[R] table command
Greg Snow
Greg.Snow at imail.org
Mon Apr 26 23:01:15 CEST 2010
Is the fact that 0 is a possible and interesting value (even in being absent) a property of the table? Or a property of the variable?
I would argue that it is probably a property of the variable, and this is the better way to work with it in R (some older programs forced us to specify this at the analysis stage and it can take a bit of an effort to break that habit and do the more sensible approach).
I would convert your data to factors (or ordered factors) and specify the levels, then table just works on its own:
# untested code
> s2 <- as.data.frame( lapply(s, function(x) factor(x, levels=0:1) ) )
> table( s2[,c(1,3)] )
Hope this helps,
--
Gregory (Greg) L. Snow Ph.D.
Statistical Data Center
Intermountain Healthcare
greg.snow at imail.org
801.408.8111
> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-
> project.org] On Behalf Of Shubha Vishwanath Karanth
> Sent: Saturday, April 24, 2010 7:59 AM
> To: r-help at r-project.org; r-help at stat.math.ethz.ch
> Subject: [R] table command
>
> Hi,
>
>
>
> Let s be a dataframe.
>
>
>
> > s
>
> A B C
>
> 0 0 1
>
> 1 0 1
>
> 1 0 1
>
> 0 0 1
>
> 1 0 1
>
> 0 1 1
>
> 0 1 1
>
> 0 1 1
>
> 0 0 1
>
>
>
> > tab1=table(s[,c(1,2)])
>
> > tab1
>
> B
>
> A 0 1
>
> 0 3 3
>
> 1 3 0
>
>
>
> > tab2=table(s[,c(1,3)])
>
> > tab2
>
> C
>
> A 1
>
> 0 6
>
> 1 3
>
>
>
>
>
> The problem is I need to access frequency corresponding to (0,0).
> tab1[1] will give me the correct value while tab2[1] will not give the
> frequency which I expected. So, is there a possibility in the table
> command to have the order of tab1 and tab2 being equal? (here 2*2). May
> be by filling in the appropriate value as 0 or NA?
>
>
>
> Thanks,
>
> Shubha
>
>
>
> This e-mail may contain confidential and/or privileged
> i...{{dropped:13}}
>
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