I am trying to plot data within a specific date range for individuals. I've pasted example code below that has worked before, but I don't wall all the data, just what happens after 11/30/2016. I've tried the solution shown here ([Select Data After Specific Date](https://stackoverflow.com/questions/22554166/select-data-after-specific-date)), but I get "Error: Invalid input: date\_trans works with objects of class Date only." Any ideas? 

```
 mydf<- data.frame(Date = as.Date(Subject$date, format = "%m/%d/%Y"),
                   variable1 = (Subject$var1),
                   variable2 = (Subject$var2), 
                   variable3 = (Subject$var3),
                   variable4 = (Subject$var4))

ggplot(mydf, aes(Date > "2016-11-30", variable1)) + 
  geom_point() + 
  stat_smooth(color = "blue", fill = "lightskyblue") +
  theme(axis.title.x = element_blank()) + 
  ylab("") + xlab("")+ 
  ggtitle("Variable 1 units") + 
  scale_x_date(date_breaks = "months", 
               date_labels = "%b%y") + 
  theme_hc()

```