R help - Dec 2013 - Mean: category wise within a data frame

Hello all

I have a table a sample of which is as follows:




	
	
	
	



	
	
	
	
		
			Categories

		
		
			Variable (x)

		
		
			Frequencies

		
	
	
		
			1

			1

			1

			1

			1

		
		
			0.009

			0.867

			0.567

			0.765

			0.445

		
		
			1003

			1200

			987

			134

			890

		
	
	
		
			2

			2

			2

			2

			2

		
		
			0.007

			0.768

			0.789

			0.544

			0.987

		
		
			899

			707

			865

			678

			889

		
	
	
		
			3

			3

			3

			3

			3

		
		
			0.898

			0.887

			0.560

			0.098

			0.987

		
		
			544

			677

			934

			467

			876

		
	
	
		
			40

			40

			40

			40

			40

		
		
			0.786

			0.342

			0.456

			0.987

			0.123

		
		
			843

			987

			675

			467

			223

		
	



Basically I have 40 categories and each category has several hundred variables.
I want to calculate the average per category, that is variable *
frequency/Summation of frequencies. I want to do it for each category
separately. Since i have many categories i do not want to use the subset()
function 40 times. Is it possible to do it within a single data frame?

Really appreciate any help. Thank you.
 		 	   		  
	[[alternative HTML version deleted]]

Please do not use html formatting in your messages to the list.
The format codes are stripped and you table becomes a single
long column (see below). Only use plain text emails and use the
results of dput(mydata) to insert your data into the message.

As to your question. Look at the aggregate() function:

?aggregate

David Carlson

-----Original Message-----
From: r-help-bounces at r-project.org
[mailto:r-help-bounces at r-project.org] On Behalf Of Nandini
Jayakumar
Sent: Tuesday, December 24, 2013 4:36 AM
To: r-help at r-project.org
Subject: [R] Mean: category wise within a data frame

Hello all

I have a table a sample of which is as follows:




	
	
	
	



	
	
	
	
		
			Categories

		
		
			Variable (x)

		
		
			Frequencies

		
	
	
		
			1

			1

			1

			1

			1

		
		
			0.009

			0.867

			0.567

			0.765

			0.445

		
		
			1003

			1200

			987

			134

			890

		
	
	
		
			2

			2

			2

			2

			2

		
		
			0.007

			0.768

			0.789

			0.544

			0.987

		
		
			899

			707

			865

			678

			889

		
	
	
		
			3

			3

			3

			3

			3

		
		
			0.898

			0.887

			0.560

			0.098

			0.987

		
		
			544

			677

			934

			467

			876

		
	
	
		
			40

			40

			40

			40

			40

		
		
			0.786

			0.342

			0.456

			0.987

			0.123

		
		
			843

			987

			675

			467

			223

		
	



Basically I have 40 categories and each category has several
hundred variables. I want to calculate the average per category,
that is variable * frequency/Summation of frequencies. I want to
do it for each category separately. Since i have many categories
i do not want to use the subset() function 40 times. Is it
possible to do it within a single data frame?

Really appreciate any help. Thank you.
 		 	   		  
	[[alternative HTML version deleted]]

______________________________________________
R-help at 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.

HI,
May be this helps:


Please use ?dput() to show the example dataset
dat1 <- read.table(text="Categories? Variable Frequencies
1 0.009 1003
1 0.867 1200
1 0.567 987
1 0.765 134
1 0.445 890 
2 0.007 899?????????????? 
2 0.768 707??? 
2 0.789 865???? 
2 0.544? 678??????????? 
2? 0.987 889",sep="",header=TRUE)
library(plyr)
res <-?
ddply(transform(dat1,NewCol=Variable*Frequencies),.(Categories),summarize,
Avg=mean(NewCol/sum(Frequencies)))


A.K.




On Tuesday, December 24, 2013 10:43 AM, Nandini Jayakumar <nandini_dec6 at
hotmail.com> wrote:
Hello all

I have a table a sample of which is as follows:




??? 
??? 
??? 
??? 



??? 
??? 
??? 
??? 
??? ??? 
??? ??? ??? Categories

??? ??? 
??? ??? 
??? ??? ??? Variable (x)

??? ??? 
??? ??? 
??? ??? ??? Frequencies

??? ??? 
??? 
??? 
??? ??? 
??? ??? ??? 1

??? ??? ??? 1

??? ??? ??? 1

??? ??? ??? 1

??? ??? ??? 1

??? ??? 
??? ??? 
??? ??? ??? 0.009

??? ??? ??? 0.867

??? ??? ??? 0.567

??? ??? ??? 0.765

??? ??? ??? 0.445

??? ??? 
??? ??? 
??? ??? ??? 1003

??? ??? ??? 1200

??? ??? ??? 987

??? ??? ??? 134

??? ??? ??? 890

??? ??? 
??? 
??? 
??? ??? 
??? ??? ??? 2

??? ??? ??? 2

??? ??? ??? 2

??? ??? ??? 2

??? ??? ??? 2

??? ??? 
??? ??? 
??? ??? ??? 0.007

??? ??? ??? 0.768

??? ??? ??? 0.789

??? ??? ??? 0.544

??? ??? ??? 0.987

??? ??? 
??? ??? 
??? ??? ??? 899

??? ??? ??? 707

??? ??? ??? 865

??? ??? ??? 678

??? ??? ??? 889

??? ??? 
??? 
??? 
??? ??? 
??? ??? ??? 3

??? ??? ??? 3

??? ??? ??? 3

??? ??? ??? 3

??? ??? ??? 3

??? ??? 
??? ??? 
??? ??? ??? 0.898

??? ??? ??? 0.887

??? ??? ??? 0.560

??? ??? ??? 0.098

??? ??? ??? 0.987

??? ??? 
??? ??? 
??? ??? ??? 544

??? ??? ??? 677

??? ??? ??? 934

??? ??? ??? 467

??? ??? ??? 876

??? ??? 
??? 
??? 
??? ??? 
??? ??? ??? 40

??? ??? ??? 40

??? ??? ??? 40

??? ??? ??? 40

??? ??? ??? 40

??? ??? 
??? ??? 
??? ??? ??? 0.786

??? ??? ??? 0.342

??? ??? ??? 0.456

??? ??? ??? 0.987

??? ??? ??? 0.123

??? ??? 
??? ??? 
??? ??? ??? 843

??? ??? ??? 987

??? ??? ??? 675

??? ??? ??? 467

??? ??? ??? 223

??? ??? 
??? 



Basically I have 40 categories and each category has several hundred variables.
I want to calculate the average per category, that is variable *
frequency/Summation of frequencies. I want to do it for each category
separately. Since i have many categories i do not want to use the subset()
function 40 times. Is it possible to do it within a single data frame?

Really appreciate any help. Thank you.
??? ???  ??? ?  ??? ??? ? 
??? [[alternative HTML version deleted]]

______________________________________________
R-help at 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.