On Feb 10, 2010, at 2:02 PM, Soyeon Kim wrote:
> Dear All,
>
> What I want is change following data
>> data
> alc status age freq
> 1 0 0 0 408
> 2 1 0 0 64
> 3 0 1 0 26
> 4 1 1 0 30
> 5 0 0 1 258
> 6 1 0 1 45
> 7 0 1 1 78
> 8 1 1 1 66
>
> To this table.
>
> age =0
> alc
> 0 1
> status 0 408 64
> 1 26 30
>
> age =1
> alc
> 0 1
> status 0 258 45
> 1 78 66
>
> How can I do that?
>
> Thanks,
See ?xtabs
With your data in a data frame called 'DF':
> DF
alc status age freq
1 0 0 0 408
2 1 0 0 64
3 0 1 0 26
4 1 1 0 30
5 0 0 1 258
6 1 0 1 45
7 0 1 1 78
8 1 1 1 66
> xtabs(freq ~ status + alc + age, data = DF)
, , age = 0
alc
status 0 1
0 408 64
1 26 30
, , age = 1
alc
status 0 1
0 258 45
1 78 66
and you can reverse the process by using as.data.frame.table():
> as.data.frame.table(xtabs(freq ~ status + alc + age, data = DF))
status alc age Freq
1 0 0 0 408
2 1 0 0 26
3 0 1 0 64
4 1 1 0 30
5 0 0 1 258
6 1 0 1 78
7 0 1 1 45
8 1 1 1 66
HTH,
Marc Schwartz
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