[R] remove low frequent rows

[Gabor Grothendieck]

See ?ave and try this:

a[as.numeric(ave(a[,1], a[,1], FUN = length)) > 1, ]


On Sun, Aug 31, 2008 at 2:19 AM, Yuan Jian <jayuan2008 at yahoo.com> wrote:
> Hi,
>
> I have a matrix.
>>a<-cbind(c("a","b","a"),c(4,3,6))
>      [,1] [,2]
> [1,] "a"  "4"
> [2,] "b"  "3"
> [3,] "a"  "6"
>
> I want to remove rows in matrix a whose first column has frequency less than 2.
> in about example matrix a becomes
>      [,1] [,2]
> [1,] "a"  "4"
> [2,] "a"  "6"
>
>
>
>
>
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