Re: [R] Calculating Summaries for each level of a Categorical variable
The problem is that tapply is expecting a vector for the first argument, your first argument is a list or data frame, so the length that it sees is the number of list elements (columns of the data frame). You need to either pass a single vector, or use functions like aggregate or the plyr package to work on all the columns in a data frame. -- Gregory (Greg) L. Snow Ph.D. Statistical Data Center Intermountain Healthcare greg.s...@imail.org 801.408.8111 > -Original Message- > From: r-help-boun...@r-project.org [mailto:r-help-boun...@r- > project.org] On Behalf Of RaoulD > Sent: Saturday, June 26, 2010 10:47 PM > To: r-help@r-project.org > Subject: Re: [R] Calculating Summaries for each level of a Categorical > variable > > > Hi Corey, > > Thanks so much for this. However, I get this error for tapply - "Error > in > tapply(RT, RT$R, fun=WA): > arguments must have same length". Any idea how to get around this? > > Thanks again, > Raoul > -- > View this message in context: > http://r.789695.n4.nabble.com/Calculating-Summaries-for-each-level-of- > a-Categorical-variable-tp2269349p2269815.html > Sent from the R help mailing list archive at Nabble.com. > > __ > R-help@r-project.org mailing list > 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. __ R-help@r-project.org mailing list 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.
Re: [R] Calculating Summaries for each level of a Categorical variable
Hi Raoul,
I presume you need these summaries for a table of descriptive statistics for a
thesis/report/paper
("Table 1" as known informally by medical researchers). If this is the case,
then specify
method="reverse" to summary.formula. In the following small example, I create 4
groups of patients
and specify 2 characteristics per patient (age and gender) and use
summary.formula to summarize
characteristics by group. Running the stats on patient characteristics by group
is optional but
is included for completeness. If you are looking for something like this I
strongly advise you spent
some time fiddling around with summary.formula and read:
Harrell FE (2004): Statistical tables and plots using S and LaTeX
(available from
http://biostat.mc.vanderbilt.edu/twiki/pub/Main/StatReport/summary.pdf
The 2-3 hours you are going to need to familiarize yourself with this package
are really worth spending
for (especially if you are going to use call LaTEX on the output). If you are a
Windows user, copy and
paste the output of the print function into Excel or OpenOffice and use the
Text to Columns facilities
of the two programs to format the output into a table that can be used inside a
manuscript.
Christos
## R-code follows
library(Hmisc)
## One baseline factor (e.g. patient group)
grp<-round(runif(20,1,4))
grp<-factor(grp,labels=paste("Group",1:4))
## Another factor (e.g. sex)
sex<-round(runif(20,1,2))
sex<-factor(sex,labels=c("Male","Female"))
## A continuous variable (e.g. age)
age<-rlnorm(20,4,.1)
## A data frame
data<-data.frame(age=age,grp=grp,sex=sex)
## Table 1
sm<-summary(grp~sex+age,method="reverse",overall=T,test=T)
print(sm,dig=2,exclude1=F)
Descriptive Statistics by grp
+--+--+--+--+--+--++
| |Group 1 |Group 2 |Group 3 |Group
4 |Combined | Test |
| |(N=3) |(N=6) |(N=8)
|(N=3) |(N=20) |Statistic |
+--+--+--+--+--+--++
|sex : Male| 67% ( 2)| 67% ( 4)| 25% ( 2)|
67% ( 2)| 50% (10)|Chi-square=3.3 d.f.=3 P=0.34|
+--+--+--+--+--+--++
| Female| 33% ( 1)| 33% ( 2)| 75% ( 6)|
33% ( 1)| 50% (10)| |
+--+--+--+--+--+--++
|age | 60/62/65| 51/55/60| 46/51/57|
46/48/52| 49/54/60| F=2.9 d.f.=3,16 P=0.068 |
+--+--+--+--+--+--++
> Date: Sat, 26 Jun 2010 21:48:05 -0700
> From: raoul.t.dso...@gmail.com
> To: r-help@r-project.org
> Subject: Re: [R] Calculating Summaries for each level of a Categorical
> variable
>
>
> Hi Christos,
>
> Thanks for this. I had a look at Summary.Forumla in the Hmisc package and it
> is extremely complicated for me. Still trying to decipher how I could use
> it.
