On 12/31/2005 8:57 AM, Gabor Grothendieck wrote: > It could be changed to missing(y) || is.null(y) and the docs amended. > That way existing code will continue to work and code that otherwise > gives an error currently, but should have worked, will now work too.
Can you give an example where you would want to use xy.coords(y ~ x)? Normally xy.coords() is used in other functions, and they can default y to NULL (see plot.default, for example). Duncan Murdoch > > On 12/31/05, Duncan Murdoch <[EMAIL PROTECTED]> wrote: > >>On 12/30/2005 10:10 PM, Gabor Grothendieck wrote: >> >>>In ?xy.coords it says: >>> >>> If 'y' is missing and 'x' is a >>> >>> formula: of the form 'yvar ~ xvar'. 'xvar' and 'yvar' are used as >>> x and y variables. >>> >>> list: containing components 'x' and 'y', these are used to define >>> plotting coordinates. >>> >>> time series: the x values are taken to be 'time(x)' and the y >>> values to be the time series. >>> >>> matrix with two columns: the first is assumed to contain the x >>> values and the second the y values. >>> >>>however, in fact, if y is missing an error is given. e.g. >>> >>>x <- 1:3 >>>y <- 4:6 >>>xy.coords(y ~ x) # error >>>xy.coords(cbind(x, y)) # error >>>xy.coords(ts(y)) # error >>> >>>Looking at the code, is.null(y) in the first line of the >>>body should be missing(y) . >> >>It would be better to change the docs to say "if 'y' is NULL ...". The >>code has been the way it is for years and years, and is widely used. >> >>Changing the test to missing(y) would mean all existing uses that put a >>NULL there would need to be changed. >> >>Adding a default value of NULL to y would have less impact, but I'd >>still be worried about it having long-range bad effects. >> >>Duncan Murdoch >> ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
