I have quite a complicated problem that's hard to describe.
Suppose I have a dataframe d. I want to access the vector d$var, where
var is one of the variables in d. Just take for granted that there's a
good reason I want to do this as follows.
var<-"DeOxyA"
xx<-paste("d$",var, sep="")
mean(xx)
[1] NA
Warning message:
In mean.default(xx) : argument is not numeric or logical: returning NA
> mean(d$DeOxyA)
[1] 21.98904
How can I convert xx so I can do mean(xx), for example? Currently xx
is a character, not a variable.
as.numeric doesn't do it. I want R to see
mean(DeOxyA), not
mean("DeOxyA")
I'm stumped.
Thanks very much for any help.
Bill
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