1. php tags
<?php
echo 'Hello';
?>
2. Constant constTHE_VALUE = 100;
define('THE_VALUE',100);
variable $a=10;
3. Function
functiontraceHello($name){
echo 'hello '.$name.'<br>';//String connection
//echo "hello $name <br>";
return 1;//return value
}
transfer:
1. traceHello('zhangsan');
2. $ func = 'traceHello'
$func('zhangsan');
4. Process Control
1.if else
function getLevel($score){
if($score>=90){
return 'excellent';
}elseif($score>=80){
return 'good';
}else{
return 'not good';
}
}
2.switch
function getLevel($score){
$result = 'bad';
switch(intval($score/10)){//intval() round up or take out the integer
case 10:
case 9:
$result = 'Excellent';
break;
case 8:
$result = 'good';
break;
default:
$result = 'bad';
//break;
}
return $result;
}
3.for loop
for($i=0;$i<100;$i++){
if($i==20){ break; }
if($i==40){ continue; }
}
4.while loop
$i=0;
while(%<10)
...
$i++;
}
5. do while loop
$i=0;
do{
...
$i++;
}while($i<100);
5. Logical Operators
|| && ！
6. Common methods of strings
strpos($str,'o');
substr($str,2);
str_split ();
explode(' ',$str);
7. Arrays
$arr=array();
$arr[0]='Hello';
print_r($arr);
$arr['h']='hello';
$arr['w']='world';
$arr =array('h'=>'hello','w'=>'world')
8.require 'lib.php';//Dependency, there is no error in the file
require_once 'lib.php';//Only referenced once
include 'lib.php';//Include, the file does not exist and give a warning
9. Declare the class
namespace jk;//namespace
class Man{
private $_age,$_name;
private static $NUM = 0;//Static variable
/**
* @param int $age age
* @param string $name name
public funcation _construct($age,$name){
$this-> _age = $age;//this current object pointer, self current class pointer, parent parent class pointer
$this-> _name = $name;
}//Construction method
public funcation sayHello(){}//Member method
public static funcation say(){}//Class method
}
Create instance
$a=new Man();
$a->sayHello();//Call the method
Man::say();
$h = new\jk\Hello();//There is a namespace
10. Class inheritance, overriding methods
class Child extends Man{
publicfunction _construct($age,$name){
parent::_contruct($age,$name);
}
publicfunciton say(){//Override method
//parent::say(); //retain the parent class method
echo 'child';
}
}
11. Common library functions
time();//timestamp
date_default_timezone_set('Asia/Shanghai');//Time zone setting
date('Ymd H:i:s');//time
date('Ymd H:i:s', time());//Timestamp converted to time
$obj =array('h'=>'Hello','w'=>'World');
echo json_encode($obj);//Convert to json format
$jsonStr ='{"h":"Hello","w":"World"}';
$obj =json_decode($jsonStr);//json string is converted to php object
$f = @fopen('data','w');//Open the file, @ does not output a warning
fwrite($f,'hello');//Write the file
fclose($f);
$f = @fopen('data','r');
while(!feof($)){//Determine whether the end of the file is reached
$content =fgets($f);//Only one line can be read
echo$content;
}
echofile_get_contents('data');//Get the file directly
die('end page');
12. Get get parameters and post parameters
if(isset($_GET['name'])&& $_GET['name']){}//isset() to determine whether the variable is set empty($name) to determine whether the variable is assigned a value
13. Get files
$file = $_FILES['file'];
$fileName = $file['name'];
move_uploaded_file($file['tmp_name'],$fileName);
14.cookie和session
setcookie('name','cheng');
header('Location:a.php');//Jump
//a.php
echo $_COOKIE['name'];//Get cookies
session_start();//Enable session
$_SESSION['name'] ='cheng';
echo session_id();//Get sessionid
echo$_SESSION['name'];//
session_destroy();//销毁session
15. mysql database
$conn =mysql_connect('localhost','root','password');
mysql_select_db('mydb',$conn);
$result =mysql_query("SELECT * FROM users");//Query, or update, or delete
$result_arr =mysql_fetch_array($result);//Fetch one item at a time, in the form of an array, with an index
$result_arr =mysql_fetch_assoc($result);//No index
$data_count =mysql_num_rows($result);//Get the number of data rows
if(mysql_errno()){
echomysql_error();//Get the error
}
16.PDO
PHP data objects, which provide an abstraction layer for database access, use the same methods no matter which database is used.