coplot using Date object (PR#8147)

Full_Name: Michael Toews
Version: 2.1.1
OS: WinXP (SP2)
Submission from: (NULL) (142.58.206.114)


This is a simple feature request concerning the display of the axis in the
coplot function.
Consider an arbritrary set of values from 1990-1999:

date <- as.Date(paste(rep(1990:1999,each=365),1:365),"%Y %j")
mon <- factor(months(date,T),levels=month.abb)
value <- runif(3650)

# Now create coplot for each month:
coplot(value ~ date | mon)

# The resulting date on the x-axis is not like the axis produced from:
plot(value ~ date)