21天学通PHP PDF 清晰扫描第2版

<?php
echo "Hello World\n"; 
?>

php D:/script/hello.php
Hello World

for i=1;i<arr.length;i++
    target=arr[i]
    if arr[i]%2==1
        j=i-1
        while j>=0&&arr[j]%2==0
            arr[j+1]=arr[j]
            j--
        arr[j+1]=target

<?php
$arr=array(1,2,3,4,5,6,7,8,9,10);
function reOrderArray($arr){
        $length=count($arr);
        //从前往后遍历
        for($i=1;$i<$length;$i++){
                //判断当前元素是奇数
                $target=$arr[$i];
                if($target%2==1){
                        //从后往前遍历,如果有偶数就往后移动一位
                        $j=$i-1;
                        while($j>=0 && $arr[$j]%2==0){
                                $arr[$j+1]=$arr[$j];
                                $j--;
                        }   
                        //把奇数插入位置
                        $arr[$j+1]=$target;
                }   
        }   
        return $arr;
}
 
$arr2=reOrderArray($arr);
var_dump($arr2);

array(10) {
  [0]=>
  int(1)
  [1]=>
  int(3)
  [2]=>
  int(5)
  [3]=>
  int(7)
  [4]=>
  int(9)
  [5]=>
  int(2)
  [6]=>
  int(4)
  [7]=>
  int(6)
  [8]=>
  int(8)
  [9]=>
  int(10)
}

<?php
//调整数组，使奇数位于偶数前面

function reorder($arr){
        $length = count($arr);
        $begin = 0;
        $end = $length - 1;
        while($begin < $end){
                //向后移动begin，直到它指到偶数
                while(($begin < $end) && (($arr[$end] & 0x1) != 0)){
                        $begin++;
                }

                //向前移动end，指到它指到奇数
                while(($begin < $end) && (($arr[$end] & 0x1) == 0)){
                        $end--;
                }

                if($begin < $end){
                        $temp = $arr[$begin];
                        $arr[$begin] = $arr[$end];
                        $arr[$end] = $temp;
                }
        }
        return $arr;
}

$arr = [1,2,3,4,5,6,7,8];
var_dump(reorder($arr));

<?php
//调整数组，使奇数位于偶数前面

function reorder($arr, $func){
        $length = count($arr);
        $begin = 0;
        $end = $length - 1;
        while($begin < $end){
                //向后移动begin，直到它指到偶数
                while(($begin < $end) && (!$func($arr[$begin]))){
                        $begin++;
                }

                //向前移动end，指到它指到奇数
                while(($begin < $end) && ($func($arr[$end]))){
                        $end--;
                }

                if($begin < $end){
                        $temp = $arr[$begin];
                        $arr[$begin] = $arr[$end];
                        $arr[$end] = $temp;
                }
        }
        return $arr;
}

$func = function($condition){
        $flag = ($condition & 0x1) == 0;
        return $flag;
};

$arr = [1,2,3,4,5,6,7,8];
var_dump(reorder($arr, $func));

