[R] Calculating First Occurance by a factor

[hadley wickham]

On Wed, Apr 1, 2009 at 11:00 AM, hadley wickham <h.wickham at gmail.com> wrote:
>> I tried messing with the line df$FixTime[which.min(df$FixInx)] changing it
>> to df[which.min(df$FixInx)] or adding new lines with the additional columns
>> that I want to include, but nothing seemed to work. I'll admit I only have a
>> mild understanding of what is going on with the function .fun. :-)
>
> You probably want:
>
> df[which.min(df$FixInx), ]

Or alternatively:

ddply(data, .(Sub, Tr, IA), subset, FixInx == min(FixInx))

which might be a bit easier to understand.

Hadley

-- 
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