PHP快速入门（1）

时间：2010-10-19 来源：Aixe

注释 <?php
 // 介是单行注释
 /* 介是多行注释... */
 echo "This is something about php ";
?>

连接字符串 <?php
 $str1 = "You will see: ";
 $str2 = "How to concat strings.";
 echo "".$str1.$str2."";
?>

条件判断 <?php
 $flag = true;
 if($flag)
 {
 echo "Under the condition...";
 }
 else
 {
 echo "Under other conditions...";
 }

 $val = 100;
 if($val == 0)
 {
 echo "It is zero.";
 }
 elseif($val < 0)
 {
 echo "It is a negative.";
 }
 else
 {
 echo "It is a positive.";
 }
?>

分支结构 <?php
 $case = 10;
 $result = "";
 switch($case)
 {
 case 1:
 $result = "In case one.";
 break;
 case 2:
 $result = "In case two.";
 break;
 case 3:
 $result = "In case three.";
 break;
 default:
 $result = "In other case.";
 break;
 }
 echo "".$result."";
?>

三元运算 <?php
 $val = 1;
 $exp = ($val == 0) ? "The value is zero" : "The value is not zero";
 echo $exp;
?>

数组array <?php
 echo "<ul>";
 $arr1 = array("John", "Jane", "Julie");
 echo "<li>People in array #1: $arr1[0], $arr1[1], $arr1[2]</li>";

 $arr2 = array(0 => "Jodan", 1 => "Jack", 2 => "James");
 echo "<li>People in array #2: $arr2[0], $arr2[1], $arr2[2]</li>";

 $arr3 = array(1 => "Tom", "Sam", "Kim");
 echo "<li>People in array #3: $arr3[1], $arr3[2], $arr3[3]</li>";

 $arr4[3] = "Avril";
 $arr4[2] = "Taylor";
 $arr4[1] = "Miley";
 echo "<li>People in array #4: $arr4[1], $arr4[2], $arr4[3]</li>";
 echo "</ul>";
?>

for循环和foreach <?php
 $fib[0] = 1;
 $fib[1] = 1;
 for($i = 2; $i < 10; $i++)
 {
 $fib[$i] = $fib[$i-1] + $fib[$i-2];
 }

 echo "The Fibonacci: ";
 foreach($fib as $index => $value)
 {
 echo (string)$value." ";
 }
 echo "";
?>

while循环 <?php
 $n = 6;
 $c = 1;
 $r = 1;
 while($c <= $n)
 {
 $r *= $c;
 $c += 1;
 }
 echo "$n != $r ";
?>

函数和递归 <?php
 function factorial($val)
 {
 if($val == 0) return 1;
 return $val * factorial($val - 1);
 }
 $n = 7;
 echo "$n! = ".(string)factorial($n)."";
?>

简单的面向对象 <?php
 class User
 {
 // fields
 private $name;
 private $email;
 private $status;

 // constructor
 function User($name, $email)
 {
 $this->name = $name;
 $this->email = $email;
 $this->status = "";
 }

 // getters
 function getName() { return $this->name; }
 function getEmail() { return $this->email; }
 function getStatus() { return $this->status; }

 // setters
 function setStatus($value) { $this->status = $value; }

 // methods
 function SignOut()
 {
 echo "User $this->name signed out.";
 }
 }

 $u = new User("John", "[email protected]");
 $u->setStatus("online");
 echo "";
 echo "Name: ".$u->getName()." ";
 echo "Email: ".$u->getEmail()." ";
 echo "Status: ".$u->getStatus()." ";
 echo "";
 echo "".$u->SignOut()."";
?>

更简单的Getter和Setter <?php
 class Rectangle
 {
 // fields
 private $offsetX;
 private $offsetY;
 private $width;
 private $height;

 // constructor & destructor
 function __construct($x, $y)
 {
 $this->offsetX = $x;
 $this->offsetY = $y;
 }

 function __destruct()
 {
 unset($this->offsetX);
 unset($this->offsetY);
 unset($this->width);
 unset($this->height);
 }

 // getters
 function __get($property)
 {
 if(isset($this->$property)) { return($this->$property); }
 else return(NULL);
 }

 // setters
 function __set($property, $value) { $this->$property = $value; }


 // methods
 function GetArea()
 {
 return $this->width * $this->height;
 }
 }

 $rect = new Rectangle(10, 20);
 $rect->width = 48;
 $rect->height = 72;
 echo "";
 echo "Offset X: ".$rect->offsetX." ";
 echo "Offset Y: ".$rect->offsetY." ";
 echo "Width: ".$rect->width." ";
 echo "Height: ".$rect->height." ";
 echo "Area: ".$rect->GetArea();
 echo "";
?>