


PHP array definition and traversal, PHP array functions and multi-dimensional arrays
The definition of PHP array and array traversal, the usage and examples of PHP array functions, PHP array value assignment, the loop output of PHP multi-dimensional array, etc. are provided for your study and reference.
1. PHP array definition and traversal 2. php array function 1. Array definition: $arr=array(1,2,3);//Index array, all subscripts are numbers $arr=array("name"=>"user1","age"=>"30");//Associative array, the subscript contains letters //There are only two kinds of subscripts, either letters or numbers without double quotes 1,3,"age"=>4,5,100=>6,7,400=>8,9); echo ""; print_r ($arr); echo ""; ?> 2. Array subscript: if it is a letter $arr=array("name"=>1,3,"age"=>4,5,100=>6,7,400=>8,9); //Subscript printing: "name" 0 [name] => 1 [0] => 3 [age] => 4 [1] => 5 [100] => 6 [101] => 7 [400] => 8 [401] => 93. Array value: 1. Output the entire array print_r($arr) 2. Output a value in the array $arr=array("name"=>1,3,"age"=>4,5,"100"=>6,7,"400"=>8,9); echo $arr['age']; echo ""; echo $arr[100]; 3.Array assignment: 1.$arr['age']=30; Array assignment can also define arrays: $arr[]=1; $arr[]=2; 4.Array traversal: 1.for loop The first ".($i+1)."The individual's name is {$arr[$i]}"; } ?>Loop plus judgment: The first ".($i+1)."The individual's name is {$arr[$i]}"; }else{ echo "th".($i+1)."The individual's name is {$arr[$i]}"; } } ?>2.foreach loop foreach performs array traversal: "; print_r ($arr); echo ""; foreach($arr as $key=>$val){ $num++; if($num%2==1){ echo "{$key}:{$val}"; }else{ echo "{$key}:{$val}"; } } ?>3.while....list ..each loop traversal while(list($key,$val)=each($arr)){ echo $key.$val; } //It is recommended to use foreach to traverse the arrayMultidimensional Arrays: 1. One-dimensional array $arr=array(1,2,3); $arr[0]; 2. Two-dimensional array $arr=array(1,2,array(4,5)); $arr[2][0]; 2. Two-dimensional array $arr=array(1,2,array(3,array(4,5))); $arr[2][1][0]; Two-dimensional array traversal: "; print_r($arr); echo ""; echo ""; foreach($arr as $val){ if(is_array($val)){ foreach($val as $val2){ echo $val2." "; } } else{ echo $val." "; } } ?> Three-dimensional array value: "; print_r($arr); echo ""; echo ""; foreach($arr as $val){ if(is_array($val)){ foreach($val as $val2){ if(is_array($val2)){ foreach($val2 as $val3){ echo $val3." "; } }else { echo $val2." "; } } } else{ echo $val." "; } } ?> //It is recommended to use one-dimensional array and two-dimensional array A data table is actually a two-dimensional array, and each row of records in it is a one-dimensional array. Query database: "; print_r($row1); echo ""; ?>Super global array: superglobal array $_SERVER $_GET $_POST $_REQUEST $_FILES $_COOKIES $_SESSION $GLOBALS $_SERVER View server information "; print_r($_SERVER); echo ""; ?>Apache/2.2.8 (Win32) PHP/5.2.6 Server at localhost Port 80 [SERVER_SOFTWARE] => Apache/2.2.8 (Win32) PHP/5.2.6 [SERVER_NAME] => localhost//server domain name [SERVER_ADDR] => 127.0.0.1//Server ip [SERVER_PORT] => 80//Port number [REMOTE_ADDR] => 127.0.0.1 //Client access ip [DOCUMENT_ROOT] => E:/AppServ/www [SERVER_ADMIN] => goxuexi@126.com [SCRIPT_FILENAME] => E:/AppServ/www/index.php //The absolute path of the script file name [REMOTE_PORT] => 49881 [GATEWAY_INTERFACE] => CGI/1.1 [SERVER_PROTOCOL] => HTTP/1.1 [REQUEST_METHOD] => GET [QUERY_STRING] => //Request string [REQUEST_URI] => ///Request url address [SCRIPT_NAME] => /index.php//Script name (relative to website root directory) [PHP_SELF] => /index.php [REQUEST_TIME] => 1407568551//Access time [argv] => Array ( ) [argc] => 0 ) $_GET gets the data submitted using get http://localhost/index.php?id=10&name=user1 Communication between two pages: 1. Form value passing The first: get method The second way: post method 2.a tag passing value You can only use the get method The a tag recommends using the get method to submit data. It is recommended to use post method to submit data in forms. magic_quotes_gpc = on; means that when the get request is enabled, the ' in the get data will be preceded by get instance: index.php junzai3 junjun4 junjun5 rev.php 欢迎:姓名:年龄:post实例 $_POST:获取表单post过来的数据 index.php 提交用户信息rev.php 欢迎:姓名:年龄:$_REQUEST 获取a或者表单get或post过来的数据. $_COOKIES 同一个页面在多个页面获取 $_SESSION 同一个变量在多个页面获取到 $_FILES 获取表单中的文件,并生成一个数组. $GLOBALS $GLOBALS[_SERVER] $GLOBALS[_GET] $GLOBALS[_POST] $GLOBALS[_FILES] $GLOBALS[_REQUEST] $GLOBALS[_COOKIES] $GLOBALS[username]//包含页面内的全局变量,并且通过$GLOBALS[username]="user2"改变$username的值. 例子,使用$GLOBALS改变全局变量的值. "; print_r($GLOBALS); echo ""; ?> |

