PHP小demo
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());
$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
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;
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();
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
";
}31
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 bjgood 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—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);
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);
[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
$arr = array(3=>"a",4=>"b",5=>"c",2=>"d",0=>"e");
foreach ($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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