用RStudio无法加载程序包，不论安装什么包都会报错
Warning in install.packages : downloaded length 274432 != reported length 283427Warning in install.packages : error 1 in extracting from zip fileWarning in install.packages : cannot open compressed file 'lmtest/DESCRIPTION', probable reason 'No such file or directory'Error in install.packages : cannot open the connection
但是在R里面却没有问题，并且R里面加载成功后，RStudio也可以直接使用
Warning in install.packages : downloaded length 274432 != reported length 283427Warning in install.packages : error 1 in extracting from zip fileWarning in install.packages : cannot open compressed file 'lmtest/DESCRIPTION', probable reason 'No such file or directory'Error in install.packages : cannot open the connection
但是在R里面却没有问题，并且R里面加载成功后，RStudio也可以直接使用
