[Rd] ylab in time series plot (PR#2869)

[Ed Kademan]

Prof Brian Ripley <ripley at stats.ox.ac.uk> writes:

> On 29 Apr 2003, Ed Kademan wrote:
> 
> > Prof Brian Ripley <ripley at stats.ox.ac.uk> writes:
> > 
> > > And the bug is?
> > > 
> > > You got a correct plot, with a correct warning.
> > > 
> > > On Mon, 28 Apr 2003 kademan at phz.com wrote:
> > > 
> > > > You get a warning message when you specify a ylab parameter while
> > > > plotting data whose x's are POSIXct values.  Apparently the
> > > > `axis.POSIXct' method tries to reset the ylab---via the ...
> > > > parameter---after it has already been set by higher level methods.
> > 
> > No.  The bug is that the warning is incorrect.
> > 
> > How do you specify a ylab parameter to a time series plot without
> > generating a warning?
> 
> [This is not a time-series plot!  You are plotting against a date-time 
> object, and this has nothing to do with a time series: the object does not 
> even have to be in data order.]
> 
> You are not able to, but nowhere is it stated that you can -- so it is not 
> a bug.

When I look up the manual page for `axis.POSIXct' I get the following:

  Functions to plot objects of classes "POSIXlt" and "POSIXct"
  representing calendar dates and times.

  Usage

  plot(x, y, xlab = "", ...)
  axis.POSIXct(side, x, at, format, ...)

  Arguments

   x, at
          A date-time object.
   y
          numeric values to be plotted against x.
   xlab
          a character string giving the label for the x axis.
   side
          See axis.
   format
          See strptime.
   ...rther arguments to be passed from or to other methods, typically graphical parameters.