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博文笔记

PHP小demo

创建时间：2014-10-22 投稿人： 浏览次数：144

1.  compact 函数

$a = "123";
$b = "456";

$com = compact("a","b");
var_dump($com);

array(2) {

  ["a"]=>
  string(3) "123"
  ["b"]=>
  string(3) "456"
}


2. array_chunk 函数

<?php
$count=10;
while($count--) {
    $arr[]= $count;
}
$ret = array_chunk($arr, 4); 
print_r($ret);

Array
(
    [0] => Array
        (
            [0] => 9
            [1] => 8
            [2] => 7
            [3] => 6
        )
    [1] => Array
        (
            [0] => 5
            [1] => 4
            [2] => 3
            [3] => 2
        )
    [2] => Array
        (
            [0] => 1
            [1] => 0
        )
)


3. date 函数

echo date("Ymd", time());


4.  empty 函数 

$str1 = ""; 
$str2 = 0;
$arr1 = array();
$arr2 = array(1,2,3);
echo $arr1 ? "Y" : "N";
echo $arr2 ? "Y" : "N";
echo null ? "Y" : "N";
echo empty($str1) ? "Y":"N";
echo empty($str2) ? "Y":"N";

NYNYY


5.  exit 语句 

echo "before exit
";
exit;
echo "after exit
";

before exit


6. array_shift 函数


7. array_pop 函数


8. json_encode 、json_decode函数

$json_data = array("status" => 0, "msg" => "账号错误");
$str = json_encode($json_data);
echo $str;


{"status":0,"msg":"u8d26u53f7u9519u8bef"} 

注：json_encode过程中自动进行类型转换

9.  for + &循环中改变变量

$arr = array(
    array("id" => 1, "name" => "A", "address" => "BJ"),
    array("id" => 1, "name" => "A", "address" => "BJ"),
);
foreach($arr as &$k) { //这里使用&可以直接修改数组中的每个变量
    $k["gender"] = "male";
}
print_r($arr);



Array
(
    [0] => Array
        (
            [id] => 1
            [name] => A
            [address] => BJ
            [gender] => male
        )


    [1] => Array
        (
            [id] => 1
            [name] => A
            [address] => BJ
            [gender] => male
        )


)


10.  二维数组的转置

$user = array(
        0 => array(
            "id"    => 1,
            "name"  => "张三",
            "email" => "zhangsan@sina.com",
            ),  
        1 => array(
            "id"    => 2,
            "name"  => "李四",
            "email" => "lisi@163.com",
            ),  
        2 => array(
            "id"    => 5,
            "name"  => "王五",
            "email" => "10000@qq.com",
            ),  
        );  
$ids = array_map("array_shift", $user); //注意array_map的用法 array_map("callback", array)
var_dump($ids);
//php5.4无array_column函数
//$names = array_column($user, "name");
$names = array_reduce($user, create_function("$v,$w", "$v[$w["id"]]=$w["name"];return $v;"));  
var_dump($names);


array(3) {
  [0]=>
  int(1)
  [1]=>
  int(2)
  [2]=>
  int(5)
}
array(3) {
  [1]=>
  string(6) "张三"
  [2]=>
  string(6) "李四"
  [5]=>
  string(6) "王五"
}


11. 函数调用

function add($a, $b) { //非类，不能用public等限定符修饰
    return $a+$b;
}
echo add(1,2);

3

class A { 
    function func() {
        echo get_class()."
";
    }   
}

$obj = new A();
$obj->func();


A


class Base {
    protected function func1() {
        echo "Base func1
";
    }   
    public function func2() {
        echo "Base func2
";
    }   
}

class Sub extends Base{
}

$obj = new Sub();
//$obj->func1(); // Call to protected method Base::func1() from context ""
$obj->func2();


12.  字符串转整型、字符串比较

echo intval(10/3)."
";
echo intval("1.2")."
";
echo intval("0130Z110BF34")."
";
$str = "0130Z110BF34";
if ($str != "000000") {
    echo "error
";
}
3
1
130
error


13.  接口的实现、类的继承

//默认不能自动加载其他文件的类、接口 
interface IStu {
    //接口不能有变量
    //    public $var1 = "var1";
    //    public $var2 = "var2";

    /*函数名不需要abstract修饰*/
    function draw();

    //接口不能有实现的函数
    /*
       function learn() {
       echo "learning...
";
       }
     */
     function write();
     function pianno();
     function chess();
}


