[R] aggregate function

[jim holtman]

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)
> 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 at 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]]
>
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-- 
Jim Holtman
Data Munger Guru

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