Working with dates and abline(v) in R

Question

I'm working on a set of scatter plots in R, and I want to add a vertical line to all of them. The x-axis is in Date type, and I think that's the problem for me. When I call

abline(v=movie_revenues$X, col="orange")

the line does not show up on the plot. The column "X" is the movie's premiere date, in this form: "11-Dec-2011". When I try to cast it as a date using as.Date(), it gives me an error saying that the text is in ambiguous form.

From this, I guess there are two points where I could have gone wrong.

1. R doesn't recognize 11-Dec-2011 as a date, but tries to plot it anyway without throwing an error, resulting in a missing vertical line; or,
2. the date is recognized correctly, but I've called abline incorrectly, or abline's plotted the line too thin/small for me to see (the y-axis on these plots are very large).

I'm new to R, so please let me know if there's anything silly I've missed.

Thanks!

Answer 1

The issue was resolved when I used the lubridate package for BOTH my x-axis and my vertical line. For some reason, when I used as.Date() for the x-axis points but lubridate for the vertical line coordinate, the line would not appear.