# @Date    : 2017-11-15 13:18:34
# @Author  : 师兵范 (shibingfan@163.com)
 
#常用MySQL数据库命令
+------------+----------------+
| COMD       |   DESCRIPTION  | 
+------------+----------------+
|ALTER       |修改            |
|BACKUP      |备份            | 
|\C          |取消输入        | 
|CREATE      |创建            | 
|DELETE      |删除行          | 
|DESCRIBE    |表结构          | 
|DROP        |删除            | 
|EXIT(CTRL-C)|退出            | 
|GRANT       |修改权限        | 
|HELP(\h,\?) |帮助            | 
|INSERT      |插入            | 
|LOCK        |锁住            | 
|QUIT(\q)    |退出            | 
|RENAME      |重命名          | 
|SHOW        |项目说明        | 
|SOURCE      |从文件名执行命令| 
|STATUS(\s)  |显示当前状态    | 
|TRUNCATE    |清空表          | 
|UNLOCK      |解锁表          | 
|UPDATE      |更新数据        | 
|USE         |打开数据库      | 
+------------+----------------+
#显示已有数据库
mysql> SHOW databaseS; 
+--------------------+
| Database           |
+--------------------+
| information_schema |
| drupal7            |
| mysql              |
| northwind          |
| performance_schema |
| shibingfan         |
| sys                |
| testdb             |
+--------------------+
8 rows in set (0.06 sec)
#创建数据库
mysql> CREATE DATABASE publications;
Query OK, 1 row affected (0.03 sec)
#使用数据库
mysql> USE publications;
Database changed
#数据库授权
mysql> GRANT ALL ON publications.* TO 'shibingfan'@'localhost' IDENTIFIED BY 'shibingfan';
Query OK, 0 rows affected, 1 warning (0.00 sec)
#创建数据库表
mysql> CREATE TABLE classics(
    -> author VARCHAR(128),
    -> title VARCHAR(128),
    -> type VARCHAR(16),
    -> YEAR char(4))ENGINE  MyISAM;
Query OK, 0 rows affected (0.08 sec)
#查询表结构
mysql> DESCRIBE classics;
+--------+--------------+------+-----+---------+-------+
| Field  | Type         | Null | Key | Default | Extra |
+--------+--------------+------+-----+---------+-------+
| author | varchar(128) | YES  |     | NULL    |       |
| title  | varchar(128) | YES  |     | NULL    |       |
| type   | varchar(16)  | YES  |     | NULL    |       |
| YEAR   | char(4)      | YES  |     | NULL    |       |
+--------+--------------+------+-----+---------+-------+
4 rows in set (0.02 sec)
#数据类型
CHAR(n)   VARCHAR(n)
BINARY(n) VARBINARY(n)
TEXT(n)   TINYTEXT(n)   MEDIUMTEXT(n)  LONGTEXT(n)
TINYBLOB(n)  BLOB(n)
TINYINT   SMALLINT      MEDIUMINT      INT/INTEGER    BIGINT
FLOAT     DOUBLE/REAL
DATETIME  DATE          TIMESTAMP      TIME           YEAR
INT UNSIGNED,  NOT NULL,  AUTO_INCREMENT,  KEY
#添加表列id
mysql> ALTER TABLE classics ADD id INT UNSIGNED NOT NULL AUTO_INCREMENT KEY;
Query OK, 0 rows affected (0.06 sec)
Records: 0  Duplicates: 0  Warnings: 0
#删除表列
mysql> ALTER TABLE classics DROP id;
Query OK, 0 rows affected (0.08 sec)
Records: 0  Duplicates: 0  Warnings: 0
#向表中添加数据
mysql> INSERT INTO classics(author,title,type,year)VALUES('Shibingfan', 'LEARN MYSQL', 'EDUCATION', '1887');
Query OK, 1 row affected (0.00 sec)
#重命名表
mysql> ALTER TABLE classics RENAME mytable ;
Query OK, 0 rows affected (0.02 sec)
#改变列数据类型
mysql> ALTER TABLE mytable MODIFY year SMALLINT;
Query OK, 5 rows affected (0.08 sec)
#添加新列
mysql> ALTER TABLE mytable ADD pages SMALLINT UNSIGNED;
Query OK, 5 rows affected (0.08 sec)
#重命名列
mysql> ALTER TABLE mytable CHANGE type category VARCHAR(16);
Query OK, 0 rows affected (0.31 sec)
#删除列
mysql> ALTER TABLE mytable DROP pages;//DROP命令不可逆
Query OK, 5 rows affected (0.33 sec)
#删除表
mysql> DROP TABLE mytable;
Query OK, 0 rows affected (0.02 sec)
#创建索引
mysql> ALTER TABLE mytable ADD INDEX(author(20));
mysql> CREATE INDEX author ON mytable(author(20));//也可在创建表时添加索引
Query OK, 5 rows affected (0.08 sec)
#创建全文索引
mysql> ALTER TABLE mytable ENGINE = MyISAM;		//将表转换为MyISAM
mysql> ALTER TABLE mytable ADD FULLTEXT(author,title);
#数据库查询
SELECT * FROM mytable;
SELECT author,title FROM mytable;
SELECT COUNT(*) FROM mytable;			//计数
SELECT DISTINCT author FROM mytable; 	//去重
DELETE FROM mytable WHERE title = 'LEARN MYSQL';
SELECT * FROM mytable WHERE author='Shibingfan';
SELECT * FROM mytable WHERE author LIKE "Shi%";		//like关键字，模糊匹配
SELECT author FROM mytable LIMIT 3;					//LIMIT关键字，限定返回的行数
SELECT author FROM mytable LIMIT 3，1;				//LIMIT关键字，限定从表的什么位置开始返回多少行
SELECT * FROM mytable WHERE MATCH(author,title) AGAINST('Shi'); //自然语言在FULLTEXT索引列上搜索
SELECT * FROM mytable WHERE MATCH(author,title) AGAINST('+Shi -bing' IN BOLLEAN MODE);//布尔模式下搜索
UPDATE mytable SET author='Shibf' WHERE author='shibingfan'; 	//更新数据
SELECT author,title FROM mytable ORDER BY author;				//排序
SELECT category,COUNT(author) FROM mytable GROUP BY category;	//分组
#连接表，新建customers表
SELECT * FROM mytable,customers WHERE mytable.isbn=customers.isbn;
SELECT * FROM customers NATURAL JOIN mytable;		//自然连接，将相同列名的表自动合并
SELECT * FROM customers JOIN mytable ON mytable.isbn=customers.isbn;
SELECT author,title FROM mytable AS au,ti;			//AS重命名
SELECT * FROM mytable,customers WHERE mytable.isbn=customers.isbn AND author='shibingfan';
 
