尝试加载ggplot2时出现以下错误。我尝试卸载scales并重新安装它但由于某些原因，当我想删除软件包时，R无法找到该软件包...
Error in loadNamespace(i, c(lib.loc, .libPaths()), versionCheck = vI[[i]]) :
namespace ‘scales’ 0.2.5 is already loaded, but >= 0.3.0 is required
In addition: Warning message:
package ‘ggplot2’ was built under R version 3.2.3
Error: package or namespace load failed for ‘ggplot2’