Hi Jim

Thanks for reply but this is not working. I think I am missing something
over here.

1> x <- cbind(c(1,2,2,2,3,4), c('a','b', 'c','d','e','f'))
1> colnames(x) = c('param', 'case1')
1> x = as.data.frame(x)
1> x
  param case1
1     1     a
2     2     b
3     2     c
4     2     d
5     3     e
6     4     f
1> x[
1+      , list(case1 = paste(x$case1, collapse = ','))
1+      , by = x$param
1+   ]
Error in `[.data.frame`(x, , list(case1 = paste(x$case1, collapse = ",")),
 :
  unused argument(s) (by = x$param)


Hi David.
Thanks a lot for your help.

1> aggregate(x$case1, x['param'], FUN = paste, collapse=",")
  param     x
1     1     a
2     2 b,c,d
3     3     e
4     4     f
1>


Thanks again
M


On Wed, Dec 21, 2011 at 11:56 AM, David Winsemius <dwinsemius@comcast.net>wrote:

>
> On Dec 21, 2011, at 11:31 AM, jim holtman wrote:
>
>  Here is an example using 'data.table'"
>>
>>  x <- read.table(text = "param       case1
>>>
>> + 1               a
>> + 2               b
>> + 2               c
>> + 2               d
>> + 3               e
>> + 4               f", header = TRUE, as.is = TRUE)
>>
>
> And the aggregate version:
>
> > aggregate(x$case1, x["param"], FUN=paste, collapse=",")
>  param     x
> 1     1     a
> 2     2 b,c,d
> 3     3     e
> 4     4     f
>
> ( Generally one uses the "[[" function for extraction, but using  "["
> returns a list which is what aggregate is designed to process as its second
> argument, whereas you would get an error with either of these:
>
> aggregate(x$case1, x$param, FUN=paste, collapse=",")
> aggregate(x$case1, x[["param"]], FUN=paste, collapse=",")
>
>  )
>
>  require(data.table)
>>> x <- data.table(x)
>>> x[
>>>
>> +     , list( case1 = paste(case1, collapse = ','))
>> +     , by = param
>> +  ]
>>    param case1
>> [1,]     1     a
>> [2,]     2 b,c,d
>> [3,]     3     e
>> [4,]     4     f
>>
>>>
>>>
>>
>> On Wed, Dec 21, 2011 at 11:26 AM, Mary Kindall <mary.kindall@gmail.com>
>> wrote:
>>
>>> Hi
>>> I have a data frame with values in following format.
>>>
>>>
>>> param       case1
>>> 1               a
>>> 2               b
>>> 2               c
>>> 2               d
>>> 3               e
>>> 4               f
>>>
>>>
>>> how to use aggregate so that it I only one row for each 'param' value.
>>>
>>> the output for the above input should be
>>>
>>> param     case1
>>> 1      a
>>> 2      b,c,d
>>> 3      e
>>> 4      f
>>>
>>> Thanks
>>> M
>>>
>>>
>>>
>>> --
>>> -------------
>>> Mary Kindall
>>> Yorktown Heights, NY
>>> USA
>>>
>>>       [[alternative HTML version deleted]]
>>>
>>> ______________________________**________________
>>> R-help@r-project.org mailing list
>>> https://stat.ethz.ch/mailman/**listinfo/r-help<https://stat.ethz.ch/mailman/listinfo/r-help>
>>> PLEASE do read the posting guide http://www.R-project.org/**
>>> posting-guide.html <http://www.R-project.org/posting-guide.html>
>>> and provide commented, minimal, self-contained, reproducible code.
>>>
>>
>>
>>
>> --
>> Jim Holtman
>> Data Munger Guru
>>
>> What is the problem that you are trying to solve?
>> Tell me what you want to do, not how you want to do it.
>>
>> ______________________________**________________
>> R-help@r-project.org mailing list
>> https://stat.ethz.ch/mailman/**listinfo/r-help<https://stat.ethz.ch/mailman/listinfo/r-help>
>> PLEASE do read the posting guide http://www.R-project.org/**
>> posting-guide.html <http://www.R-project.org/posting-guide.html>
>> and provide commented, minimal, self-contained, reproducible code.
>>
>
> David Winsemius, MD
> West Hartford, CT
>
>


-- 
-------------
Mary Kindall
Yorktown Heights, NY
USA

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