A = read.table("clipboard", header=TRUE) > A sex age region no_of_accidents 1 F young north 10 2 F young south 12 3 F old north 5 4 F old south 7 5 M young north 24 6 M young south 30 7 M old north 12 8 M old south 17
sum(A$no_of_accidents[which( A$sex=="F")]) should give you the required sum. You have to remember that sex, age and region are Factors with their respective levels and no_of_accidents is a numeric vector. Do str( A) to see their type. Hope that helps. Mama ----- Mama Attiglah, PhD Advanced Research Center Quantitative Research Analyst State Street Bank +44(0)20 7698 6290 (Direct Line) +44 (0)207 004 2968 (Direct Fax) Please visit our Web site at www.ssga.com -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED] Sent: 29 January 2008 12:05 To: r-help@r-project.org Subject: [R] pivot table in R Hello, I'm struggling with an elementary problem with R. I have a simple data frame such as this one giving the number of accidents subdivided by sex, age and region. sex age region no_of_accidents F young north 10 F young south 12 F old north 5 F old south 7 M young north 24 M young south 30 M old north 12 M old south 17 and I would like to build a pivot table, e.g. obtaining the sum of the number of accidents for each sex: sex age region no_of_accidents F (any) (any) 34 M (any) (any) 83 but I can't seem to obtain this result simply in R, except by embarking in complicated "for" loops. I have checked the documentation on such functions as "table()" and the documentation on "An introduction to R" but couldn't solve the problem. Could you please help me with this? Cheers Pete PLEASE CONSIDER THE ENVIRONMENT BEFORE PRINTING THIS E-MAIL For Aon's standard conditions associated with this e-mail please visit http://www.aon.com/uk/en/email-footer/aon-limited.jsp Aon Limited Registered Office: 8 Devonshire Square, London EC2M 4PL Registered in London No. 210725 . VAT Registration No. 480 8401 48 Aon Limited is authorised and regulated by the Financial Services Authority in respect of insurance mediation activities only. [[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.