[R] add factor to dataframe given ranges
Marc Schwartz (via MN)
mschwartz at mn.rr.com
Thu Dec 22 17:08:08 CET 2005
On Thu, 2005-12-22 at 16:58 +0100, Albert Vilella wrote:
> Hi all,
> I would like to factorize the entries in a dataframe given some
> groupings. E.g:
> mydf = data.frame(
> a = rnorm(100,10),
> b = rnorm(100,10),
> c = rgamma(100, 1, scale=1))
> group = hist(mydf$c, breaks="FD")
> The idea is to create a factor "mydf$d" with levels corresponding to
> the ranges in group$breaks.
> There must be an easy way to do this that I haven't found out.
> Thanks in advance,
myfac.c <- cut(mydf$c, breaks = group$breaks)
Take note of the additional arguments in cut() relative to the nature of
the interval cutpoints (ie. 'right' and 'include.lowest').
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