## connect, open ##### *Description* Connects to a Redis instance. 连接到一个Redis实例 ##### *Parameters* *host*: string. can be a host, or the path to a unix domain socket host:字符串类型 可以使一个HOST IP或者是一个UNIX DOMAIN SOCKET的路径 *port*: int, optional port:整数型,Redis的运行端口 *timeout*: float, value in seconds (optional, default is 0 meaning unlimited) timeout:浮点型,连接的市场，单位是秒,默认为0即连接没有时间限制 ##### *Return Value* *BOOL*: `<span class="calibre12">TRUE</span>` on success, `<span class="calibre12">FALSE</span>` on error. ##### *Example* ``` <pre class="calibre9">$redis->connect('127.0.0.1', 6379); $redis->connect('127.0.0.1'); // port 6379 by default $redis->connect('127.0.0.1', 6379, 2.5); // 2.5 sec timeout. $redis->connect('/tmp/redis.sock'); // unix domain socket. ```