Heim > Backend-Entwicklung > PHP-Tutorial > PHP_基础,php基础_PHP教程

PHP_基础,php基础_PHP教程

WBOY
Freigeben: 2016-07-12 09:00:30
Original
982 Leute haben es durchsucht

PHP_基础,php基础

目录

  • 数组

  • 函数

  • 类和对象

  • 字符串操作

  • 会话控制

  • 时间和日期

  • 异常处理

 

一、数组

  1、索引数组

<span>header</span>("Content-Type: text/html; charset=utf-8"<span>);

</span><span>//</span><span>创建空数组</span>
<span>$str</span> = <span>array</span><span>();

</span><span>//</span><span>索引数组:数组的键是整数的数组,并且键的整数顺序是从0开始,依次类推。</span>
<span>$fruit</span> = <span>array</span>("苹果","香蕉","菠萝"<span>);

</span><span>//</span><span>索引数组赋值:
//1.用数组变量的名字后面跟一个中括号的方式赋值</span>
<span>$arr</span>[0]='苹果'<span>;
</span><span>//</span><span>使用=>符号来分隔键和值,左侧表示键,右侧表示值。</span>
<span>array</span>('0'=>'苹果'<span>);

</span><span>//</span><span>count($arr)返回数组长度

//for循环访问索引数组里的值</span>
<span>for</span>(<span>$i</span>=0; <span>$i</span><<span>count</span>(<span>$fruit</span>); <span>$i</span>++<span>){
    </span><span>echo</span> "<span>$fruit</span>[<span>$i</span>]<br>"<span>;
}

</span><span>//</span><span>foreach循环访问索引数组里的值</span>
<span>foreach</span>(<span>$fruit</span> <span>as</span> <span>$k</span>=><span>$v</span><span>){
    </span><span>echo</span> <span>$k</span>."...".<span>$v</span>."<br>"<span>;
}</span>
Nach dem Login kopieren

  2、关联数组

<span>header</span>("Content-Type: text/html; charset=utf-8"<span>);

</span><span>//</span><span>关联数组:指数组的键是字符串的数组</span>
<span>$fruit</span> = <span>array</span>('apple'=>"苹果", 'banana'=>"香蕉", 'pineapple'=>"菠萝"<span>);

</span><span>//</span><span>关联数组赋值
//1.用数组变量的名字后面跟一个中括号的方式赋值</span>
<span>$arr</span>['apple']='苹果'<span>;
</span><span>//</span><span>2.使用=>符号来分隔键和值,左侧表示键,右侧表示值</span>
<span>array</span>('apple'=>'苹果'<span>);

</span><span>//</span><span>foreach循环访问关联数组里的值</span>
<span>foreach</span>(<span>$fruit</span> <span>as</span> <span>$k</span>=><span>$v</span><span>){
    </span><span>echo</span> '<br>水果的英文键名:'.<span>$k</span>.',对应的值是:'.<span>$v</span><span>;
}</span>
Nach dem Login kopieren

二、函数

  1.可变函数

<span>//</span><span>可变函数,通过变量的值来调用函数</span>
<span>function</span><span> name() {
    </span><span>echo</span> 'jobs'<span>;
}
</span><span>$func</span> = 'name'<span>;
</span><span>//</span><span>调用可变函数</span>
<span>$func</span>(); 
Nach dem Login kopieren

  2.判断函数是否存在

<span>function</span><span> func() {
}
</span><span>if</span> (<span>function_exists</span>('func'<span>)){
    </span><span>echo</span> 'exists'<span>;
}</span>
Nach dem Login kopieren

三、类和对象 

<span>//</span><span>定义一个类</span>
<span>class</span><span> Car {
    </span><span>//</span><span>定义属性</span>
    <span>public</span> <span>$name</span> = '汽车'<span>;
    </span><span>//</span><span>定义方法</span>
    <span>public</span> <span>function</span><span> getName() {
        </span><span>//</span><span>方法内部可以使用$this伪变量调用对象的属性或者方法</span>
        <span>return</span> <span>$this</span>-><span>name;
    }
}
</span><span>//</span><span>实例化一个对象</span>
<span>$car</span> = <span>new</span><span> Car();
</span><span>//</span><span>调用对象的方法</span>
<span>echo</span> <span>$car</span>-><span>getName();

</span><span>//</span><span>类的属性
//public:公开的
//protected:受保护的,受保护的属性不允许外部调用
//private:私有的,私有属性不允许外部调用

//静态方法:使用关键字static修饰
//静态方法不需要实例化对象,可以通过类名直接调用,操作符为双冒号::</span>
<span>class</span><span> Car {
    </span><span>public</span> <span>static</span> <span>function</span><span> getName() {
        </span><span>return</span> '汽车'<span>;
    }
​}
</span><span>echo</span> Car::getName(); <span>//</span><span>结果为&ldquo;汽车&rdquo;

