[R] Remove Indeterminate Level

[Liaw, Andy]

Try:

> sex <- factor(sample(c("M", "F"), 10, replace=TRUE), levels=c("M", "F",
"I"))
> sex
 [1] F F M F F F M M M F
Levels: M F I
> sex2 <- sex[, drop=TRUE]
> sex2
 [1] F F M F F F M M M F
Levels: M F

HTH,
Andy

> From: Neil Leonard
> 
> Hi,
> 
> I have imported some data to R from stata and my factor 
> variables have 
> an Indeterminate level which I don't really want. For example the 
> variable sex has the levels Male, Female and Indeterminate. There are 
> no 'Indeterminate' values in the data. Can somebody tell me 
> how to get 
> rid of this level as it restricting my cox ph model.
> 
> Thanks
> Neil
> 
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