第一步首先获取安装包，下面以package–RODBC为例子
使用命令install.packages(“RODBC”)
> install.packages("RODBC")
trying URL 'https://cran.rstudio.com/bin/windows/contrib/3.4/RODBC_1.3-15.zip'
Content type 'application/zip' length 831635 bytes (812 KB)
downloaded 812 KB
package ‘RODBC’ successfully unpacked and MD5 sums checked
The downloaded binary packages are in
C:\TMP\RtmpamrjHc\downloaded_packages
使用安装包时，使用命令library(RODBC)将安装包载入就行啦
> library(RODBC)
然后就可以直接使用啦，很简单