median of binned values
Thank you, Chuck, would you mind commenting a bit on the code, it is not all clear... HOw would you go to retrieve only the numeric value (not the category name)? I am just starting with R, and the functionality of replicate and levels is not quite clear. I tried the documentation, but am not any wiser. What if I had a vector v <- vector(c(1,10,100,1000,10000)) and wanted to perform it on that? Thanks a lot Martin
Chuck Cleland wrote:
Martin Tomko wrote:
Dear list,
I have a vector (array, table row, whatever is best) of frequency values
for categories (or bins), and I need to find the median category.
Trivial to do by hand, but I was wondering if there is a means to do it
in R in an elegant way.
The obvious medioan(vector) returns the median frequency for the binns,
and that is not what I want. i.e,:
freq
cat1 1
cat2 10
cat3 100
cat4 1000
cat5 10000
I want it to return cat5, instead of cat3.
df <- data.frame(binname = as.factor(paste("cat", 1:5, sep="")),
freq = c(1,10,100,1000,10000))
df
binname freq
1 cat1 1
2 cat2 10
3 cat3 100
4 cat4 1000
5 cat5 10000
with(df, levels(binname)[median(rep(as.numeric(binname), freq))])
[1] "cat5"
Thanks a lot Martin
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Martin Tomko Postdoctoral Research Assistant Geographic Information Systems Division Department of Geography University of Zurich - Irchel Winterthurerstr. 190 CH-8057 Zurich, Switzerland email: martin.tomko at geo.uzh.ch site: http://www.geo.uzh.ch/~mtomko mob: +41-788 629 558 tel: +41-44-6355256 fax: +41-44-6356848