[R] contingency table, several variables from dataframe
Birgitle
birgit.lemcke at systbot.uzh.ch
Thu Oct 2 13:40:30 CEST 2008
Thanks for your answer.
It is intended, that the variables are treated as class factor, because
these are binary variables with, for example, the presence or the absence of
a plant organ.
As far as I understood, I have to treat them for other calculations as
factor. Therefore I classified these variables as factors in my original
dataframe.
If I do what you suggested, I have to change the classes of all my
variables. Is there a possibility to do something similar without changing
the classes?
B.
Eik Vettorazzi wrote:
>
> First of all your construction of ABC leads to a structure with 3 factor
> variables due to the way cbind processes the input variables - which is
> not intended I think.
>
> You can do sth like
>
> ABC<-data.frame(A,B,C)
> aggregate(ABC[,2:3],by=list(A),sum)
>
> hth.
>
> Birgitle schrieb:
>> Hello R-Users!
>>
>> I need a little help to build up a contingency table out of several
>> variables.
>>
>> A<-c("F","M","M","F","F","F","F","M","F","M","F","F")
>> B<-c(0,0,0,0,0,0,1,1,1,1,0,1)
>> C<-c(0,1,1,1,1,1,1,1,1,0,0,0)
>>
>> ABC<-as.data.frame(cbind(A,B,C))
>>
>> ABC
>>
>> A B C
>> 1 F 0 0
>> 2 M 0 1
>> 3 M 0 1
>> 4 F 0 1
>> 5 F 0 1
>> 6 F 0 1
>> 7 F 1 1
>> 8 M 1 1
>> 9 F 1 1
>> 10 M 1 0
>> 11 F 0 0
>> 12 F 1 0
>>
>> I would like to count in each variable B and C the frequencies for M and
>> F
>> (variable A) and finally get the following table:
>>
>> B C
>> F 3 5
>>
>> M 2 3
>>
>> Is there a function that can do that in one step?
>> Tried ?structable, ?ftable, ?xtabs, ?table but could not get what I would
>> like to have.
>>
>> Maybe I did not use the tried functions in the right way.
>>
>> Many thanks in advance for any help.
>>
>> B.
>>
>>
>>
>> -----
>> The art of living is more like wrestling than dancing.
>> (Marcus Aurelius)
>>
>
> --
> Eik Vettorazzi
> Institut für Medizinische Biometrie und Epidemiologie
> Universitätsklinikum Hamburg-Eppendorf
>
> Martinistr. 52
> 20246 Hamburg
>
> T ++49/40/42803-8243
> F ++49/40/42803-7790
>
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>
-----
The art of living is more like wrestling than dancing.
(Marcus Aurelius)
--
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