更改晶格图中y轴的比例格式

Question

Hi everybody I am making a graphic with lattice package and it works fine but I have a little problem with format of y axis. The data used for this graphic is saved in a , a list with four numeric variables and one factor variable (In the final part I add the dput version). The code used to make my graph is the next:

library(lattice)
DD=barchart(a1 ~ a5,a)
DD

I got this graphic with this code:

In this graph the scale of y axis shows the complete numbers for example 2000000, 4000000, etc. I don't know if it is possible to create a function or maybe any option to get values in y axis like these 2,000,000 until 8,000,000. The dput() version of a is the next:

structure(list(a1 = c(560492.29, 1433973.37, 3016748.66, 4241217.73, 
6251742.27, 6757161.24, 7408081.05, 7899980.33), a2 = 1:8, a3 = c(0, 
0.00793734405263048, 0.0129172080248807, 0.0324335034787285, 
0.0397094648625047, 0.0555107413716237, 0.0521541081141384, 0.0515512600016815
), a4 = c(0.0142731668976214, 0.010460445301017, 0.0928151568317925, 
0.0707344020275045, 0.0303915279604129, 0.0517968992552855, 0.0202481585970229, 
0.0253165187311296), a5 = structure(1:8, .Label = c("abr 2013", 
"may 2013", "jun 2013", "jul 2013", "ago 2013", "sep 2013", "oct 2013", 
"nov 2013"), class = "factor")), .Names = c("a1", "a2", "a3", 
"a4", "a5")) 

Many thanks for your help.

Answer 1

You can specify your custom formatter, for example:

comma_fomatter <- function (lim, logsc = FALSE, at = NULL, ...) 
{
  ans <- yscale.components.default(lim = lim, logsc = logsc, 
                                   at = at, ...)
  xx = as.numeric(ans$left$labels$labels)
  ans$left$labels$labels <- formatC(xx, format="fg",big.mark = ",")
  ans
}

Then :

barchart(a1 ~ a5,xx, yscale.components =comma_fomatter )