 
#事物
#事物存储引擎InnoDB
mysql> CREATE TABLE accounts(number INT, balance FLOAT, PRIMARY KEY(number))ENGINE InnoDB;
mysql> INSERT INTO accounts(number,balance) VALUES(12345,1025.50);
mysql> INSERT INTO accounts(number,balance) VALUES(67890,140.00);
mysql> SELECT * FROM accounts ;
+--------+---------+
| number | balance |
+--------+---------+
|  12345 |  1025.5 |
|  67890 |     140 |
+--------+---------+
#事物处理BEGIN, COMMIT, ROOLBACK
mysql> BEGIN;
mysql> UPDATE accounts SET balance=balance+25.11 WHERE number=12345;
mysql> COMMIT; 		//确认提交，数据库发生更改
mysql> ROLLBACK;	//回滚操作，数据库恢复到BEGIN之前的状态
#使用EXPLAIN，得到查询快照，进而对查询进行优化
mysql> EXPLAIN SELECT * FROM accounts WHERE number='12345';
+----+-------------+----------+------------+-------+---------------+---------+---------+-------+------+----------+-------+
| id | select_type | table    | partitions | type  | possible_keys | key     | key_len | ref   | rows | filtered | Extra |
+----+-------------+----------+------------+-------+---------------+---------+---------+-------+------+----------+-------+
|  1 | SIMPLE      | accounts | NULL       | const | PRIMARY       | PRIMARY | 4       | const |    1 |   100.00 | NULL  |
+----+-------------+----------+------------+-------+---------------+---------+---------+-------+------+----------+-------+
#备份和恢复
mysql> LOCK TABLES mytable READ,accounts READ;		//锁定表UNLOCK TABLES;
mysql> mysqldump -u user -ppassword publications;
mysql> mysqldump -u user -ppassword publications mytable > mytable.sql;
mysql> mysqldump -u user -ppassword publications --all-database > all_db.sql;
mysql> mysqldump -u user -ppassword < all_db.sql;
mysql> mysqldump -u user -ppassword -D publications < mytable.sql;

function printNum($max, $caller)
{
  for ($i=0; $i<$max; $i++ ) {
    echo "调度者:" . $caller . " 打印:" . $i . PHP_EOL;
  }
}
 
printNum(3, "caller1");
printNum(3, "caller2");
 
# output
调度者:caller1 打印:0
调度者:caller1 打印:1
调度者:caller1 打印:2
调度者:caller2 打印:0
调度者:caller2 打印:1
调度者:caller2 打印:2

# 本代码手动调整了进程执行代码的顺序，当然本代码实现不用协程也可以，只是利用本流程说明协程作用
# 生成器给了我们函数中断，协程[生成器send]给了我们重新唤起生成器函数的能力
function printNumWithGen($max)
{
  for ($i=0; $i<$max; $i++ ) {
    $res = yield $i;
    echo $res;
  }
}
 
$gen1 = printNumWithGen(3);
$gen2 = printNumWithGen(3);
 
// 手动执行caller1 再 caller2
$gen1->send("调度者: caller1 打印:" . $gen1->current() . PHP_EOL);
$gen2->send("调度者: caller2 打印:" . $gen2->current() . PHP_EOL);
 
// 手动执行caller1 再 caller2
$gen1->send("调度者: caller1 打印:" . $gen1->current() . PHP_EOL);
$gen2->send("调度者: caller2 打印:" . $gen2->current() . PHP_EOL);
 
// 手动执行caller2 再 caller1
$gen2->send("调度者: caller2 打印:" . $gen2->current() . PHP_EOL);
$gen1->send("调度者: caller1 打印:" . $gen1->current() . PHP_EOL);
 