//构造函数__construct():在每次对象创建的时候调用该函数
//析构函数__destruct():在每次对象销毁的时候调用该函数</span>
<span>class</span><span> Car {
    </span><span>//</span><span>增加构造函数与析构函数</span>
    <span>function</span><span> __construct() {
        </span><span>print</span> "构造函数被调用 \n"<span>;
    }
    </span><span>function</span><span> __destruct() {
        </span><span>print</span> "析构函数被调用 \n"<span>;
    }
}
</span><span>$car</span> = <span>new</span> Car();
Nach dem Login kopieren

四、字符串操作

  1.单双引号的区别

<span>//</span><span>双引号串中直接包含字串变量
//单引号串中的内容总被认为是普通字符</span>
<span>$str</span>='hello'<span>;
</span><span>echo</span> "str is <span>$str</span>"; <span>//</span><span>运行结果: str is hello</span>
<span>echo</span> 'str is $str'; <span>//</span><span>运行结果: str is $str</span>
Nach dem Login kopieren

  2.去除字符串首尾的空格

<span>//</span><span>trim去除一个字符串两端空格。
//rtrim是去除一个字符串右部空格
//ltrim是去除一个字符串左部空格</span>
<span>trim</span>(" 空格 ");
Nach dem Login kopieren

  3.获取字符串的长度

<span>//</span><span>英文字符长度</span>
<span>strlen</span>(<span>$str</span><span>);
</span><span>//</span><span>中文字符长度</span>
mb_strlen(<span>$str</span>,"UTF8");
Nach dem Login kopieren

  4.字符串的截取

<span>//</span><span>英文字符串的截取函数substr()
//substr(字符串变量,开始截取的位置,截取个数)</span>
<span>$str</span>='i love you'<span>;
</span><span>echo</span> <span>substr</span>(<span>$str</span>, 2, 4<span>);

</span><span>//</span><span>中文字符串的截取函数mb_substr()
//mb_substr(字符串变量,开始截取的位置,截取个数, 网页编码)</span>
<span>$str</span>='我爱你,中国'<span>;
</span><span>echo</span> mb_substr(<span>$str</span>, 4, 2, 'utf8');
Nach dem Login kopieren

  5.字符串查找

<span>//</span><span>strpos(要处理的字符串, 要定位的字符串, 定位的起始位置[可选])</span>
<span>$str</span> = 'I want to study at imooc'<span>;
</span><span>$pos</span> = <span>strpos</span>(<span>$str</span>, 'imooc');
Nach dem Login kopieren

  6.字符串替换

<span>//</span><span>str_replace(要查找的字符串, 要替换的字符串, 被搜索的字符串, 替换进行计数[可选])</span>
<span>$str</span> = 'I want to learn js'<span>;
</span><span>$replace</span> = <span>str_replace</span>('js', 'php', <span>$str</span>);
Nach dem Login kopieren

  7.字符串的合并与分割

<span>//</span><span>字符串合并函数implode():把数组元素组合为一个字符串
//implode(分隔符[可选], 数组)</span>
<span>$arr</span> = <span>array</span>('Hello', 'World!'<span>);
</span><span>$result</span> = <span>implode</span>('', <span>$arr</span><span>);
</span><span>print_r</span>(<span>$result</span>);<span>//</span><span>结果显示Hello World!

//字符串分隔函数explode():函数返回由字符串组成的数组
//explode(分隔符[可选], 字符串)</span>
<span>$str</span> = 'apple,banana'<span>;
</span><span>$result</span> = <span>explode</span>(',', <span>$str</span><span>);
</span><span>print_r</span>(<span>$result</span>);<span>//</span><span>结果显示array('apple','banana')</span>
Nach dem Login kopieren

五、会话控制

  1.cookie  

<span>//</span><span>设置cookie
//name( Cookie名)可以通过$_COOKIE['name'] 进行访问
//value(Cookie的值)
//expire(过期时间)Unix时间戳格式,默认为0,表示浏览器关闭即失效
//path(有效路径)如果路径设置为'/',则整个网站都有效
//domain(有效域)默认整个域名都有效,如果设置了'www.imooc.com',则只在www子域中有效</span>
<span>$value</span> = 'test'<span>;
</span><span>setcookie</span>("TestCookie", <span>$value</span><span>);
</span><span>//</span><span>有效期一小时</span>
<span>setcookie</span>("TestCookie", <span>$value</span>, <span>time</span>()+3600<span>);

</span><span>//</span><span> cookie的删除与过期时间</span>
<span>setcookie</span>('test', '', <span>time</span>()-1);
Nach dem Login kopieren

