[R] lattice: option to sort x when type = l

[Felix Andrews]

try type = "a"

-Felix


On 27 July 2010 14:11, Prasenjit Kapat <kapatp at gmail.com> wrote:
> Hi,
>
> (please Cc me)
>
> In xyplot (), type = "l" (or one that includes "l", *el*) is
> (generally) meaningful only when the 'x' variable is sorted. In
> practice, one either sorts the data frame before hand or writes a tiny
> panel function which sorts the supplied x and then calls the default
> panel.xyplot(). Trouble arises when there is a conditional variable as
> well as a groups argument.
>
> Of course, sorting the data frame before hand is the simplest
> solution. But, when one wishes to plot against multiple 'x' variables
> the data has to be sorted each time, which, to me, doesn't seem the
> "right" way (of course, a personal opinion). Hence a feature request
> to add a sort option when type = "l".
>
> Before giving a reproducible example, is there anything even simpler
> that I have missed?
>
> Example:
>
> Everything included:
>
>> source ('http://www.stat.osu.edu/~pkapat/miscl/Code4xyplot_sort_type_l.R')
>
> OR, step by step:
>
>> library (lattice)
>>
>> # toy data
>> D <- read.csv ('http://www.stat.osu.edu/~pkapat/miscl/Data4xyplot_sort_type_l.csv')
>>
>> # default behavior: obviously wrong
>> xyp1 <- xyplot (y ~ x/1000 | C, groups = G, data = D, type = "o", main = 'Wrong behavior, obviously')
>>
>> # simplest soln:
>> xyp2 <- xyplot (y ~ x/1000 | C, groups = G, data = with (D, D[do.call (order, list (x, C, G)),]), type = "o", main = 'Using pre-sorted data frame')
>>
>> # hack:
>> # adds an additional `if' inside the `if ("l" %in% type) {...}' block of the default panel.xyplot ()
>> # which reads default.args$sort.type.l (this should be set to FALSE, by default)
>> source ('http://www.stat.osu.edu/~pkapat/miscl/panel.xyplot.sort.R')
>>
>> lattice.options (default.args = list (sort.type.l = TRUE))
>> xyp3 <- update (xyp1, main  = 'Using hacked panel.xyplot', panel = function (...) panel.xyplot (...)) # using the hacked panel.xyplot ()
>>
>> # display:
>> plot (xyp1); dev.new (); plot (xyp2); dev.new (); plot (xyp3)
>
> Regards,
> --
> Prasenjit
>
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>



-- 
Felix Andrews / 安福立
http://www.neurofractal.org/felix/