php数组排序之ksort-对数组的元素键名进行升序排序

<?php
$my_array = array("e" => "Dog", "b" => "Cat", "c" => "Horse");
ksort($my_array);
print_r($my_array);
?>输出：

Array(    [b] => Cat    [c] => Horse    [e] => Sog)

<?
/*
* 定义了 User接口.
* 和子类 NormalUser,VipUser,InnerUser
*/
//User接口,定义了三个抽象方法.
interface User{
 public function getName();
 public function setName($_name);
 public function getDiscount();
}
abstract class AbstractUser implements User{
 private $name = ""; //名字
 protected  $discount = 0; //折扣
 protected  $grade = "";  //级别
 
 public function __construct($_name){
  $this->setName($_name);
 }
 public function getName(){
  return $this->name;
 }
 public function setName($_name){
  $this->name = $_name;
 }
 public function getDiscount(){
  return $this->discount;
 }
 
 public function getGrade(){
  return $this->grade;
 }
}
class NormalUser extends AbstractUser  { 
 protected  $discount = 1.0;
 protected  $grade = "NormalUser";
}

class VipUser extends AbstractUser {
 protected  $discount = 0.8;
 protected  $grade = "VipUser";
}

class InnerUser extends AbstractUser {
 protected  $discount = 0.7;
 protected  $grade = "InnerUser";
}
?>

<?
include_once("./class/User.php");
include_once("./class/Product.php");
include_once("./class/ProductSettle.php");

$number = 10;
$book = new BookOnline("设计模式");

$user = new NormalUser("Tom");
$price = ProductSettle::finalPrice($user,$book,$number);
$str =  "您好，尊敬的用户 " . $user->getName() . " <br>";
$str .= "您的级别是 ". $user->getGrade() .", <br>";
$str .= "您的折扣是 " . $user->getDiscount() . "<br>";
$str .= "购买 $number 本 《 ". $book->getProductName() ;
$str .=  "》的价格是 $price <br><br>";
echo $str;

$user = new vipUser("Tom");
$price = ProductSettle::finalPrice($user,$book,$number);
$str =  "您好，尊敬的用户 " . $user->getName() . " <br>";
$str .= "您的级别是 ". $user->getGrade() .", <br>";
$str .= "您的折扣是 " . $user->getDiscount() . "<br>";
$str .= "购买 $number 本 《 ". $book->getProductName() ;
$str .=  "》的价格是 $price <br><br>";
echo $str;

$user = new InnerUser("Tom");
$price = ProductSettle::finalPrice($user,$book,$number);
$str =  "您好，尊敬的用户 " . $user->getName() . " <br>";
$str .= "您的级别是 ". $user->getGrade() .", <br>";
$str .= "您的折扣是 " . $user->getDiscount() . "<br>";
$str .= "购买 $number 本 《 ". $book->getProductName() ;
$str .=  "》的价格是 $price <br><br>";
echo $str;
?>

<?php
$my_array = array("a" => "Dog", "b" => "Cat", "c" => "Horse");
rsort($my_array);
print_r($my_array);
?>输出：

Array
(
[0] => Horse
[1] => Dog
[2] => Cat
)
Like sort(), rsort() assigns new keys for the elements in array. It will remove any existing keys you may have assigned, rather than just reordering the keys.  This means that it will destroy associative keys.

$animals = array("dog"=>"large",  "cat"=>"medium",  "mouse"=>"small");
print_r($animals);
//Array ( [dog] => large [cat] => medium [mouse] => small )

rsort($animals);
print_r($animals);
//Array ( [0] => small [1] => medium [2] => large )

Use KSORT() or KRSORT() to preserve associative keys.