  2.session

<span>//</span><span>先执行session_start方法开启session</span>
<span>session_start</span><span>();

</span><span>//</span><span>通过全局变量$_SESSION进行session的读写。</span>
<span>$_SESSION</span>['name'] = 'jobs'<span>;
</span><span>echo</span> <span>$_SESSION</span>['name'<span>];

</span><span>//</span><span>删除某个session</span>
<span>unset</span>(<span>$_SESSION</span>['name'<span>]);
</span><span>//</span><span>删除所有session</span>
<span>session_destroy</span>();
Nach dem Login kopieren

六、时间和日期

<span>//</span><span>UNIX 时间戳:表示从 1970年1月1日 00:00:00 到当前时间的秒数之和。
//函数 time() 来取得服务器当前时间的时间戳</span>
<span>$time</span>=<span>time</span><span>();
</span><span>echo</span> <span>$time</span><span>;

</span><span>//</span><span>date()函数,来取得当前的日期
//date(时间戳的格式, 规定时间戳【默认是当前的日期和时间,可选】)
//设置默认的时区</span>
date_default_timezone_set('Asia/Shanghai'<span>);
</span><span>//</span><span>输出1396193923对应的日期</span>
<span>echo</span> <span>date</span>("Y-m-d"<span>);

</span><span>//</span><span>函数strtotime实现功能:获取某个日期的时间戳,或获取某个时间的时间戳
//strtotime(要解析的时间字符串, 计算返回值的时间戳【默认是当前的时间,可选】)
//1398700800,这个数字表示从1970年1月1日 00:00:00 到2014年4月29号经历了1398700800秒</span>
<span>echo</span> <span>strtotime</span>('2014-04-29'<span>);
</span><span>//</span><span>1398700801,这个数字表示从1970年1月1日 00:00:00 到2014-04-29 00:00:01时经历了1398700801秒</span>
<span>echo</span> <span>strtotime</span>('2014-04-29 00:00:01');
Nach dem Login kopieren

七、异常处理

<span>//</span><span>创建可抛出一个异常的函数</span>
<span>function</span> checkNum(<span>$number</span><span>){
    </span><span>if</span>(<span>$number</span>>1<span>){
        </span><span>throw</span> <span>new</span> <span>Exception</span>("异常提示-数字必须小于等于1"<span>);
    }
    </span><span>return</span> <span>true</span><span>;
}

</span><span>//</span><span>在 "try" 代码块中触发异常</span>
<span>try</span><span>{
    checkNum(</span>2<span>);
    </span><span>//</span><span>如果异常被抛出,那么下面一行代码将不会被输出</span>
    <span>echo</span> '如果能看到这个提示,说明你的数字小于等于1'<span>;
}</span><span>catch</span>(<span>Exception</span> <span>$e</span><span>){
    </span><span>//</span><span>捕获异常</span>
    <span>echo</span> '捕获异常: ' .<span>$e</span>-><span>getMessage();
}

</span><span>//</span><span>Exception具有几个基本属性与方法,其中包括了:

//message 异常消息内容
//code 异常代码
//file 抛出异常的文件名
//line 抛出异常在该文件的行数

//其中常用的方法有:
//getTrace 获取异常追踪信息
//getTraceAsString 获取异常追踪信息的字符串
//getMessage 获取出错信息</span>

<span>class</span> MyException <span>extends</span> <span>Exception</span><span> {
    </span><span>function</span><span> getInfo() {
        </span><span>return</span> '自定义错误信息'<span>;
    }
}

</span><span>try</span><span> {
    </span><span>throw</span> <span>new</span> MyException('error'<span>);
} </span><span>catch</span>(<span>Exception</span> <span>$e</span><span>) {
    </span><span>echo</span> <span>$e</span>-><span>getInfo();
}</span>
Nach dem Login kopieren

 

www.bkjia.comtruehttp://www.bkjia.com/PHPjc/1093106.htmlTechArticlePHP_基础,php基础 目录 数组 函数 类和对象 字符串操作 会话控制 时间和日期 异常处理 一、数组 1、索引数组 header ("Content-Type: text/html; c...
Verwandte Etiketten:
php
Quelle:php.cn
Erklärung dieser Website
Der Inhalt dieses Artikels wird freiwillig von Internetnutzern beigesteuert und das Urheberrecht liegt beim ursprünglichen Autor. Diese Website übernimmt keine entsprechende rechtliche Verantwortung. Wenn Sie Inhalte finden, bei denen der Verdacht eines Plagiats oder einer Rechtsverletzung besteht, wenden Sie sich bitte an admin@php.cn
Beliebte Tutorials
Mehr>
Neueste Downloads
Mehr>
Web-Effekte
Quellcode der Website
Website-Materialien
Frontend-Vorlage