On Dec 4, 2009, at 11:55 AM, Allen L wrote:
Dear R forum,
I want to replace all the elements in a data frame (dd) which match
the
character "x" with "0".
What's the most elegant way of doing this (there must be an easy way
which
I've missed)? I settled on the following loop:
for(i in 5:12){ # These are the column of dd I am
interested
in
dd[which(dd[,i]=="x"),i]<-0
}
The problem with this is that the columns which used to contain "x"
are
still considered factors and I am unable to coerce them into numeric:
Converting the labels of fac.obj (a factor object) to numeric values
is a FAQ (I forget the number, 7.<something>)
as.numeric(as.character( fac.obj ))
Factors are internally sets of numbers, but those numbers are not
generally what people assign meaning to, and certainly not in your
case where you assigned the character "0" to those rows where the
labels were previously "x".
mean.species.biomass<-colMeans(as.numeric(dd.p[,5:12]))
Error in inherits(x, "data.frame") :
(list) object cannot be coerced to type 'double'
I'm tried unclassing & reclassing, other functions etc. but nothing
seems to
work. What is wrong?
Thanks in advance,
Allen
--
--
David Winsemius, MD
Heritage Laboratories
West Hartford, CT
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