PHP_ Basics, PHP Basics _php Tutorials

PHP_ Basics, PHP basics

Directory

• Array

• Function

• Classes and objects

• String manipulation

• Session control

• Time and date

• Exception handling

One, array

　　1. Indexed array

Header("content-type:text/html; Charset=utf-8 ");//create an empty array$str=Array();//indexed array: The key of an array is an array of integers, and the integer order of the keys starts at 0, and so on. $fruit=Array("Apple", "banana", "pineapple");//Indexed array Assignment://1. Assign a value with the name of the array variable followed by a bracket$arr[0]= ' Apple ';//Use the-= symbol to separate keys and values, the left for the key, and the right for the value. Array(' 0 ' = ' apple ');//count ($arr) returns the array length//for iterating through the values in the indexed array for($i= 0;$i<Count($fruit);$i++){    Echo"$fruit[$i]
";}//foreach iterates through the values in an indexed arrayforeach($fruit  as $k=$v){    Echo $k." ...".$v."
";}

2. Associative arrays

Header ("content-type:text/html; Charset=utf-8 "); // associative array: The key of an exponential group is an array of strings $fruit Array (' apple ' = ' apple ', ' banana ' and ' banana ', ' pineapple ' and ' pineapple '); // Associative array assignment//1. Assign a value with the name of the array variable followed by a bracket $arr [' Apple ']= ' Apple '; // 2. Use the-= symbol to separate the keys and values, the left for the key, and the right to indicate the value Array (' apple ' = ' apple '); // The Foreach loop accesses the values in the associative array foreach ($fruitas$k=$v) {    echo '
The English key name of the fruit: '. $k. ', the corresponding value is: '. $v ;}

Second, function

1. Variable functions

// A variable function that invokes a function by its value function name () {    echo ' Jobs ';} $func = ' name '; // calling a mutable function $func

2. Determine if a function exists

function func () {} if (function_exists(' func ')) {    echo ' exists ';}

III. Classes and objects　

//define a classclassCar {//Defining Properties     Public $name= ' car '; //Defining Methods     Public functionGetName () {//You can use the $this pseudo-variable to invoke an object's properties or methods inside a method        return $this-name; }}//instantiate an object$car=NewCar ();//methods for calling objectsEcho $car-getName ();//class//public: Exposed//protected: Protected, protected property does not allow external calls to//private: private, private property does not allow external calls//static methods: Use keyword static modifiers//static methods do not need to instantiate objects , which can be called directly from the class name, and the operator is double-colon:classCar { Public Static functionGetName () {returnCar; }}EchoCar::getname ();//The result is "car"//constructor __construct (): Call this function every time the object is created//destructor __destruct (): Call this function every time the object is destroyedclassCar {//add constructors and destructors    function__construct () {Print"constructor is called \ n"; }    function__destruct () {Print"destructor is called \ n"; }}$car=NewCar ();

Four, string manipulation

　　1. The difference between single and double quotes

// String variables directly contained in double quotation marks//the contents of a single quote string are always considered ordinary characters $str= ' Hello '; Echo $str // Run Result: STR is Hello Echo // operation Result: STR is $STR

2. Remove whitespace from the string

// trim removes spaces at both ends of a string. RTrim is to remove a string to the right of the space//ltrim is to remove the left space of a string trim("space");

3. Get the length of a string

// English character length strlen ($str); // Chinese character length mb_strlen ($str, "UTF8");

4. Interception of strings

// The Intercept function of the English string substr ()//substr (string variable, start intercept position, intercept number)$str= ' I love you '; Echo substr ($str, 2, 4); // Chinese string intercept function Mb_substr ()//mb_substr (string variable, start intercept position, intercept number, page encoding)$str= ' I love you, China '; echo mb_substr ($str, 4, 2, ' UTF8 ');

5. String Lookup

// Strpos (string to be processed, string to position, starting position of position [optional]) $str = ' I want to study at IMOOC '; $pos Strpos ($str, ' Imooc ');

6. String substitution

// Str_replace (The string to find, the string to replace, the string to be searched, and the replacement to count [optional]) $str = ' I want to learn JS '; $replace Str_replace $str);

7. Merging and splitting of strings

// string merge function implode (): combines array elements into a single string//implode (delimiter [optional], array) $arr Array (' Hello ', ' world! ' ); $result implode $arr ); Print_r ($result); // The result shows the Hello world!//string-delimited function explode (): The function returns an array of strings consisting of//explode (delimiter [optional], string) $str = ' Apple,banana '; $result Explode $str ); Print_r ($result); // results show Array (' Apple ', ' banana ')

V. Session CONTROL

1.cookie

// setting Cookie//name (cookie name) can be accessed via $_cookie[' name ']//value (the value of the cookie)//expire (Expiration Time) UNIX timestamp format, default is 0, indicating that the browser is off as expired// Path (valid path) if the path is set to '/', the entire site is valid//domain (valid domain) by default the entire domain name is valid, if ' www.imooc.com ' is set, then only valid in www subdomain $value = ' Test '; Setcookie $value ); // valid for one hour Setcookie $value  Time () +3600); // deletion and expiry time of cookies Setcookie  Time ()-1);

2.session

// First Execute Session_Start method to open session Session_Start (); // the session reads and writes through the global variable $_session.  $_session[' name '] = ' jobs '; Echo $_session [' name ']; // Delete a session unset ($_session[' name ']); // Delete all session Session_destroy ();

Vi. Time and date

// UNIX timestamp: Represents the sum of the number of seconds from January 1, 1970 00:00:00 to the current time. The function time () to get the timestamp of the current time of the server $time= times(); Echo $time ; // The date () function, to get the current date//date (timestamp format, specify the timestamp "default is the current date and time, optional")//Set the default time zone date_default_timezone_set (' asia/ Shanghai '); // date of output 1396193923 Echo Date ("y-m-d"); // function Strtotime: Gets the timestamp of a date, or gets the timestamp of a time//strtotime (the time string to parse, the timestamp of the computed return value "default is the current time, optional")// 1398700800, this number represents a 1,398,700,800-second echostrtotimefrom January 1, 1970 00:00:00 through April 29, 2014 (' 2014-04-29 '); // 1398700801, this number represents 1,398,700,801 seconds from January 1, 1970 00:00:00 to 2014-04-29 00:00:01 Echo Strtotime (' 2014-04-29 00:00:01 ');

Vii. Exception Handling

//to create a function that throws an exceptionfunctionChecknum ($number){    if($number>1){        Throw New Exception("Exception hint-number must be less than or equal to 1"); }    return true;}//to trigger an exception in a "Try" code blockTry{checknum (2); //If the exception is thrown, then the following line of code will not be output    Echo' If you can see this hint, your number is less than or equal to 1 ';}Catch(Exception $e){    //Catching exceptions    Echo' Catch exception: '.$e-getMessage ();}//exception has several basic properties and methods, including the following://message exception message content//code exception code//file throws exception file name//line throws exception in the number of rows in the file//the methods commonly used are://gettrace Get exception tracking Information//gettraceasstring get exception tracking information string//getmessage get error messageclassMyExceptionextends Exception {    functionGetInfo () {return' Custom error message '; }}Try {    Throw NewMyException (' ERROR ');} Catch(Exception $e) {    Echo $e-getInfo ();}

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