错误代码=无效的因子水平，即使添加“ stringsAsFactors = FALSE”，也不会生成NA

Question

运行此代码时，我收到以下错误消息：

  

无效的因子水平，NA生成

有人知道是什么导致了下面的代码吗？

CurrentMonth<- base1[3,"Calendar month"]
RowEastCoast<- Querry1[1, "YD3"]

CurrentEastCoastForecast = data.frame(Month= CurrentMonth, Year= CurrentYear, FLEastCoast = RowEastCoast , stringsAsFactors = FALSE  )

NEWFLEastCoast<-rbind(OldFLEastCoast, CurrentEastCoastForecast ) 
View(CurrentEastCoastForecast)