                                                                                   ==================================*/
?>

================================================ ======================
PHP operators: --Excerpt from w3school's tutorial

This section lists the operators used in PHP Various operators:
Arithmetic operators

Operator	Description	Example	Results
	Addition	x=2 x 2	4
-	Subtraction	x=2 5-x	3
*	Multiplication	x=4 x*5	20
/	Division	15/5 5/2	3 2.5
%	Modulus (division remainder)	5%2 10%8 10%2	1 2 0
	Increment	x=5 x	x=6
--	Decrement	x=5 x--	x=4

Assignment operator

Operator	Description	Example
=	x=y	x=y
=	x =y	x=x y
-=	x-=y	x=x-y
*=	x*=y	x=x*y
/=	x/=y	x=x/y
.=	x.=y	x=x.y
%=	x%=y	x=x%y

Comparison operators

Operator	Description	Example
==	is equal to	5==8 returns false
!=	is not equal	5!=8 returns true
>	is greater than	5>8 returns false
	is less than	5
>=	is greater than or equal to	5>=8 returns false
	is less than or equal to	5

Logical operators

Operator	Description	Example
&&	and	x=6 y=3 (x 1) returns true
||	or	x=6 y=3 (x==5 || y==5) returns false
!	not	x=6 y=3 !(x==y) returns true

Program judgment statement:

It is the same as C#, java, C and other judgment statements.There are if..else/else..if and switch statements - look directly at Code

Copy code The code is as follows:

$name = "Zhang San"; //Declare variables
/*if..else will only execute statements One, one condition is established. Even if the following is true, it will be ignored*/
                                                                                                                                                                                                        Determine whether the name is Zhang San.
}
Else if ($ name == "Li Si") // Then judge
{
echo "Li Si";
}
else // or above is not just Go into else
                                                                                                                                                                                                        ; > The principle of switch selection structure and if is similar. Just add break in the case -- of course you don't have to add it.
In this case, after executing case 1, it will not jump out, but continue to execute the next case branch. Don't jump out until you encounter a break. You can try it yourself
          */
        switch($num)   
                                                                                                                                                  2:
echo "二";
              break; Executed when none of the conditions are true.
             echo "other";一
                                                                               >

PHP loop:

It is the same as other strongly typed programming languages. PHP also has while, do while, for, and foreach -- look at the code directly

Copy code The code is as follows:

$index = 1;
while($index {
echo "th". $index."times"."
";
                                                                                                $index. ;
         $index = 1; > while($index
/*The above results are output once*/
echo '
';
for($index = 1;$index echo '
';
$index = array("1","2","3");
foreach($index as $temp) //Traverse the array
{
echo "Value:".$temp."
";
}
/*The above results are output 3 times*/
?>

PHP function:

The declaration of a PHP function is very simple. Just add the keyword function followed by the function name. --Please see code

Copy code The code is as follows:

/*PHP function*/
Echo "Portomless function
}
// There are participation functions-the passing parameters can also be class objects. BR>            echo $str;
                                                                                                                                                                                                                                                                                    ;
?>

PHP class:

PHP, like other high-level languages, supports object-oriented programming. Here I talk about the declaration of the basic part of the php class. Regarding object-oriented programming, you can do your own research

When declaring a class in PHP, you also need to add the keyword class - see code for details - (including static functions, function calls, etc.)

Copy code The code is as follows:

class MyClass //Class declaration
jum2;
          static public $test = "Test static method"; //Define public variables
           function Calc() //                                                                                                                                                                            . / "->" symbol means class call
                                                                                                                                                          um1 ;
$ this->JUM2 = $ num2;
Return $ this; // Here the class object itself
}

Static function tt ()
{
echo echo "
".MyClass::$test."
";                   > echo $temp->SetNum(2,8)->Calc(); //Output:10
MyClass::Tt(); //"::"Static call //Output: test static method
? >

PHP form processing:

When the page user submits the value, use $_GET and $_POST or $_REQUEST (which includes $_GET, $_POST and $_COOKIE) system-defined variables to read the submitted value - see code

Copy code The code is as follows:

echo $_POST["xx"]."
"; //Read post value
echo $_REQUEST["xx"];
//Use get to read the value. Try it yourself
?>

That's all for now... If I have time, I will write down the commonly used applications of PHP. Advanced section. (Including sessions, cookies, object-oriented, common functions, etc.)