R help - Jan 2021 - Summarizing select columns in a data frame

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).

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 at 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).
>
> ______________________________________________
> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>
	[[alternative HTML version deleted]]

On 1/17/21 12:15 PM, Bernard McGarvey 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.

The `aggregate` function will do the subsetting and function application.

 > dfrm <- cbind(dfrm, matrix(rnorm(600), ncol=10 ) ); names(dfrm)[3:12] 
<- paste0("X", 1:10)
 > str(dfrm)
'data.frame':??? 60 obs. of? 12 variables:
 ?$ Factor_A: Factor w/ 2 levels "A1","A2": 1 1 1 2 2 2 1 1
1 2 ...
 ?$ Factor_B: Factor w/ 3 levels "E1","E2","E3": 1
2 3 1 2 3 1 2 3 1 ...
 ?$ X1????? : num? -0.02116 -0.00049 0.12875 -0.05412 0.51886 ...
 ?$ X2????? : num? 1.6799 -0.0963 -0.5727 -0.3638 -0.322 ...
 ?$ X3????? : num? -0.349 0.267 -0.666 -0.329 0.902 ...
 ?$ X4????? : num? 0.1125 -0.5384 0.0924 0.6849 -0.4194 ...
 ?$ X5????? : num? -0.421 0.372 1.316 1.323 -0.03 ...
 ?$ X6????? : num? -0.0767 1.4972 0.1967 -0.7092 -1.0943 ...
 ?$ X7????? : num? 0.1771 -0.2136 -1.0818 -0.0671 2.0015 ...
 ?$ X8????? : num? 1.456 -0.383 -0.47 0.965 0.569 ...
 ?$ X9????? : num? -1.795 -0.4546 0.0069 1.2245 -0.395 ...
 ?$ X10???? : num? -1.931 1.708 0.274 0.73 -0.995 ...



 ?aggregate(? dfrm[ ,? c("X1", "X7", "X10")],??? #
columns to analyze

 ? ? ? ? ? ? ? ? ? ? ? dfrm[ c("Factor_A", "Factor_B")],? #
classifying
columns

 ????????????????????? FUN=function (x) c(mn =mean(x), min=min(x), 
max=max(x) ) )? # desired "summarizers"

#--- result----

 ? Factor_A Factor_B??????? X1.mn?????? X1.min?????? X1.max X7.mn????? 
X7.min????? X7.max
1?????? A1?????? E1? 0.187513792 -0.866094155? 2.310960164 0.22489729 
-0.91442493? 1.94095786
2?????? A2?????? E1? 0.078361707 -1.515410191? 1.382420050 -0.51309155 
-1.67026123? 0.70869034
3?????? A1?????? E2 -0.267416858 -1.995131138? 1.392115793 -0.04772929 
-2.45426692? 2.02225946
4?????? A2?????? E2 -0.069807208 -0.703073589? 1.879448658 -0.37770923 
-2.66221239? 2.00152154
5?????? A1?????? E3 -0.007800886 -1.297561250? 1.216627848 -0.30395411 
-1.08181218? 1.09764895
6?????? A2?????? E3 -0.054466856 -1.577891927? 1.674719118 0.35594015 
-1.20865279? 2.25765422
 ????? X10.mn??? X10.min??? X10.max
1 -0.3458888 -2.0312811? 1.1483179
2 -0.1021727 -1.3230372? 0.8045472
3? 0.3514645 -3.2334010? 1.7075298
4 -0.4988984 -2.1091311? 0.5857192
5? 0.2297461 -1.1336967? 0.8483935

6? 0.3700621 -1.5609424? 2.2792024


-- 

David
>
> Any help would be appreciated,
>
> Thanks
>
> Bernard McGarvey
> Director, Fort Myers Beach Lions Foundation, Inc.
> Retired (Lilly Engineering Fellow).
>
> ______________________________________________
> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.