# output
调度者: caller1 打印:0
调度者: caller2 打印:0
调度者: caller1 打印:1
调度者: caller2 打印:1
调度者: caller2 打印:2
调度者: caller1 打印:2

<?php
class MyIterator implements Iterator
{
 private $var = array();
 public function __construct($array)
 {
  if (is_array($array)) {
   $this->var = $array;
  }
 }
 public function rewind() {
  echo "rewinding\n";
  reset($this->var);
 }
 public function current() {
  $var = current($this->var);
  echo "current: $var\n";
  return $var;
 }
 public function key() {
  $var = key($this->var);
  echo "key: $var\n";
  return $var;
 }
 public function next() {
  $var = next($this->var);
  echo "next: $var\n";
  return $var;
 }
 public function valid() {
  $var = $this->current() !== false;
  echo "valid: {$var}\n";
  return $var;
 }
}
$values = array(1,2,3);
$it = new MyIterator($values);
foreach ($it as $a => $b) {
 print "$a: $b\n";
}

<?php
function xrange($start, $end, $step = 1) {
 for ($i = $start; $i <= $end; $i += $step) {
  yield $i;
 }
}
foreach (xrange(1, 1000000) as $num) {
 echo $num, "\n";
}

/**
 * Task任务类
 */
class Task
{
 protected $taskId;
 protected $coroutine;
 protected $beforeFirstYield = true;
 protected $sendValue;

 /**
  * Task constructor.
  * @param $taskId
  * @param Generator $coroutine
  */
 public function __construct($taskId, Generator $coroutine)
 {
  $this->taskId = $taskId;
  $this->coroutine = $coroutine;
 }
 /**
  * 获取当前的Task的ID
  * 
  * @return mixed
  */
 public function getTaskId()
 {
  return $this->taskId;
 }
 /**
  * 判断Task执行完毕了没有
  * 
  * @return bool
  */
 public function isFinished()
 {
  return !$this->coroutine->valid();
 }
 /**
  * 设置下次要传给协程的值，比如 $id = (yield $xxxx)，这个值就给了$id了
  * 
  * @param $value
  */
 public function setSendValue($value)
 {
  $this->sendValue = $value;
 }
 /**
  * 运行任务
  * 
  * @return mixed
  */
 public function run()
 {
  // 这里要注意，生成器的开始会reset，所以第一个值要用current获取
  if ($this->beforeFirstYield) {
   $this->beforeFirstYield = false;
   return $this->coroutine->current();
  } else {
   // 我们说过了，用send去调用一个生成器
   $retval = $this->coroutine->send($this->sendValue);
   $this->sendValue = null;
   return $retval;
  }
 }
}

/**
 * Class Scheduler
 */
Class Scheduler
{
 /**
  * @var SplQueue
  */
 protected $taskQueue;
 /**
  * @var int
  */
 protected $tid = 0;

 /**
  * Scheduler constructor.
  */
 public function __construct()
 {
  /* 原理就是维护了一个队列，
   * 前面说过，从编程角度上看，协程的思想本质上就是控制流的主动让出（yield）和恢复（resume）机制
   * */
  $this->taskQueue = new SplQueue();
 }
 /**
  * 增加一个任务
  *
  * @param Generator $task
  * @return int
  */
 public function addTask(Generator $task)
 {
  $tid = $this->tid;
  $task = new Task($tid, $task);
  $this->taskQueue->enqueue($task);
  $this->tid++;
  return $tid;
 }
 /**
  * 把任务进入队列
  *
  * @param Task $task
  */
 public function schedule(Task $task)
 {
  $this->taskQueue->enqueue($task);
 }
 /**
  * 运行调度器
  */
 public function run()
 {
  while (!$this->taskQueue->isEmpty()) {
   // 任务出队
   $task = $this->taskQueue->dequeue();
   $res = $task->run(); // 运行任务直到 yield

   if (!$task->isFinished()) {
    $this->schedule($task); // 任务如果还没完全执行完毕，入队等下次执行
   }
  }
 }
}

