On Sat, 17 Jan 2009, J?rg Gro? wrote:
Hi,
I know how to convert a factor-variable into a numeric variable via
as.numeric().
But how can I control the values that are assigned?
For example, I have this factor-variable:
z <- c("male", "male", "female")
z <- as.factor(z)
And I want to convert male in 3 and female into the numeric value 5 (just for
the example)
so that I get:
[1] 3 3 5
Like this:
z <- c("male", "male", "female")
z <- as.factor(z)
num.codes[ levels(z) ][ z ]
male male female
3 3 5
or if you want to avoid the names():
z.to.num <- unname(num.codes)[ match(levels(z),names(num.codes)) ]
z.to.num[ z ]
[1] 3 3 5
See
?as.character
?match
?levels
HTH,
Chuck
Thanks for any help!
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Charles C. Berry (858) 534-2098
Dept of Family/Preventive Medicine
E mailto:cbe...@tajo.ucsd.edu UC San Diego
http://famprevmed.ucsd.edu/faculty/cberry/ La Jolla, San Diego 92093-0901
______________________________________________
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