>
> Regards,
> Raoul
> --
> View this message in context:
> http://r.789695.n4.nabble.com/Calculating-Summaries-for-each-level-of-a-Categorical-variable-tp2269349p2269816.html
> Sent from the R help mailing list archive at Nabble.com.
>
> __
> R-help@r-project.org mailing list
> 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.
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Re: [R] Calculating Summaries for each level of a Categorical variable
I'd suggest using the functions within the Hmisc and plyr packages: library(Hmisc); library(plyr) df=data.frame(v1=rnorm(10), v2=rnorm(10), wt=sample(1:5,rep=T),sex=rep(0:1,each=5)); df ddply(df,~sex,summarise,v1.avg=wtd.mean(v1,wt),v2.avg=wtd.mean(v2,wt)) hope this helps, david freedman -- View this message in context: http://r.789695.n4.nabble.com/Calculating-Summaries-for-each-level-of-a-Categorical-variable-tp2269349p2270001.html Sent from the R help mailing list archive at Nabble.com. __ R-help@r-project.org mailing list 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.
Re: [R] Calculating Summaries for each level of a Categorical variable
the variable you want to analyze (first argument to tapply) and the variable you want to analyze by (the factor, second arg to tapply) both must have the same number of rows, that' s how I read this. CS Corey Sparks Assistant Professor Department of Demography and Organization Studies College of Public Policy 501 West Durango Blvd Monterrey Building 2.270C San Antonio, TX 78207 corey.sparks 'at' utsa.edu 210 458 3166 On Jun 26, 2010, at 11:46 PM, RaoulD [via R] wrote: > Hi Corey, > > Thanks so much for this. However, I get this error for tapply - > "Error in tapply(RT, RT$R, fun=WA): > arguments must have same length". Any idea how to get around this? > > Thanks again, > Raoul > > View message @ > http://r.789695.n4.nabble.com/Calculating-Summaries-for-each-level-of-a-Categorical-variable-tp2269349p2269815.html > To unsubscribe from Re: Calculating Summaries for each level of a > Categorical variable, click here. > - Corey Sparks, PhD Assistant Professor Department of Demography and Organization Studies University of Texas at San Antonio 501 West Durango Blvd Monterey Building 2.270C San Antonio, TX 78207 210-458-3166 corey.sparks 'at' utsa.edu https://rowdyspace.utsa.edu/users/ozd504/www/index.htm -- View this message in context: http://r.789695.n4.nabble.com/Calculating-Summaries-for-each-level-of-a-Categorical-variable-tp2269349p2269988.html Sent from the R help mailing list archive at Nabble.com. [[alternative HTML version deleted]] __ R-help@r-project.org mailing list 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.
Re: [R] Calculating Summaries for each level of a Categorical variable
You could try the remix function in remix package. David Le 27 juin 2010 à 06:48, RaoulD a écrit : > > Hi Christos, > > Thanks for this. I had a look at Summary.Forumla in the Hmisc > package and it > is extremely complicated for me. Still trying to decipher how I > could use > it. > > Regards, > Raoul > -- > View this message in context: > http://r.789695.n4.nabble.com/Calculating-Summaries-for-each-level-of-a-Categorical-variable-tp2269349p2269816.html > Sent from the R help mailing list archive at Nabble.com. > > __ > R-help@r-project.org mailing list > 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. __ R-help@r-project.org mailing list 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.
Re: [R] Calculating Summaries for each level of a Categorical variable
Hi Corey, Thanks so much for this. However, I get this error for tapply - "Error in tapply(RT, RT$R, fun=WA): arguments must have same length". Any idea how to get around this? Thanks again, Raoul -- View this message in context: http://r.789695.n4.nabble.com/Calculating-Summaries-for-each-level-of-a-Categorical-variable-tp2269349p2269815.html Sent from the R help mailing list archive at Nabble.com. __ R-help@r-project.org mailing list 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.
