Dear Ding, It seems that you are looking for the ifelse() function. Clear use of pmax() and pmin() reduces the number of if statements.
m1 <- c(12, 23, 22, 23) m2 <- c(23, 23, 3, 5) Ravg <- ifelse( pmax(m1, m2) == 23, pmin(m1, m2), (m1 + m2) / 2 ) Best regards, ir. Thierry Onkelinx Statisticus / Statistician Vlaamse Overheid / Government of Flanders INSTITUUT VOOR NATUUR- EN BOSONDERZOEK / RESEARCH INSTITUTE FOR NATURE AND FOREST Team Biometrie & Kwaliteitszorg / Team Biometrics & Quality Assurance thierry.onkel...@inbo.be Havenlaan 88 bus 73, 1000 Brussel www.inbo.be /////////////////////////////////////////////////////////////////////////////////////////// To call in the statistician after the experiment is done may be no more than asking him to perform a post-mortem examination: he may be able to say what the experiment died of. ~ Sir Ronald Aylmer Fisher The plural of anecdote is not data. ~ Roger Brinner The combination of some data and an aching desire for an answer does not ensure that a reasonable answer can be extracted from a given body of data. ~ John Tukey /////////////////////////////////////////////////////////////////////////////////////////// <https://www.inbo.be> Op di 7 apr. 2020 om 20:35 schreef Yuan Chun Ding <ycd...@coh.org>: > Hi R users, > > > I want to create a new variable, Ravg, in data frame tem2 based on values > of two other variables m1 and m2. > > the condition: > > if m1 = 23 and m2 =23 then Ravg =23; > else if m1 != 23 and m2=23 then Ravg =m1; > else if m1 =23 and m2 !=23 then Ravg=m2; > else Ravg=average of m1 and m2; > > the Ravg variable should be same as m3 variable in the following small > example. > > my R code did not generate errors but not generate a new variable. > > Ravg <- "rare_allele" > tem2 <-data.frame(m1=c(12, 23, 22, 23), m2=c(23, 23, 3, 5), m3 =c(12, > 23, 12.5, 5)) > for (r in 1:nrow(tem2)) { > if (tem2$m1[r] ==23 & tem2$m2[r] ==23) { > tem2[[Ravg]][r] ==23} else if(tem2$m1[r] ==23 & tem2$m2[r] !=23){ > tem2[[Ravg]][r] ==tem2$m2[r]} else if (tem2$m1[r] !=23 & tem2$m2[r] > ==23) { > tem2[[Ravg]][r] ==tem2$m1[r]} else { > tem2[[Ravg]][r] == mean(tem2$m1[r] + tem2$m2[r])} > } > > Thank you, > > Ding > > ---------------------------------------------------------------------- > ------------------------------------------------------------ > -SECURITY/CONFIDENTIALITY WARNING- > > This message and any attachments are intended solely for the individual or > entity to which they are addressed. This communication may contain > information that is privileged, confidential, or exempt from disclosure > under applicable law (e.g., personal health information, research data, > financial information). Because this e-mail has been sent without > encryption, individuals other than the intended recipient may be able to > view the information, forward it to others or tamper with the information > without the knowledge or consent of the sender. If you are not the intended > recipient, or the employee or person responsible for delivering the message > to the intended recipient, any dissemination, distribution or copying of > the communication is strictly prohibited. If you received the communication > in error, please notify the sender immediately by replying to this message > and deleting the message and any accompanying files from your system. If, > due to the security risks, you do not wish to receive further > communications via e-mail, please reply to this message and inform the > sender that you do not wish to receive further e-mail from the sender. > (LCP301) > > ______________________________________________ > 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. > [[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.
