<?php

$a = array ('test' => 1, 'hello' => NULL);

var_dump( isset ($a['test') ); // TRUE
var_dump( isset ($a['foo') ); // FALSE
var_dump( isset ($a['hello') ); // FALSE

// 'hello' 等于 NULL，所以被认为是未赋值的。
// 如果想检测 NULL 键值，可以试试下边的方法。
var_dump( array_key_exists('hello', $a) ); // TRUE

?>

<?php
    class Test{
        const STATUS_NORMAL  = 0;
        public static $count = 1;
        public static function echoConst(){
            //函数内部调用常量
            echo self::STATUS_NORMAL;
        }
        public static function strPrint(){
            echo 'this is strPrint static function \n\n';
        }
        public static function addCount(){函数内部调用函数
            //函数内部调用类变量
            self::$count += 1;
        }
        public function staticFuncInvoke(){
　　　　　　　　//函数内部调用静态方法
            self::strPrint();
        }
    }
    
    $test = new Test();
    $test->addCount();
    $test->addCount();
    $test->addCount();

    //调用类常量
    echo $test::STATUS_NORMAL;
    echo Test::STATUS_NORMAL;
    //调用静态变量
    echo $test::$count;
    echo Test::$count;
    //调用静态方法
    $test->staticFuncInvoke();
    Test::staticFuncInvoke();
?>

<?php

    $global_book = "编程测试书籍456";

    function test() {
        echo "test\n\n";
    }

    class MyTest 
    {
        protected $book = "编程测试书籍";

        function __construct() {
            //调用全局方法
            test();
            //调用全局变量（两种方法）
            $this->print_ok($GLOBALS['global_book']);
            global $global_book;
            $this->print_ok($global_book);

            //调用局部变量（仅此一种方法）
            $temp = "good";
            $this->print_ok($temp);
            //调用类方法（仅此一种方法）
            $this->print_ok($this->get_name());
            //调用类变量（仅此一种方法）
            $this->print_ok($this->book);
        }

        private function print_ok($str) {
            echo "\n";
            echo $str;
            echo "\n\n";
        }

        private function get_name() {
            return "ivar1001";
        }
    }

    new MyTest();
?>

<?php
    $son_search_option = array();  
    //正确的添加
    $search_option[] = " accounts_receivable_id in $id_set";

    //另一种错误的添加
    $search_option[] = array( 
        accounts_receivable_id in $id_set"
    );
?>

<?php
    $result = strpos("Hello world!","world");
    if($result == false)
        echo "cuowu";
    else 
        echo "zhegnque";
?>

<?php
    echo str_replace("world","Shanghai","Hello world!");
?>

<?php
    $name = "good";
    $str = ‘$name dook’;
    echo $str;    
?>

<?php
    $name = "good";
    echo '$name \n\n';
    $str = "$name dook";
    echo $str;
?>

<?php
    
    $fruits = array(
        "apple" => 5,
        "orange" => 6,
        "ice" => 3
    );
    $jsonStr = json_encode($fruits);
    $obj = json_decode($jsonStr, true);    
    var_dump($obj);

?>

<?php
    $str = "Hello WorldWorld";
    echo $str . "\n";
    echo rtrim($str,"World!");    
?>

<?php
    $a = "";
    if($a)
        echo "good";
    else
        echo "wrong";
?>