[R] apply'ing cut to a data.set column

[Massimo Santini]

Hi all,
	there is probably something I'm still missing about how R
manipulates multivariate data. I have a dataset in which, for various 
tuples of a set of 4 parameters, a value of interest is stored:

	p1   p2   p3   p4     v
        0    0    0    0      0.2342
        0    1    1    0      0.6124
        ....
	0    0    1    1      0.1234

What I would like to do is to "cut" the "v" column of the dataset, let say
with two breaks: (0,.5] (.5,1], to obtain something like

        p1   p2   p3   p4     v
        0    0    0    0      (0,.5]
        0    1    1    0      (.5,1]
        ....
        0    0    1    1      (0,.5]

I now how to do it on data$v, using cut, but I can't see a
simple/straightforward way to do it on all the dataset, I'm confused about
tapply, sapply, lapply and firends....

Is there a place where I can find a more complete treatment of how R uses
multivariate data?

	thanks in advance for any suggestion...
							Massimo



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