<?php
function task1() {
 for ($i = 1; $i <= 10; ++$i) {
  echo "This is task 1 iteration $i.\n";
  yield; // 主动让出CPU的执行权
 }
}
function task2() {
 for ($i = 1; $i <= 5; ++$i) {
  echo "This is task 2 iteration $i.\n";
  yield; // 主动让出CPU的执行权
 }
}
$scheduler = new Scheduler; // 实例化一个调度器
$scheduler->newTask(task1()); // 添加不同的闭包函数作为任务
$scheduler->newTask(task2());
$scheduler->run();

function task1() {
  /* 这里有一个远程任务，需要耗时10s，可能是一个远程机器抓取分析远程网址的任务，我们只要提交最后去远程机器拿结果就行了 */
  remote_task_commit();
  // 这时候请求发出后，我们不要在这里等，主动让出CPU的执行权给task2运行，他不依赖这个结果
  yield;
  yield (remote_task_receive());
  ...
} 
function task2() {
 for ($i = 1; $i <= 5; ++$i) {
  echo "This is task 2 iteration $i.\n";
  yield; // 主动让出CPU的执行权
 }
}

<?php
function echoTimes($msg, $max) {
 for ($i = 1; $i <= $max; ++$i) {
  echo "$msg iteration $i\n";
  yield;
 }
}
function task() {
 echoTimes('foo', 10); // print foo ten times
 echo "---\n";
 echoTimes('bar', 5); // print bar five times
 yield; // force it to be a coroutine
}
$scheduler = new Scheduler;
$scheduler->newTask(task());
$scheduler->run();

 /**
  * Task constructor.
  * @param $taskId
  * @param Generator $coroutine
  */
 public function __construct($taskId, Generator $coroutine)
 {
  $this->taskId = $taskId;
  // $this->coroutine = $coroutine;
  // 换成这个，实际Task->run的就是stackedCoroutine这个函数，不是$coroutine保存的闭包函数了
  $this->coroutine = stackedCoroutine($coroutine); 
 }

/**
 * @param Generator $gen
 */
function stackedCoroutine(Generator $gen)
{
 $stack = new SplStack;
 // 不断遍历这个传进来的生成器
 for (; ;) {
  // $gen可以理解为指向当前运行的协程闭包函数（生成器）
  $value = $gen->current(); // 获取中断点，也就是yield出来的值
  if ($value instanceof Generator) {
   // 如果是也是一个生成器，这就是子协程了，把当前运行的协程入栈保存
   $stack->push($gen);
   $gen = $value; // 把子协程函数给gen，继续执行，注意接下来就是执行子协程的流程了
   continue;
  }
  // 我们对子协程返回的结果做了封装，下面讲
  $isReturnValue = $value instanceof CoroutineReturnValue; // 子协程返回`$value`需要主协程帮忙处理 
  if (!$gen->valid() || $isReturnValue) {
   if ($stack->isEmpty()) {
    return;
   }
   // 如果是gen已经执行完毕，或者遇到子协程需要返回值给主协程去处理
   $gen = $stack->pop(); //出栈，得到之前入栈保存的主协程
   $gen->send($isReturnValue ? $value->getValue() : NULL); // 调用主协程处理子协程的输出值
   continue;
  }
  $gen->send(yield $gen->key() => $value); // 继续执行子协程
 }
}

class CoroutineReturnValue {
 protected $value;
 
 public function __construct($value) {
  $this->value = $value;
 }
 // 获取能把子协程的输出值给主协程，作为主协程的send参数
 public function getValue() {
  return $this->value;
 }
}
function retval($value) {
 return new CoroutineReturnValue($value);
}

function echoTimes($msg, $max) {
 for ($i = 1; $i <= $max; ++$i) {
  echo "$msg iteration $i\n";
  yield;
 }
 yield retval(""); // 增加这个作为结束标示
}

function task1()
{
 yield echoTimes('bar', 5);
}

 public function __construct($taskId, Generator $coroutine)
 {
  $this->taskId = $taskId;
  $this->coroutine = $coroutine;
  // $this->coroutine = stackedCoroutine($coroutine); //不需要自己实现了，改回之前的
 }

function echoTimes($msg, $max) {
 for ($i = 1; $i <= $max; ++$i) {
  echo "$msg iteration $i\n";
  yield;
 }
}

function task1()
{
 yield from echoTimes('bar', 5);
}

<?php 
ini_set('zend.assertions', 0); 

assert(true == false); 
echo 'Hi!'; 
?>

<?php 
ini_set('zend.assertions', 1); 
ini_set('assert.exception', 1); 

assert(true == false); 
echo 'Hi!'; 
?>

Fatal error: Uncaught AssertionError: assert(true == false) in -:2
Stack trace:
#0 -(2): assert(false, 'assert(true == ...')
#1 {main}
  thrown in - on line 2