[R] by Function Result Factor Levels

[William Dunlap]

Do you want something like the following?

> library(dplyr, quietly=TRUE, warn.conflicts=FALSE)
> warpbreaks %>% group_by(wool, tension) %>% summarize(Min=min(breaks), Median=median(breaks), Max=max(breaks))
Source: local data frame [6 x 5]
Groups: wool

  wool tension Min Median Max
1    A       L  25     51  70
2    A       M  12     21  36
3    A       H  10     24  43
4    B       L  14     29  44
5    B       M  16     28  42
6    B       H  13     17  28

Bill Dunlap
TIBCO Software
wdunlap tibco.com


On Tue, Sep 15, 2015 at 7:00 PM, Dario Strbenac
<dstr7320 at uni.sydney.edu.au> wrote:
> Good day,
>
> How is it possible to get a data.frame of factor levels used for obtaining each element of the result of the by function ? For example,
>
> result <- by(warpbreaks[, 1],   warpbreaks[, -1], summary)
>> result
> wool: A
> tension: L
>    Min. 1st Qu.  Median    Mean 3rd Qu.    Max.
>   25.00   26.00   51.00   44.56   54.00   70.00
>  ...
>
> I'd like to obtain a data.frame of the two columns, wool and tension, specifying the level of each factor that corresponds to each element of result.
>
> --------------------------------------
> Dario Strbenac
> PhD Student
> University of Sydney
> Camperdown NSW 2050
> Australia
>
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