PHPsessionstrackuserdataacrossmultiplepagerequestsusingauniqueIDstoredinacookie.Here'showtomanagethemeffectively:1)Startasessionwithsession_start()andstoredatain$_SESSION.2)RegeneratethesessionIDafterloginwithsession_regenerate_id(true)topreventsessi

In PHP, iterating through session data can be achieved through the following steps: 1. Start the session using session_start(). 2. Iterate through foreach loop through all key-value pairs in the $_SESSION array. 3. When processing complex data structures, use is_array() or is_object() functions and use print_r() to output detailed information. 4. When optimizing traversal, paging can be used to avoid processing large amounts of data at one time. This will help you manage and use PHP session data more efficiently in your actual project.

The session realizes user authentication through the server-side state management mechanism. 1) Session creation and generation of unique IDs, 2) IDs are passed through cookies, 3) Server stores and accesses session data through IDs, 4) User authentication and status management are realized, improving application security and user experience.

Tostoreauser'snameinaPHPsession,startthesessionwithsession_start(),thenassignthenameto$_SESSION['username'].1)Usesession_start()toinitializethesession.2)Assigntheuser'snameto$_SESSION['username'].Thisallowsyoutoaccessthenameacrossmultiplepages,enhanc

Reasons for PHPSession failure include configuration errors, cookie issues, and session expiration. 1. Configuration error: Check and set the correct session.save_path. 2.Cookie problem: Make sure the cookie is set correctly. 3.Session expires: Adjust session.gc_maxlifetime value to extend session time.

Methods to debug session problems in PHP include: 1. Check whether the session is started correctly; 2. Verify the delivery of the session ID; 3. Check the storage and reading of session data; 4. Check the server configuration. By outputting session ID and data, viewing session file content, etc., you can effectively diagnose and solve session-related problems.

Multiple calls to session_start() will result in warning messages and possible data overwrites. 1) PHP will issue a warning, prompting that the session has been started. 2) It may cause unexpected overwriting of session data. 3) Use session_status() to check the session status to avoid repeated calls.

Configuring the session lifecycle in PHP can be achieved by setting session.gc_maxlifetime and session.cookie_lifetime. 1) session.gc_maxlifetime controls the survival time of server-side session data, 2) session.cookie_lifetime controls the life cycle of client cookies. When set to 0, the cookie expires when the browser is closed.


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