第五课字符串 · 万能Web开发文档笔记

# 第五课字符串 > 字符长度 ``` <pre class="calibre14">``` strlen($str) 中文utf8中3个长度其他字符1个,gb2312中中文2个 mb_strlen($str1,'utf-8'); ``` ``` > 截取,字符串截取,用于英文,长度每个汉字utf8占3字符 ``` <pre class="calibre14">``` substr($str1,0,6); 开始位置0,长度 mb_substr('曾经年少爱追梦一心只想往前飞', 0, 7,'utf-8'); ``` ``` > 查找替换,查找c替换成qqq ``` <pre class="calibre14">``` str_replace('c','qqq','abcdefg'); ``` ``` > header ``` <pre class="calibre14">``` header("Content-Type:text/html;charset=UTF-8"); header('Content-type: text/css'); css header('Content-type: text/javascript'); js header('Content-type: image/jpeg'); jpg header('Content-type: application/json'); json header('Content-type: text/plain'); txt header('Content-type: text/xml'); xml header('HTTP/1.1 200 OK'); 200 正常ok header("HTTP/1.1 404 Not Found");未找到 header("http/1.1 403 Forbidden");无权限 header("http/1.1 301 Moved Permanently");重定向 header('HTTP/1.1 304 Not Modified');没改变 header('Location: http://www.example.org/'); header('Refresh: 10; url=http://www.example.org/'); header('Content-Disposition: attachment; filename="downloaded.pdf"'); 跨域 header('Access-Control-Allow-Origin: *'); header('Access-Control-Allow-Headers:content-type'); header('Content-Type:application/json; charset=utf-8'); ``` ``` > serialize 和unserialize 序列化和反序列化 > json\_encode($arr)和json\_decode($json,TRUE)true是返回数组默认对象 json\_encode($arr,JSON\_UNESCAPED\_UNICODE ) 编码后还是中文 > urlencode 和urldecode url编码和解码 ``` <pre class="calibre14">``` mb_convert_encoding('李太白',"utf-8",'auto');自动转换成uft8 iconv('utf-8','gb2312//IGNORE','礼拜是谁');转换成gb2312 ``` ``` > strtolower转换小写 strtoupper转换成大写 ``` <pre class="calibre14">``` strtolower('wEws2'); ``` ``` > strip\_tags($rs0); 去除标签 > error\_reporting(0);禁止显示错误 > error\_reporting(E\_ALL)显示错误 ``` <pre class="calibre14">``` pathinfo(__FILE__) Array ( [dirname] => C:\www [basename] => Codelobster1.php [extension] => php [filename] => Codelobster1 ) ``` ``` 添加和去除转义符 ``` <pre class="calibre14">``` addslashes("wo \' \"ni是"); 入库添加反斜杠 stripslashes("wo \' \"ni是"); ``` ``` > 转换实体和还原 ``` <pre class="calibre14">``` htmlspecialchars_decode($str) htmlspecialchars("你是",ENT_NOQUOTES,'UTF-8'); ``` ``` > 检测扩展是否存在,curl,gd,openssl ``` <pre class="calibre14">``` extension_loaded('memcache'); function_exists('curl_init');//检测函数是否存在 class_exists('MyClass')) 检测类是否存在 get_extension_funcs("xml"); 显示所有方法 get_loaded_extensions() 显示所有扩展 get_defined_constants(true)['user']一已定义常量 $arr = get_defined_functions();$arr['user'] 已定义函数 ``` ``` > 如果自动添加转义符没有打开则使用以下 ``` <pre class="calibre14">``` if(!get_magic_quotes_gpc()){ addslashes($var) } ``` ``` > 解析url ``` <pre class="calibre14">``` parse_url("http://www.baidu.com/4/1.php?qq=1&d=1#123"); Array ( [scheme] => http [host] => www.baidu.com [path] => /4/1.php [query] => qq=1&d=1 [fragment] => 123 ) ``` ``` > 解析字符串 ``` <pre class="calibre14">``` parse_str("id=23&name=John%20Adams",$arr);输出$arr Array ( [id] => 23 [name] => John Adams ) ``` ``` 变量数组互换 ``` <pre class="calibre14">``` $arr = array('qq'=>1,'ss'=>5); extract($arr);//转换成变量 $a=1;$b=2; $arr = compact('a','b'); ``` ``` > 获取输入,post可用 ``` <pre class="calibre14">``` $str=file_get_contents('php://input'); 等同$_POST,用于 ``` ``` > $\_SERVER ``` <pre class="calibre14">``` OS系统 [HTTP_HOST] => localhost 域名 [HTTP_USER_AGENT] => Mozilla/5.0 (Windows NT 6.2; WOW64; Trident/7.0; rv:11.0) like Gecko [SERVER_SOFTWARE] => nginx/1.9.9 [REQUEST_METHOD] => GET [SCRIPT_FILENAME] => C:/www/Codelobster1.php [SERVER_ADDR] => 127.0.0.1 [REMOTE_ADDR] => 127.0.0.1 [REQUEST_URI] => /Codelobster1.php?qq=1 ``` ``` > 生成id ``` <pre class="calibre14">``` uniqid() 默认13 uniqid('y_',1); 25 没有 y_则是23 ``` ``` > 字符串反序 > `strrev("abc")` 去除html标签 `strip_tags($str)`