Greetings R users,

My goal is to generate quartile groups of each variable in my data set.  I
would like each experiment to have its designated group added as a
subsequent column.  I can accomplish this individually with the following
code:

brks <- with(data_variables,

             cut2(var2, g=4))

#I don't want the actual numbers, I need a numbered group

data$test1=factor(brks, labels=1:4)


However, I cannot get a loop to work nor can I get a loop to add the
columns with an appropriate name (ex. quartile_variable).  I have tried
multiple different ways but can't seem to get it to work.  I think it would
begin something like this:


    for(i in 11:ncol(survival_data_variables)){
        brks=as.data.frame(with(survival_data_variables,
            cut2(survival_data_variables[,i], g=4)))


Any assistance would be sincerely appreciated.  I would like the final data
set to have the following layout:


ID        var1       var2        var3     var4       quartile var1
quartile var2        quartile var3      quartile var4


Here is a subset of my data to work with:

structure(list(ID = c(11112L, 11811L, 12412L, 12510L, 13111L,

20209L, 20612L, 20711L, 21510L, 22012L), var1 = c(106, 107,

116, 67, 76, 146, 89, 62, 65, 116), var2 = c(0, 0, 201,

558, 526, 555, 576, 0, 531, 649), var3 = c(70.67, 81.33,

93.67, 84.33, 52, 74, 114, 101, 80.33, 91.33), var4 = c(136,

139, 142, 138, 140, 140, 136, 139, 140, 139)), .Names = c("ID",

"var1", "var2", "var3", "var4"), row.names = c(NA,

10L), class = "data.frame")


Regards,
Charles

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