//这里不能有public修饰类，为什么？
class Student {
    public $school = "china";
    //不要使用如下形式，会发生嵌套初始化
//    public function __construct($name = "good") {
//        $cls = Ucfirst($name)."Student";
//        return new GoodStudent();
//        return new $cls(); 
//    }
    public static function getInstance($name) {
        $cls = Ucfirst($name)."Student";
        return new $cls();
    }

public function draw() {
        echo "draw something...
";
    }
}


//这里要加上abstract由于BJ没有实现所有的接口函数
abstract class BJ  extends Student implements IStu {
    public $school = "bj";
    public function chess() {
        echo "I chess in BJ
";
    }
}




class GoodStudent extends BJ {
    public function write() {
        echo "Hi, I am in ".$this->school."
";
        echo "good write
";
    }


    public function pianno() {
        echo "good pianno
";
    }
}


class BadStudent extends Student implements IStu{
    public function write() {
        echo "bad write
";
    }


    public function pianno() {
        echo "bad pianno
";
    }


    public function chess() {
        echo "bad chess
";
    }
}

//$obj = new Student("good");
//$obj = new GoodStudent();
$obj = Student::getInstance("good");
$obj->write();
$obj->chess();
Hi, I am in bj
good write
I chess in BJ 

interface IStu {
    //接口不能有变量
    //public $var1 = "var1";
    //public $var2 = "var2";

    /*函数名不需要abstract修饰*/
    function draw();

    //接口不能有实现的函数
    /*  
       function learn() {
       echo "learning...
";
       }
     */
}


14.  isset 函数

$arr = array(
    "TX" => array("TX-a" => "b", "TX-b" => "c"),
    "TY" => "c",
    );  
var_dump(isset($arr["TX"]) && isset($arr["TX"]["TX-a"])); 
var_dump(isset($arr["TX"], $arr["TX"]["TX-a"])); //同上，更简洁
var_dump(isset($arr["TX"], $arr["TX"]["TX-c"]));
var_dump(isset($arr["TZ"], $arr["TX"]["TX-c"]));
var_dump(isset($arr["TZ"]));

bool(true)
bool(true)
bool(false)
bool(false)
bool(false)

15. mb_函数

$cardno = "3中—100901100322203";
echo substr($cardno, 0, 4) . "********" . substr($cardno, -4, 4)."
";
echo mb_substr($cardno, 0, 4, "utf-8") . "********" . mb_substr($cardno, -4, 4)."
";


3中********2203
3中—1********2203


$str = "西安世纪JAVA编程思想设计模式之禅算法之道";
echo strlen($str)."  ".strlen($str)."  ". mb_strlen($str,"UTF-8")."
"; //utf-8, utf8, UTF-8都可以？
$str = mb_substr($str, 0, 19, "utf-8");
echo strlen($str)."  ".strlen($str)."  ". mb_strlen($str,"utf-8")."
";
58  58  22
49  49  19

注：需要PHP中mbstring扩展的支持


16. simplexml_load_string 函数

$obj = @simplexml_load_string("abc"); //仅对xml格式的字符串进行解析，否则返回false
var_dump($obj);
$obj = @simplexml_load_string("<t>a</t>"); //注意解析出的每个元素是一个对象，对象里面是一个string
var_dump($obj);


bool(false)
object(SimpleXMLElement)#1 (1) { 
  [0]=>
  string(1) "a"
} 


$xml = simplexml_load_string("<root><number>1</number></root>"); 
echo $xml->asXml(). "

"; //自动加上xml头

<?xml version="1.0"?>
<root><number>1</number></root>

17.  null比较

$ret = null;
echo $ret === false ? "false" : "not false";
echo " ";
echo $ret == false ? "false" : "not false";

$ret = null;
echo $ret === false ? "false" : "not false"; //not false
echo "
"; 
echo $ret == false ? "false" : "not false"; //false

18. parse_ini_file 函数 

$ini_path = "abc.ini";  
$ini = parse_ini_file($ini_path);
print_r($ini);


abc.ini的内容

[first]
A = 1
B = 2

结果

Array
(
    [A] => 1
    [B] => 2
)

19. mysql-pdo进行数据库操作

$dsn = "mysql:host=localhost; dbname=test";
$username = "root";
$passwd = "doupei";
try {
    $dbx = new PDO($dsn, $username, $passwd);
    echo "Connected to db successfully!"."
";
    /*  
       $sql = "select * from table_a where id = 2";
       $res = $dbx->query($sql);
       foreach($res  as $row) {
       print $row["id"]."	";
       print $row["name"]."	";
       }
     */
    $name = "tom"; $id = 100;
    $sql = "insert into table_a(id, name) values(:id, :name)";
    $stmt = $dbx->prepare($sql);
    $stmt->bindParam(":id", $id);
    $stmt->bindParam(":name", $name);
    $stmt->execute();
} catch (Exception $e) {
    echo "Faild to connect to db!"."
";
    echo $e->getMessage();
}

