[R] Summarizing select columns in a data frame

[Bernard Comcast]

Thanks Bert

Bernard
Sent from my iPhone so please excuse the spelling!"

> On Jan 17, 2021, at 3:48 PM, Bert Gunter <bgunter.4567 using gmail.com> wrote:
> 
> 
> There are literally tons of ways to do this sort of thing in R.
> 
> In base R ?tapply and friends, especially ?ave and ?by that may be close to what you want.
> But there is a whole parallel universe -- the so-called "tidyverse set of packages -- that many folks prefer.
> This link takes you down that rabbit hole: https://dplyr.tidyverse.org/
> 
> There are still others (e.g. the data.table package). You should expect to invest a little time in learning whichever you choose. You may wish to also search a bit for tutorials on your choice -- there are many good ones out there.
> 
> 
> Bert Gunter
> 
> "The trouble with having an open mind is that people keep coming along and sticking things into it."
> -- Opus (aka Berkeley Breathed in his "Bloom County" comic strip )
> 
> 
>> On Sun, Jan 17, 2021 at 12:18 PM Bernard McGarvey <mcgarvey.bernard using comcast.net> wrote:
>> I have a data frame that consists of several factor columns say A, B, C, D, and E and several columns containing numerical data, say X1, X2, .... X10. I would like to create statistics of some of the numerical columns by some of the factor columns. For example,
>> 
>> Calculate the mean, min, and max of variables X1 and X7, by factors A, and E. The results should look like the table below:
>> 
>> Factor A Factor E     mean(X1) min(x1) max(X1) mean(X7) min(x7) max(X7) mean(X10) min(x10) max(X10)
>> A1        E1
>> A1        E2
>> A1        E3
>> A2        E1
>> A2        E2
>> A2        E3
>> 
>> I would like the results to be returned to a data frame or other object that I can write out using the write.csv function. I have looked at the summarize and numSummary functions but they do not appear to be flexible enough to do the above.
>> 
>> Any help would be appreciated,
>> 
>> Thanks
>> 
>> Bernard McGarvey
>> Director, Fort Myers Beach Lions Foundation, Inc.
>> Retired (Lilly Engineering Fellow).
>> 
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