On Jun 11, 2012, at 12:29 PM, Samantha Sifleet wrote:
Hi,
I am a relatively new to R. So, this is probably a really basic
issue that
I keep hitting.
I read my data into R using the read.csv command:
x = rep("numeric", 3)
CB_un=read.csv("Corn_Belt_unirr.csv", header=TRUE,
colClasses=c("factor",
x))
# I have clearly told R that I have one factor variable and 3 numeric
variables in this table.
#but if I try to do anything with them, I get an error
boxplot(CB_un["Value"]~CB_un["State.Fips"])
Error in model.frame.default(formula = CB_un["Value"] ~
CB_un["State.Fips"]) :
invalid type (list) for variable 'CB_un["Value"]'
If you were steadfastly intent on using direct extraction in the
formula, then this would be the way to do so:
boxplot(CB_un[["Value"]]~CB_un[["State.Fips"]])
Beter would be to use the formula interface the way it was designed to
operate:
boxplot( Value ~ State.Fips, data=CB_un)
--
David.
# Because these variables are all stored as lists.
#So, I have to unpack them.
CB_unirr_rent<-as.numeric(unlist(CB_un["Value"]))
CB_unirr_State<-as.factor(unlist(CB_un["State.Fips"]))
#before I can do anything with them
boxplot(CB_unirr_rent~CB_unirr_State)
Is there a reason my data is always imported as lists?
It's in a dataframe ..... dataframes are lists
Is there a way to
skip this upacking step?
Thanks,
Sam
[[alternative HTML version deleted]]
--
David Winsemius, MD
West Hartford, CT
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