[R] plot.POSIXct plot.POSIXlt

[Patrick Giraudoux]

Hi,

Just to signal that when I want to plot POSIXct variable on x using 
format within plot(), I get what I want on the plot but with a number of 
warnings:

 > plot(y~x,format="%y-%m")
Warning messages:
1: "format" is not a graphical parameter in: plot.window(xlim, ylim, 
log, asp, ...)
2: "format" is not a graphical parameter in: plot.xy(xy, type, pch, lty, 
col, bg, cex, lwd, ...)
3: "format" is not a graphical parameter in: axis(side, at, labels, 
tick, line, pos, outer, font, lty, lwd, 
4: "format" is not a graphical parameter in: box(which = which, lty = 
lty, ...)
5: "format" is not a graphical parameter in: title(main, sub, xlab, 
ylab, line, outer, ...)

I suppose that format may not be at the right place in plot() or/and not 
handled by the functions called from there, however the documentation 
(?plot.POSIXct) seems to allow passing this argument:

 ...: Further arguments to be passed from or to other methods,
          typically graphical parameters or arguments of
          'plot.default'.  For the 'plot' methods, also 'format'.

Any comment?

Patrick