# Redis 入门到精通（二）通用指令

## 一、redis 通用指令-key 基本操作

### 1、key 特征

最近redis差不多看完了，前面学的也忘了好多，所以正好写篇博客复习复习。此篇介绍的是redis的基础篇，希望这篇能帮到各位大佬。

redis数据类型及应用场景

Redis支持5种数据类型：string（字符串），hash（哈希），list（列表），set（集合）及zset(sorted set：有序集合)。

1、string

简介：Strings数据类型是最常用、简单的key-value类型，普通的key/ value 存储都可以归为此类。value不仅可以是字符串，也可以是数字。因为是二进制安全的，所以你完全可以把一个图片文件的内容作为string来存储。Redis的string可以完全实现目前memcached的功能，并且效率更高。除了提供与 Memcached 一样的get、set、incr、decr 等操作外，Redis还额外提供了下面一些操作：

作者：民工哥

链接：https://segmentfault.com/a/1190000022353594

1、Redis简介

It’s not surprising that the Main-Board Market, aka the benchmark Shanghai Composite Index, the Shenzhen Component Index and the Growth Enterprises Market, namely the tech-heavy ChiNext Index opened lower and closed higher due to the face that the stocks in the Beijing Stock Exchange took a nosedive in late trading in various adverse conditions. After all, the seesaw effect should have taken shape given that the stocks in the Beijing Stock Exchange will plummet in succession if other markets rise in today’s polarized environment. There is little doubt that the ill-fated hard-pressed innocent retail investors are excited that a slight bear market rally came in time in the already berserk domestic equity markets at a delicate moment. Today it’s very palpable that the stronger-than-expected market performance and weaker-than-expected market correction should have showcased more signs of upward trend in the Beijing Stock Exchange in the brutal market environment. The ill-fated hard-pressed innocent retail investors seem to have realized that the words from the top level were a great encouragement to domestic capital over the past few weeks. That should have reinforced a view that the top level seems to acquiesce in speculation given that propping up market run in the Beijing Stock Exchange is intended to stave off the redemption funds before they expire. There is ample evidence suggesting that the current robust rebound in the Beijing Stock Exchange should have given the retail investors’ confidence about the upward trend for the remainder of the year. To be sure, the already gradual level-headed veteran retail investors haven’t ruled out other regulative measures in the short term because the previous red-hot stocks halted today. To be honest, the biggest concern is that a spate of uncertainties will beget a drastic market correction in the environment of a renewable vigorous market selloff. Nowadays, the retail investors not only believe, but know a fact that the upside is far from over in the Being Stock Exchange when other markets underperform under the weight of market correction. Consequently, it’s hard not to draw the conclusion that the stocks in the Beijing Stock Exchange will pare back their losses as soon as tomorrow or as late as Friday. Generally speaking, some retail investors still remain confident that they should have geared up for a strong return to the stocks in the Beijing Stock Exchange tomorrow. In addition, the savvy control risk pundits, the ever-optimistic market observers and already gradual level-headed veteran retail investors wouldn’t be surprised if the benchmark Shanghai Composite Index suddenly fall below 3,000-point mark at some point next month because of an extreme aversion to risk.