[R] Aggregate to find majority level of a factor

[Martin Henry H. Stevens]

How about tapply?

plot <- gl(2,3); plot
type <- letters[c(1,2,2,1,1,1)]; type
tapply(type, list(plot), function(x) {tabl <- table(x)
                                                 names(tabl[tabl==max 
(tabl)])})

Hank

On May 31, 2007, at 3:25 PM, Thompson, Jonathan wrote:

> I want to use the aggregate function to summarize data by a factor (my
> field plots), but I want the summary to be the majority level of  
> another
> factor.
>
>
> For example, given the dataframe:
>
> Plot1     big
> Plot1     big
> Plot1     small
> Plot2     big
> Plot2     small
> Plot2     small
> Plot3     small
> Plot3     small
> Plot3     small
>
>
> My desired result would be:
> Plot1 big
> Plot2 small
> Plot3 small
>
>
> I can't seem to find a scalar function that will give me the majority
> level.
>
> Thanks in advance,
>
> Jonathan Thompson
>
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Dr. Hank Stevens, Assistant Professor
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Botany Department
Miami University
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