Hi Pietro, Depending on the actual structure you want in the output, you can use some of the functions in the apply family, particularly tapply, aggregate, or by. Something like :
R> tapply( d[["no_of_accidents" ]], d[[ "sex" ]], sum ) F M 34 83 R> aggregate( d["no_of_accidents" ], d[ "sex" ], sum ) sex no_of_accidents 1 F 34 2 M 83 R> by( d[["no_of_accidents" ]], d[[ "sex" ]], sum ) INDICES: F [1] 34 ------------------------------------------------------------ INDICES: M [1] 83 Cheers, Romain -- Mango Solutions data analysis that delivers R for finance training course :: 3 days :: London (27-29/02/2008) http://www.mango-solutions.com/services/rtraining/r_finance.html [EMAIL PROTECTED] wrote: > 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.