20.  argv, argc变量 

<?php
print_r($argv);
echo "
$argc
";


命令行执行：php testPhpArgv.php  a b c d

Array
(
    [0] => testPhpArgv.php
    [1] => a
    [2] => b
    [3] => c
    [4] => d
)

5

21.  整数的判断

$arr = array(-1, -1.23, 0, 1, 2, 2.4, "12.0", "15");
foreach ($arr as $val) {
    //if (!preg_match("/^+?[1-9][0-9]*$/", $val)) {
    //整数的判断
    if (!is_int(intval($val)) || intval($val) <= 0){ 
        echo $val. "不是正整数"."
";
    }   
}
$brr = array("-1", -1, "a1", "1a", "45", "1abc4", "-0.1111", "-0.12a");
foreach ($brr as $val) {
    //对应的整数值
    echo $val . "对应整数 ". intval($val) . "
";
}

-1不是正整数
-1.23不是正整数
0不是正整数
-1对应整数 -1
-1对应整数 -1
a1对应整数 0
1a对应整数 1
45对应整数 45
1abc4对应整数 1
-0.1111对应整数 0
-0.12a对应整数 0


22. static变量

class Student {
    public static $address = "bj";
    public function __coustruct() {
        Student::$address = "sh";
    }   

}

$t = new Student();
echo Student::$address; //bj而不是sh


23. array  unset array_filter 函数 

$arr = array(3=>"a",4=>"b",5=>"c",2=>"d",0=>"e");
foreach ($arr as $k => $v) {
    if ($k==3) {
        unset($arr[$k]);
    }
}
echo count($arr)."
";

function filter($val) {
    return $val;
}
array_filter($arr, "filter");
echo count($arr)."
";

unset($arr[2]);
echo count($arr)."
";

function odd($var)
{
    // returns whether the input integer is odd
    return($var & 1);
}

function even($var)
{
    // returns whether the input integer is even
    return(!($var & 1));
}

$array1 = array("a"=>1, "b"=>2, "c"=>3, "d"=>4, "e"=>5);
$array2 = array(6, 7, 8, 9, 10, 11, 12);

echo "Odd :
";
print_r(array_filter($array1, "odd"));
echo "Even:
";
print_r(array_filter($array2, "even"));

4
4
3
Odd :
Array
(
    [a] => 1
    [c] => 3
    [e] => 5
)
Even:
Array
(
    [0] => 6
    [2] => 8
    [4] => 10
    [6] => 12
)

24.  字符编码

$str = "AC,,,|BD1234_XXXzz"; //对应的UTF8、GBK编码相同
$reqstr = iconv("UTF-8", "GBK", $str);
echo $reqstr."
";
$reqstr = iconv("GBK", "UTF-8", $str);
echo $reqstr."
";

AC,,,|BD1234_XXXzz

AC,,,|BD1234_XXXzz

25. array_merge 和 array的加法

$a = array(3 => "a", 4 => "b", 5 => "c");
$b = array(3 => "aa", 4 => "b");
$c = array_merge($a, $b);
print_r($c);
$d = $b + $a; 
print_r($d);

Array
(
    [0] => a
    [1] => b
    [2] => c
    [3] => aa
    [4] => b
)
Array
(
    [3] => aa
    [4] => b
    [5] => c
)


26. array_combine 等价于array_merge 再赋值 

$arr = array("x2","x3","x3");
$arr[] = "xw5";
array_combine($arr,array(8,9));
print_r($arr);

PHP Warning:  array_combine(): Both parameters should have an equal number of elements x.php on line 4
Array
(
    [0] => x2
    [1] => x3
    [2] => x3
    [3] => xw5
)


27. array_slice 函数

$arr = array("A"=>1, "B"=>2, "C"=>3);
$sub = array_slice($arr, 0, 2); 
var_dump($sub);
array(2) {
  ["A"]=>
  int(1)
  ["B"]=>
  int(2)
}


28. array_unique 函数

$arr = array("a","a","c","d");
$brr = array_unique($arr);
print_r($arr); //$arr本身未变化
print_r($brr);

Array
(
    [0] => a
    [1] => a
    [2] => c
    [3] => d
)
Array
(
    [0] => a
    [2] => c
    [3] => d
)
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