I think it makes a difference if I want to use a classification method like
rpart () or if I use a modelling approach like glm().
Many thanks for the kind and fast help. I am still very untrained and it is
difficult for me to create such codes.
B.
Eik Vettorazzi wrote:
>
> Ok, then treat them as factors - but if they are really binary and coded
> 0 and 1, which kind of calculation would lead to different results for a
> "factor" instead of a numeric variable?
>
> Anyway,
>
> ABC<-as.data.frame(cbind(A,B,C))
> aggregate(ABC[,2:3],by=list(A),FUN=function(x)sum(x=='1')) # '1' is
> here the level of the corresponding factor to be counted.
>
> will work. A more sophisticated version could include some "factor to
> numeric" conversion, see FAQ 7.10.
> hth.
>
> Birgitle schrieb:
>> 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
>>>
>>> ______________________________________________
>>> R-help@r-project.org mailing list
>>> https://stat.ethz.ch/mailman/listinfo/r-help
>>> PLEASE do read the posting guide
>>> http://www.R-project.org/posting-guide.html
>>> and provide commented, minimal, self-contained, reproducible code.
>>>
>>>
>>>
>>
>>
>> -----
>> 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
>
> ______________________________________________
> R-help@r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>
>
-----
The art of living is more like wrestling than dancing.
(Marcus Aurelius)
--
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