lattice xyplot: trouble about the use of yscale.components to start the yscale from zero

On Sun, Jan 22, 2023 at 6:48 PM Laurent Rhelp <LaurentRHelp at free.fr> 
wrote:

    Dear RHelp-list,

    ??I want to choice my scale for every panel in a lattice graph
    according to
    ??the ylim range of every panel, with 10 ticks and with a start
    from 0.
    Also I want to plot a grid
    ?? according to the y ticks (I did that in the panel argument with
    the
    panel.abline function) .
    ??So I decided to use the yscale.components argument and I write the
    script below.
    ??Before using the pretty function I introduce the 0 value in my
    range but
    it does not work : the labels are not displayed and the
    panel.abline do
    nothing. I am not able to understand why.
    ?? If I comment the line ylim <- c(0,max(lim)) the labels appear
    but of
    course they do not start from 0.


You have mistyped

? ans$left$ticks$at <- tick.at <http://tick.at>

as

? ans$left$tick$at <- tick.at <http://tick.at>

You might think that partial matching will help you, but partial 
matching doesn't work for assignment (for obvious reasons). Consider

foo <- list(ticks = list(at = 1:10))
foo$tick$at <- "bar"
str(foo)

List of 2
?$ ticks:List of 1
? ..$ at: int [1:10] 1 2 3 4 5 6 7 8 9 10
?$ tick :List of 1
? ..$ at: chr "bar"

I don't know if there is a good argument for this assignment to work 
at all (other than that NULL and an empty list are conceptually 
equivalent), but it is what it is.

This is why I tend to set options(warnPartialMatchDollar = TRUE). In 
this case it would give you an inaccurate warning, but at least it 
will give you a warning.

As for the range of the scales, these are determined by 'ylim' and 
'prepanel', so you would need to specify one of these.

As you are using scales$axs = "i", you can simply provide ylim = c(0, 
NA), which forces the lower limit to 0, and lets the upper limit be 
decided as usual.

For finer control, you can specify a prepanel function, e.g.,

prepanel = function(x, y, ...) list(ylim = c(0, max(y)))

Hope this helps,

Best,
-Deepayan


    Thank you for your help.

    Laurent


    ??--------------------------o<----------------------------------------------->o-----------------------------------------
    library(lattice)
    library(zoo)
    ##
    ## Rq : mydata is a zoo object
    ##
    mydata <- structure(c(0.190991684047867, 0.186639474048368,
    0.188562286982088,
    ???????????? 0.187781290093149, 0.188242724296645, 0.190412570465429,
    0.188922969182772,
    ???????????? 0.194037520889193, 0.191973884842229, 0.197032138922638,
    1.03204611806177,
    ???????????? 1.02831610106898, 1.0280323738983, 1.03595907392095,
    1.03316162925952,
    ???????????? 1.04755124287765, 1.04403986225312, 1.05686325668364,
    1.04672225664295,
    ???????????? 1.05462971668107), dim = c(10L, 2L), dimnames =
    list(c("f1",
    ????????? "f1", "f1", "f1", "f1", "f1", "f1", "f1", "f1", "f1"),
    c("col1","col2"))
    ????????? , index = c(1.27904891967773, 1.27909898757935,
    1.27915000915527
    ?????? , 1.27920007705688, 1.2792489528656, 1.27929902076721,
    1.27935004234314
    ?????? ,1.27939891815186, 1.27944993972778, 1.27950000762939),
    class =
    "zoo")

    options(digits=17)

    yscale.components.n.ticks <- function(lim,...){

    ?? ans <- yscale.components.default(lim = lim,...)
    ?? ylim <- lim
    ?? ## I want to start from 0
    ?? ylim <- c(0,max(lim))
    tick.at <http://tick.at> <- pretty(ylim, n=10, min.n = 9)
    ??? cat("lim yscale : ",ylim,"\n")

    ?? mylabels_y <- formatC( tick.at <http://tick.at>
    ????????????????????????? , format = "f"
    ????????????????????????? , digits=3
    ????????????????????????? , width=9
    ????????????????????????? ,flag=" ")

    ?? print(cbind( mylabels_y = mylabels_y, tick.at_y = tick.at
    <http://tick.at>))

    ?? ans$left$tick$at <- tick.at <http://tick.at>
    ?? ans$left$labels$at <- tick.at <http://tick.at>
    ?? ans$left$labels$labels <- mylabels_y
    ?? ans
    }


    xscale.components.n.ticks <- function(lim, ... ){

    ?? ans <- xscale.components.default(lim = lim,...)
    tick.at <http://tick.at> <- pretty(lim,20,9)
    ?? mylabels_x <- formatC( tick.at <http://tick.at>
    ????????????????????????? , format = "f"
    ????????????????????????? , digits=6
    ????????????????????????? , width=9
    ????????????????????????? , flag=" ")

    ?? print(cbind( mylabels_x = mylabels_x, tick.at_x = tick.at
    <http://tick.at>))

    ?? ans$bottom$tick$at <- tick.at <http://tick.at>
    ?? ans$bottom$labels$at <- tick.at <http://tick.at>
    ?? ans$bottom$labels$labels <- mylabels_x
    ?? ans
    }

    # to see the x values
    time(mydata)

    gr <- xyplot(? mydata
    ??????????????? , main = "title"
    ??????????????? , layout = c(1,2)
    ??????????????? , pch = 20
    ??????????????? , panel = function(...) {

    ????????????????? ylim <- current.panel.limits()$ylim
    ????????????????? xlim <- current.panel.limits()$xlim

    ????????????????? ## I create here the same ticks that those created
    ????????????????? ##? in xscale.components and yscale.components
    ????? ???????? ? ylim <- c(0,max(ylim))
    ???????????????? cat("ylim panel : ",ylim,"\n")
    y.tick.at <http://y.tick.at> <- pretty(ylim,10,9)
    ???????????????? print(cbind(y.tick.at.panel= y.tick.at
    <http://y.tick.at>))

    x.tick.at <http://x.tick.at> <- pretty(xlim,20,9)

    ???????????????? panel.abline( h = y.tick.at <http://y.tick.at>, v
    = x.tick.at <http://x.tick.at>, col =
    "lightgrey")

    ????????????????? panel.xyplot(...)
    ??????????????? }
    ##?????????????? , ylim = c(0,1.5)
    ??????????????? , scales = list(
    ????????????????? y= list(?? relation = "free"
    ?????????????????????????? , axs="i"
    ?????????????????????????? , rot = 45
    ?????????????????????????? ),
    ????????????????? x = list(
    ????????????????????????????? axs="i"
    ??????????????????????????? , rot = 90
    ?????????????????????????? )
    ??????????????? )
    ??????????????? , yscale.components = yscale.components.n.ticks
    ??????????????? , xscale.components = xscale.components.n.ticks

    )

    print(gr)

    -- 
    Cet e-mail a ?t? v?rifi? par le logiciel antivirus d'Avast.
    www.avast.com <http://www.avast.com>