I don't think it is avoidable... ifelse cannot figure out which elements will exist in the second and third arguments until they are evaluated, so it cannot make use of the TRUE/FALSE information until both possible output vectors have been evaluated, which is a performance hit and yields warnings or errors.
You, on the other hand, can figure that out and use input validation to limit which inputs get fed into the warning- or error- producing algorithm and put the results into a final result vector using indexed assignment as Dr Fox suggested. On October 8, 2021 5:21:44 AM PDT, Ravi Varadhan via R-help <r-help@r-project.org> wrote: >Thank you to Bert, Sarah, and John. I did consider suppressing warnings, but I >felt that there must be a more principled approach. While John's solution is >what I would prefer, I cannot help but wonder why `ifelse' was not constructed >to avoid this behavior. > >Thanks & Best regards, >Ravi >________________________________ >From: John Fox <j...@mcmaster.ca> >Sent: Thursday, October 7, 2021 2:00 PM >To: Ravi Varadhan <ravi.varad...@jhu.edu> >Cc: R-Help <r-help@r-project.org> >Subject: Re: [R] How to use ifelse without invoking warnings > > > External Email - Use Caution > > > >Dear Ravi, > >It's already been suggested that you could disable warnings, but that's >risky in case there's a warning that you didn't anticipate. Here's a >different approach: > > > kk <- k[k >= -1 & k <= n] > > ans <- numeric(length(k)) > > ans[k > n] <- 1 > > ans[k >= -1 & k <= n] <- pbeta(p, kk + 1, n - kk, lower.tail=FALSE) > > ans >[1] 0.000000000 0.006821826 0.254991551 1.000000000 > >BTW, I don't think that you mentioned that p = 0.3, but that seems >apparent from the output you showed. > >I hope this helps, > John > >-- >John Fox, Professor Emeritus >McMaster University >Hamilton, Ontario, Canada >web: >https://nam02.safelinks.protection.outlook.com/?url=https%3A%2F%2Fsocialsciences.mcmaster.ca%2Fjfox%2F&data=04%7C01%7Cravi.varadhan%40jhu.edu%7Cfd882e7c4f4349db34e108d989bc6a9f%7C9fa4f438b1e6473b803f86f8aedf0dec%7C0%7C0%7C637692265160038474%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C2000&sdata=Q33yXm36BwEVKUWO72CWFpSUx7gcEEXhM3qFi7n78ZM%3D&reserved=0 > >On 2021-10-07 12:29 p.m., Ravi Varadhan via R-help wrote: >> Hi, >> I would like to execute the following vectorized calculation: >> >> ans <- ifelse (k >= -1 & k <= n, pbeta(p, k+1, n-k, lower.tail = FALSE), >> ifelse (k < -1, 0, 1) ) >> >> For example: >> >> >>> k <- c(-1.2,-0.5, 1.5, 10.4) >>> n <- 10 >>> ans <- ifelse (k >= -1 & k <= n, pbeta(p,k+1,n-k,lower.tail=FALSE), ifelse >>> (k < -1, 0, 1) ) >> Warning message: >> In pbeta(p, k + 1, n - k, lower.tail = FALSE) : NaNs produced >>> print(ans) >> [1] 0.000000000 0.006821826 0.254991551 1.000000000 >> >> The answer is correct. However, I would like to eliminate the annoying >> warnings. Is there a better way to do this? >> >> Thank you, >> Ravi >> >> >> [[alternative HTML version deleted]] >> >> ______________________________________________ >> R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see >> https://nam02.safelinks.protection.outlook.com/?url=https%3A%2F%2Fstat.ethz.ch%2Fmailman%2Flistinfo%2Fr-help&data=04%7C01%7Cravi.varadhan%40jhu.edu%7Cfd882e7c4f4349db34e108d989bc6a9f%7C9fa4f438b1e6473b803f86f8aedf0dec%7C0%7C0%7C637692265160048428%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C2000&sdata=FXX%2B4zNT0JHBnDFO5dXBDQ484oQF1EK5%2Fa0dG9P%2F4k4%3D&reserved=0 >> PLEASE do read the posting guide >> https://nam02.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.r-project.org%2Fposting-guide.html&data=04%7C01%7Cravi.varadhan%40jhu.edu%7Cfd882e7c4f4349db34e108d989bc6a9f%7C9fa4f438b1e6473b803f86f8aedf0dec%7C0%7C0%7C637692265160048428%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C2000&sdata=ss2ohzJIY6qj0eAexk4yVzTzbjXxK5VZNors0GpsbA0%3D&reserved=0 >> 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. -- Sent from my phone. Please excuse my brevity. ______________________________________________ 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.