<?php 

error_reporting(E_ALL); 

class test{ 

public $public; 

private $private; 

protected $protected; 

static $instance; 

public function __construct(){ 

$this->public = 'public <br>'; 

$this->private = 'private <br>'; 

$this->protected = 'protected <br>'; 

} 

static function tank(){ 

if (!isset(self::$instance[get_class()])) 

{ 

$c = get_class(); 

self::$instance = new $c; 

} 

return self::$instance; 

} 

public function pub_function() { 

echo "you request public function<br>"; 

echo $this->public; 

echo $this->private; //private,内部可以调用 

echo $this->protected; //protected,内部可以调用 

$this->pri_function(); //private方法，内部可以调用 

$this->pro_function(); //protected方法，内部可以调用 

} 

protected function pro_function(){ 

echo "you request protected function<br>"; 

} 

private function pri_function(){ 

echo "you request private function<br>"; 

} 

} 

$test = test::tank(); 

echo $test->public; 

echo $test->private; //Fatal error: Cannot access private property test::$private 

echo $test->protected; //Fatal error: Cannot access protected property test::$protected 

$test->pub_function(); 

$test->pro_function(); //Fatal error: Call to protected method test::pro_function() from context 

$test->pri_function(); //Fatal error: Call to private method test::pri_function() from context 

?> 

<?php error_reporting(E_ALL);  class test{  public $public;  private $private;  protected $protected;  static $instance;  public  function __construct(){  $this->public    = 'public     <br>';  $this->private   = 'private    <br>';  $this->protected = 'protected  <br>';  }  static function tank(){  if (!isset(self::$instance[get_class()]))  {  $c = get_class();  self::$instance = new $c;  }   return self::$instance;  }       public function pub_function() {  echo "you request public function<br>";  echo $this->public;  echo $this->private;        //private,内部可以调用  echo $this->protected;      //protected,内部可以调用  $this->pri_function();      //private方法，内部可以调用  $this->pro_function();      //protected方法，内部可以调用  }  protected  function pro_function(){  echo "you request protected function<br>";  }  private function pri_function(){  echo "you request private function<br>";  } }  $test = test::tank(); echo $test->public; echo $test->private;    //Fatal error: Cannot access private property test::$private echo $test->protected;  //Fatal error: Cannot access protected property test::$protected $test->pub_function(); $test->pro_function();  //Fatal error: Call to protected method test::pro_function() from context $test->pri_function();  //Fatal error: Call to private method test::pri_function() from context  ?>

从上面的例子中，我们可以看出，
public: 可以class内部调用，可以实例化调用。
private: 可以class内部调用，实例化调用报错。
protected： 可以class内部调用，实例化调用报错。

<?php 

class test{ 

public $public; 

private $private; 

protected $protected; 

static $instance; 

public function __construct(){ 

$this->public = 'public <br>'; 

$this->private = 'private <br>'; 

$this->protected = 'protected <br>'; 

} 

protected function tank(){ //私有方法不能继承，换成public,protected 

if (!isset(self::$instance[get_class()])) 

{ 

$c = get_class(); 

self::$instance = new $c; 

} 

return self::$instance; 

} 

public function pub_function() { 

echo "you request public function<br>"; 

echo $this->public; 

} 

protected function pro_function(){ 

echo "you request protected function<br>"; 

echo $this->protected; 

} 

private function pri_function(){ 

echo "you request private function<br>"; 

echo $this->private; 

} 

} 

class test1 extends test{ 

public function __construct(){ 

parent::tank(); 

parent::__construct(); 

} 

public function tank(){ 

echo $this->public; 

echo $this->private; //Notice: Undefined property: test1::$private 

echo $this->protected; 

$this->pub_function(); 

$this->pro_function(); 

$this->pri_function(); //Fatal error: Call to private method test::pri_function() from context 'test1' 

} 

public function pro_extends_function(){ 

echo "you request extends_protected function<br>"; 

} 

public function pri_extends_function(){ 

echo "you request extends_private function<br>"; 

} 

} 

error_reporting(E_ALL); 

$test = new test1(); 

$test -> tank(); //子类和父类有相同名字的属性和方法，实例化子类时，子类的中的属性和方法会盖掉父类的。 

?>