ddply() is what you are looking for. Here is an example http://www.inside-r.org/packages/cran/plyr/docs/ddply
Cheers, Rhydwyn Rhydwyn McGuire Senior Biostatistician | Health Statistics NSW Level 7, 73 Miller St, North Sydney 2060 Tel 02 9391 9781 | rm...@doh.health.nsw.gov.au www.health.nsw.gov.au -----Original Message----- From: R-help [mailto:r-help-boun...@r-project.org] On Behalf Of Val Sent: Tuesday, 13 October 2015 4:06 AM To: r-help@r-project.org Subject: [R] by group Hi all, Assume that I have the following data set : cntry state city Gender (1=F and 2=M) 1 1 1 1 1 1 1 2 1 1 1 1 1 1 2 2 1 2 2 2 1 2 3 2 1 2 3 1 I want to calculate the number of Females and Males, total (F+M) and percentage (F/M) by country, state and city. Here is the sample of the output file that I would like to have in a file. cntry state City Gender Cntry_F Cntry_M Cntry_total 100 (Cntry_F/Cntry_M) St_F st_M St_total 100*( St_F/ St_M) City_F City_M City_total 100*( City_F/ City_M) 1 1 1 1 3 4 7 75 2 2 4 50 1 1 3 33 1 1 1 2 3 4 7 75 2 2 4 50 1 1 3 33 1 1 1 1 3 4 7 75 2 2 4 50 1 1 3 33 1 1 2 2 3 4 7 75 2 2 4 50 2 0 2 100 1 2 2 2 3 4 7 75 2 1 3 67 2 0 2 100 1 2 3 2 3 4 7 75 2 1 3 67 1 1 2 50 1 2 3 1 3 4 7 75 2 1 3 67 1 1 2 50 Your help is highly appreciated in advance [[alternative HTML version deleted]] ______________________________________________ R-help@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. __________________________________________________________________________________________________________ This email has been scanned for the NSW Ministry of Health by the Websense Hosted Email Security System. Emails and attachments are monitored to ensure compliance with the NSW Ministry of health's Electronic Messaging Policy. __________________________________________________________________________________________________________ _______________________________________________________________________________________________________ Disclaimer: This message is intended for the addressee named and may contain confidential information. If you are not the intended recipient, please delete it and notify the sender. Views expressed in this message are those of the individual sender, and are not necessarily the views of the NSW Ministry of Health. _______________________________________________________________________________________________________ This email has been scanned for the NSW Ministry of Health by the Websense Hosted Email Security System. Emails and attachments are monitored to ensure compliance with the NSW Ministry of Health's Electronic Messaging Policy. ______________________________________________ R-help@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.
