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.rsoft at gmail.com>
To: r-help at 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]]
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