[R] How to Un-group a grouped data set?

[R. Michael Weylandt]

Sorry -- I missed the bit about the AE in your original post. Perhaps
you can work with my bit for the repeats, but it looks like if you
want to use your function, it should suffice to do something like

do.call("rbind", lapply(NewFuncName, 1:6))

Best,
Michael

On Tue, May 15, 2012 at 1:50 AM, R. Michael Weylandt
<michael.weylandt at gmail.com> wrote:
> Don't use subset for a function name -- it's already the name of a
> rather important function as is data (but at least that one's not a
> function in your use so it's not quite so bad). Finally, use dput()
> when sending data so we get a plaintext reproducible version.
>
> I'd try something like this:
>
> dats <- structure(list(Study = c(1L, 1L, 2L, 2L, 3L, 3L), TX = c(1L,
> 0L, 1L, 0L, 1L, 0L), AEs = c(3L, 2L, 1L, 2L, 1L, 1L), N = c(5L,
> 7L, 10L, 7L, 8L, 4L)), .Names = c("Study", "TX", "AEs", "N"), class =
> "data.frame", row.names = c("1",
> "2", "3", "4", "5", "6"))
>
> # See how handy dput can be :-)
>
> dats[unlist(mapply(FUN = function(x,y) rep(x, y), 1:NROW(dats), dats$N)), -4]
>
> which isn't super elegant, but others might have something better.
>
> Best,
> Michael
>
> On Tue, May 15, 2012 at 1:24 AM, Cheenghee AM Koh <sigontw at gmail.com> wrote:
>> Hello, R-fellows,
>>
>> I have a question that I really don't know how to solve. I have spent hours
>> on line surfing for possible solutions but in veil. Please if anyone could
>> help me handle this issue, you would be so appreciated!
>>
>> I have a "grouped" dataset like this:
>>
>>> data
>>  Study TX AEs   N
>> 1     1     1    3       5
>> 2     1     0    2       7
>> 3     2     1    1      10
>> 4     2     0    2       7
>> 5     3     1    1       8
>> 6     3     0    1       4
>>
>> where Study is the study id, TX is treatment, AEs is how many people in
>> this trial is positive, and N is the number of the subjects. Therefore, for
>> the row 1, it stands for: It is the treatment arm for the study one, where
>> there are 5 subjects and 3 of them are positive. The row 2 stands for: It
>> is the control arm of the study 1 where there are 7 subjects and 2 of them
>> are positive.
>>
>> Now I would like to "un-group them", make it like:
>>
>> Study  TX   AEs
>>   1         1      1
>>   1         1      1
>>   1         1      1
>>   1         1      0
>>   1         1      0
>>   1         0      1
>>   1         0      1
>>   1         0      0
>>   1         0      0
>>   1         0      0
>>   1         0      0
>>   1         0      0
>>   2         1      1
>>   .....................
>>  .....................
>>
>>
>> But I wasn't able to do it. In fact I wrote a small function, and use
>> "lapply" to get what I want. It worked well, and did give me what I want.
>> But I wasn't able to collapse all the returns into one single data frame
>> for subsequent analysis.
>>
>> The function I wrote:
>>
>> subset = function(i){
>> d = c(rep(data[i,1], data[i,4]), rep(data[i,2], data[i,4]), rep(0:1,
>> c(data[i,4] - data[i,3],data[i,3])))
>> d = matrix(d, data[i,4],3)
>> d
>> }
>>
>> then:
>>
>> Data = lapply(1:6, subset)
>> Data
>>
>> Therefore, I tried to write a loop. But no matter how I tried, I can't get
>> what I want.
>>
>> Any idea?
>>
>> Thank you so much!
>>
>> Best,
>>
>>
>> --
>> Cheenghee Masaki Koh, MSW, MS(c), PhD Student
>> School of Social Service Administration
>> Department of Health Studies, Division of Biological Science
>> University of Chicago
>>
>>        [[alternative HTML version deleted]]
>>
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