Re: [R] Calculating Summaries for each level of a Categorical variable
Hi Christos, Thanks for this. I had a look at Summary.Forumla in the Hmisc package and it is extremely complicated for me. Still trying to decipher how I could use it. Regards, Raoul -- View this message in context: http://r.789695.n4.nabble.com/Calculating-Summaries-for-each-level-of-a-Categorical-variable-tp2269349p2269816.html Sent from the R help mailing list archive at Nabble.com. __ R-help@r-project.org mailing list 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.
Re: [R] Calculating Summaries for each level of a Categorical variable
Look at the summary.formula function inside package Hmisc
Christos
> Date: Sat, 26 Jun 2010 05:17:34 -0700
> From: raoul.t.dso...@gmail.com
> To: r-help@r-project.org
> Subject: [R] Calculating Summaries for each level of a Categorical variable
>
>
> Hi,
>
> I have a dataset which has a categorical variable "R",a count variable C
> (integer) and 4 or more numeric variables (A,T,W,H - integers) containing
> measures for "R". I would like to summarize each level of the variable R by
> the average for A,T,W and H.
>
> I have written a function to calculate weighted averages using C as the
> weight and this is given below. The function works perfectly but how do I
> add the additional dimension I require to this function?
>
> Dataset: RT=
> R A T W H
> R1 10 20 20 10
> R2 60 20 50 10
> R3 45 10 20 50
> R4 68 50 20 10
> R1 73 20 40 46
> R3 25 30 10 54
> R3 36 90 20 10
> R2 29 10 30 30
>
> # FUNCTION TO CALCULATE THE WEIGHTED AVERAGE FOR A WEIGHTED BY C
> WA<-function(A,C) {
> sp_A<-c(A %*% C)
> sum_C<-sum(C)
> WA<-sp_A/sum_C
> return(WA)
> }
>
> I am trying to incorporate the additional step of calculating the weighted
> average of A,T,W and H for each level of R. Need help with this.
>
> Thanks in advance!
> Raoul
> --
> View this message in context:
> http://r.789695.n4.nabble.com/Calculating-Summaries-for-each-level-of-a-Categorical-variable-tp2269349p2269349.html
> Sent from the R help mailing list archive at Nabble.com.
>
> __
> R-help@r-project.org mailing list
> 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.
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[R] Calculating Summaries for each level of a Categorical variable
Hi,
I have a dataset which has a categorical variable "R",a count variable C
(integer) and 4 or more numeric variables (A,T,W,H - integers) containing
measures for "R". I would like to summarize each level of the variable R by
the average for A,T,W and H.
I have written a function to calculate weighted averages using C as the
weight and this is given below. The function works perfectly but how do I
add the additional dimension I require to this function?
Dataset: RT=
R A T W H
R1 10 20 20 10
R2 60 20 50 10
R3 45 10 20 50
R4 68 50 20 10
R1 73 20 40 46
R3 25 30 10 54
R3 36 90 20 10
R2 29 10 30 30
# FUNCTION TO CALCULATE THE WEIGHTED AVERAGE FOR A WEIGHTED BY C
WA<-function(A,C) {
sp_A<-c(A %*% C)
sum_C<-sum(C)
WA<-sp_A/sum_C
return(WA)
}
I am trying to incorporate the additional step of calculating the weighted
average of A,T,W and H for each level of R. Need help with this.
Thanks in advance!
Raoul
--
View this message in context:
http://r.789695.n4.nabble.com/Calculating-Summaries-for-each-level-of-a-Categorical-variable-tp2269349p2269349.html
Sent from the R help mailing list archive at Nabble.com.
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Re: [R] Calculating Summaries for each level of a Categorical variable
Did you try tapply? ?tapply tapply(RT, RT$R, fun=WA) or something like that - Corey Sparks, PhD Assistant Professor Department of Demography and Organization Studies University of Texas at San Antonio 501 West Durango Blvd Monterey Building 2.270C San Antonio, TX 78207 210-458-3166 corey.sparks 'at' utsa.edu https://rowdyspace.utsa.edu/users/ozd504/www/index.htm -- View this message in context: http://r.789695.n4.nabble.com/Calculating-Summaries-for-each-level-of-a-Categorical-variable-tp2269349p2269444.html Sent from the R help mailing list archive at Nabble.com. __ R-help@r-project.org mailing list 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.
