[R] lattice: how to use a log scale on the x-axis with the bwplot function

[Laurent Rhelp]

Dear R-Help list,

    I would like to use bwplot from the lattice package with a log scale 
both on
the x-axis and the y-axis but I do not know how to do that because I do 
not know
how to change the factor x-axis in a numeric x-axis.

  Here is my example:


library(lattice)

# the mock data
y <- runif(100000,min=0, max=500)
x <- seq(0,500,length=length(y))
# I cut the x variable to create a factor variable in order to calculate 
the boxes
groups <- cut(x,10,ordered_result = TRUE)
# creating the dataframe for the lattice functions
DF <- data.frame( x= x , y = y, groups = groups)


## ok for xyplot
xyplot(   y ~ x
           , data=DF
           , scales = list(
             y = list(log=T)
             , x = list(log=T)

           )
)

## ok for bwplot with the log scale for the y-axis
bwplot( y ~ groups
           , data=DF
           , scales = list(
             y = list(log=T)
             #     , x = list(log=T)

           )
)



## Non ok for bwplot with the log scale for the x-axis
bwplot( y ~ groups
         , data=DF
         , scales = list(
               y = list(log=T)
             , x = list(log=T)

         )
)
which gives an error because the x-axis is a factor, I would like to 
replace it
for the display by the meddle of every class for example and put a log 
scale on the x-axis.

Thank you for your help
Best regards
Laurent



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