Hi, I am not sure I understand it correctly. dat1<-read.table(text=" customer.name product cost John Toothpaste 30 Mike Toothpaste 45 Peter Toothpaste 40 ",sep="",header=TRUE,stringsAsFactors=FALSE) dat1$no.of.orders<- sqrt((dat1$cost-3.40)/1.20) dat1 # customer.name product cost no.of.orders #1 John Toothpaste 30 4.708149 #2 Mike Toothpaste 45 5.887841 #3 Peter Toothpaste 40 5.522681 A.K.
----- Original Message ----- From: Prakasit Singkateera <asltjoey.rs...@gmail.com> To: r-help@r-project.org Cc: Sent: Sunday, February 17, 2013 8:10 AM Subject: [R] How to do a backward calculation for each record in a dataset Hi Experts, I have a dataset of 3 columns: customer.name product cost John Toothpaste 30 Mike Toothpaste 45 Peter Toothpaste 40 And I have a function of cost whereby cost = 3.40 + (1.20 * no.of.orders^2) I want to do a backward calculation for each records (each customer) to find his no.of.orders and create a new column named "no.of.orders" in that dataset but I don't know how to do. Please help me. Thank you everyone, Prakasit [[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. ______________________________________________ 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.
