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PHP basic tutorial (php basic tutorial) some code_PHP tutorial

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Release： 2016-07-21 15:13:52
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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 study it yourself for details
PHP environment installation:
The usual combination of PHP is: MySql+PHP+Apche, there is also IIS+PHP+MySQL or SqlServer
Of course we can choose the combination package for installation. Newbies are advised to install AppServ or phpnow, etc.
You can use this installation and running under iis to support php. Mysql needs to be installed.
You can also install each part yourself. Then configure it yourself.
PHP download address: 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 http://www .jb51.net/article/33062.htm
Writing tools: It is recommended to use Notepad++ or dreamweaver cs4
========================== ===========================================
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 like this, 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 based on the way the variable is declared.
Declaring variables in PHP is declared using the $ keyword - 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 ;
Show results: SNOW
*/
? & GT;


Constant:
Police in PHP:
State the define function in PHP to declare the constant using the define function to use the define function declared. Directly look at the code



Copy the code

The code is as follows:


/* There are three define functions 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--can only be Boolean, integer, floating point, character String four types 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 presets in PHP Define constants--you can check the PHP manual or related information
==================================== ==================================
Array: --PHP’s array is 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. --Look directly at the code


Copy the code

The code is as follows:

/*==================================== ================================*/
//Numerical array
$nums = array(1 ,2,3);
                                                                                           echo $nums[2]."
";
/*Output: 4*/
/*=================== ================================================*/
//Associative array --The "=>" is the association symbol in PHP, which specifies key-value pairs.
         $ns = array("name"=>"Zhang San","age"=>22,"sex"=>"man");                                                             ns["name"] = "Zhang San";
        $ns["age"] = 22;
        $ns["sex"] = "man";
                                                                                                                                     ns["name"]                                       ns["name"]."
Age:".$ns["age"]."
Sex:".$ns["sex"]."
";
                                                          ==== ================================================== =======*/
//Multi-dimensional array--arrays can also be stored in the array
,"age"=>"23","gender"=>"male"),"小红"=>array("hobby"=>"eating","gender"=>"female" ));
                                                     $bs =         "Hobby" =>"Computer",
"Age"=>"23",
"Gender"=>"Male"
" ),
"Xiaohong"=>array
                                                                                                                                                                                                                                                                    //Or equivalent to
$bs[ "Xiaohong"]["Gender"] = 2; $bs["Xiaohong"]["Hobby"] = 2; //....
                                                                                                             "] = array("Hobby"=>"Computer","Age"=>"23","Gender"=>"Male"); $bs["小红"] = array("Hobby" = & gt; "Eat", "Gender" = & GT; "Female");
Echo $ bs ["Little Red"] [Gender "]." Output: Female*/
/*========================================== ===========================*/
?>


=====================================================================
 PHP运算符: --摘录w3school的教程
　　
本部分列出了在 PHP 中使用的各种运算符：
算数运算符
运算符 说明 例子 结果
+ 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
赋值运算符
运算符 说明 例子
= 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

比较运算符

运算符 说明 例子
== 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<8 returns true
>= is greater than or equal to 5>=8 returns false
<= is less than or equal to 5<=8 returns true

逻辑运算符

运算符 说明 例子
&& and x=6
y=3

(x < 10 && y > 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:

& lt;? PHP
$ name = "Zhang San"; // State the variable
/*If..lse that only one of the statements will be executed, one condition is established. Even if the later ones are established, it will be ignored*/
// determine whether the name is Zhang San
if ($ name == "Zhang San")
{
echo "Zhang San";
} else if ($ name == "Li Si") // Then judge
{
echo "Li Si"; 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)
{
case 1:
echo "一";
break;
case 2:
echo "二";
break;
default: //Default branch. Executed when none of the conditions are true.
                      echo "other";                                                                                                                                                                                                                                   🎜>

PHP Loop:

Same as other strongly typed programming languages. PHP also has while, do while, for, and foreach -- just look at the code




Copy code

The code is as follows:
& lt;? PHP
$ Index = 1;
While ($ Index & LT; = 10)
{
Echo ".
";
                                                                                                                                                                                                                                                                                        ; 🎜>         $index = 1; }
while($index <=1);

/*The above results are output once*/
echo '
';
for($index = 1; $index <=3;$index++)
                                                                                                                                                                                                                                 The above result is output 3 times */
                                                                                                                                                                                                                                            have been have been been been been been —              been been been been been been. Temp) // Traversing the array
{
echo ":". $ Temp. "& LT; br /& gt;"
}
/*results output 3 times* /
?>


PHP function:

The declaration of a php function is very simple. Just add the keyword function in front and followed by the function name. --Please see the code directly for the specific format



Copy the code

The code is as follows:


/*PHP function / Parameter function - the passed-in parameter can also be a class object
function MyEcho2($str)
{
echo $str;
}

MyEcho(); //output ：No parameter function

MyEcho2("Heheheha!"); //Output: Hehehaha!
?>

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, please study it yourself

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
                                             $test = "Test static method"; //Define public variables
                                                                                                                                                                                                   " symbol means class call
                                                                                                                                                       = $Num1;
                                                                                                                                                                                                                                    🎜>           {
                                                                                  "
".MyClass::$test."
";                                                         = new MyClass;
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:



"xx"]."
"; //Read the post value
                  echo $_REQUEST["xx"]; Try it yourself
?>

< input type="submit" value="Submit" />
 

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

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Before this tutorial, I will not talk about the commonly used PHP in a long way. Regarding what is a variable, what is a judgment statement, etc., please check the relevant information by yourself. This tutorial is aimed at those who have...




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