Hi Paolo, You say you have monthly observations of two variables, say Sales and Customers.
Then, what you should have is something like this: Year Month Sales Customer 2012 Jan ss_12.1 cc_12.1 2012 Feb ss_12.2 cc_12.2 ... ... ... ... 2013 Jan ss_13.1 cc_13.1 2013 Feb ss_13.2 cc_13.2 ... ... ... ... where ss_YY.M and cc_ YY.M are numerical values (the total sales and number of customers for year YY and month M, respectively). For example, Year Month Sales Customer 2012 Jan 100 25 2012 Feb 120 30 ... ... ... ... If this is the case, and you have the data in a data frame (say df), all you need to do to create a new column in your data frame with the average revenue is: > df$Av_revenue <- df$Sales/ df$Customer You can omit df$ from the instruction above if you want to create the object Av_revenue but not include it in the data frame. I am not getting it right, would you please send us the first three or four lines of your data? Regards, José -----Original Message----- From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] On Behalf Of Paolo Donatelli Sent: 09 January 2013 16:03 To: r-help@r-project.org Subject: [R] Basic loop programming Hi all, newbie question: I am trying to set up a very simple loop without succeeding. Let's say I have monthly observation of two variables for a year - Sales_2012_01, Sales_2012_02, Sales_2012_03, .... (total sales for jan 2012,feb 2012, etc.) - Customers_2012_01, Customers_2012_02, .... (total number of customers for jan 2012, etc.) and I want to create new monthly variables in order to compute revenues per customers: Av_revenue_2012_01 = Sales_2012_01 / Customers_2012_01 Av_revenue_2012_02 = Sales_2012_02 / Customers_2012_02 ... how can I proceed? In other programming language I used just to write something like for (i in list("01","02, ..., "12") { Av_revenue_2012_'i' = Sales_2012_'i' / Customers_2012_'i' } but in R it seems not to work like that. Further, and correct me if I am wrong, I cannot use simple (i in 1:12) since I have a 0 digit in front of the single-digit months. thanks in advance for your help ______________________________________________ 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. Wrap Up and Run 10k is back! Also, new for 2013 – 2km intergenerational walks at selected venues. So recruit a buddy, dust off the trainers and beat the winter blues by signing up now: http://www.ageuk.org.uk/10k Milton Keynes | Oxford | Sheffield | Crystal Palace | Exeter | Harewood House, Leeds | Tatton Park, Cheshire | Southampton | Coventry Age UK Improving later life http://www.ageuk.org.uk ------------------------------- Age UK is a registered charity and company limited by guarantee, (registered charity number 1128267, registered company number 6825798). Registered office: Tavis House, 1-6 Tavistock Square, London WC1H 9NA. For the purposes of promoting Age UK Insurance, Age UK is an Appointed Representative of Age UK Enterprises Limited, Age UK is an Introducer Appointed Representative of JLT Benefit Solutions Limited and Simplyhealth Access for the purposes of introducing potential annuity and health cash plans customers respectively. Age UK Enterprises Limited, JLT Benefit Solutions Limited and Simplyhealth Access are all authorised and regulated by the Financial Services Authority. ------------------------------ This email and any files transmitted with it are confidential and intended solely for the use of the individual or entity to whom they are addressed. If you receive a message in error, please advise the sender and delete immediately. Except where this email is sent in the usual course of our business, any opinions expressed in this email are those of the author and do not necessarily reflect the opinions of Age UK or its subsidiaries and associated companies. Age UK monitors all e-mail transmissions passing through its network and may block or modify mails which are deemed to be unsuitable. Age Concern England (charity number 261794) and Help the Aged (charity number 272786) and their trading and other associated companies merged on 1st April 2009. Together they have formed the Age UK Group, dedicated to improving the lives of people in later life. The three national Age Concerns in Scotland, Northern Ireland and Wales have also merged with Help the Aged in these nations to form three registered charities: Age Scotland, Age NI, Age Cymru. ______________________________________________ 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.
