[R] plot POSIXct format data

[Jingru Dai]

Hi, everyone

I've been trying to make a scatter plot of POSIXct format data to see 
the difference between two start time.
Like X:
[1] "1995-05-26 19:00:00" "1995-05-27 01:00:00" "1995-05-27 07:00:00"
[4] "1995-06-29 01:00:00" "1995-06-29 07:00:00" "1995-06-30 13:00:00"
[7] "1995-06-30 19:00:00" "1995-07-01 01:00:00" "1995-07-01 07:00:00"
......
Y:
[1] "1995-05-26 19:00:00" "1995-05-27 01:00:00" "1995-05-27 07:00:00"
[4] "1995-06-29 01:00:00" "1995-06-29 07:00:00" "1995-06-30 13:00:00"
[7] "1995-06-30 19:00:00" "1995-07-01 01:00:00" "1995-07-01 07:00:00"
.......

But it seems plot(x,y) doesn't work, y have to be numeric format.  Is 
there any special command for that or I should change the format of the 
data?
Thanks

Jingru Dai
----
School of Mathematical Sciences
Rm 454, Building 28
Monash University, 3800
Victoria, Australia