On 22/06/2012 09:41, Stuart Leask wrote:
Removing rows with NAs, using na.omit(), doesn't seem to be working for me.
It won't if NA is a level of the factor, which is what you seems to have
here. For
> table(as.factor(c(1,2,NA)))
1 2
1 1
omits NAs by default.
Dataset:
str ( ex10s )
'data.frame': 2189576 obs. of 5 variables:
$ LOPNR : int 58 58 58 58 64 64 64 64 64 64 ...
$ DIAGNOS: Factor w/ 173 levels "F20","F200","F2000",..: 128 128 128 128 105
105 105 160 105 105 ...
$ X_DATE : int 20060821 20061207 20080102 20090904 20010327 20010925 20020307
20021007 20021007 20030320 ...
$ SOURCE : int 2 2 2 2 2 2 2 2 2 1 ...
$ dg : Factor w/ 7 levels "0","1","2","3",..: 6 6 6 6 5 5 5 6 5 5 ...
The only NAs are in the factor dg (put in by 'recode' from the car library; I'm
trying to eliminate cases with particular factor levels)
table ( ex10s$dg )
0 1 2 3 4 5 NA
2851 271501 63112 98425 335593 1257299 160795
So, I remove the rows with NAs, to a new dataframe ex10ss:
ex10ss<-na.omit(ex10s)
Check all the NAs have been removed:
table(ex10ss$dg)
0 1 2 3 4 5 NA
2851 271501 63112 98425 335593 1257299 160795
dim(ex10s)
[1] 2189576 5
dim(ex10ss)
[1] 2189576 5
Nothing seems to have changed. I want all the rows with NA in removed.
I am clearly doing something wrong.
The only alternative I could find is pretty similar:
use <- complete.cases ( ex10 )
ex10ss<-ex10s[use,]
which leads to the same result.
Stuart
Dr Stuart John Leask DM FRCPsych MB Mchir
Clinical Senior Lecturer and Honorary Consultant Pychiatrist
Institute of Mental Health, Innovation Park
Triumph Road, Nottingham, Notts. NG7 2TU. UK
Tel. +44 115 82 30419
stuart.le...@nottingham.ac.uk<mailto:stuart.le...@nottingham.ac.uk>
Google 'Dr Stuart Leask'
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Brian D. Ripley, rip...@stats.ox.ac.uk
Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/
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