Since R evaluates arguments 'greedily', it will evaluate the return()
component (and return from the function) without even seeing the second
component.
This example might clarify things:
f <- function(x) { return(x)/stop("bad!") }
> f(1)
[1] 1
Also possibly useful:
lobstr::ast(return(OR^2+6*OR+1)/(OR*se^2))
█─`/`
├─█─return
│ └─█─`+`
│ ├─█─`+`
│ │ ├─█─`^`
│ │ │ ├─OR
│ │ │ └─2
│ │ └─█─`*`
│ │ ├─6
│ │ └─OR
│ └─1
└─█─`(`
└─█─`*`
├─OR
└─█─`^`
├─se
└─2
On 2025-04-30 9:06 a.m., Duncan Murdoch wrote:
`return` is a function. I am away from my computer right now so I can't
check, but I would expect you could create your own function named that.
Other languages have `return` statements instead.
On Wed, Apr 30, 2025, 02:17 Ralf Goertz via R-help <r-help@r-project.org>
wrote:
I made a stupid error when programming a function. I used
return(OR^2+6*OR+1)/(OR*se^2)
Being parenthesis blind it took me half an hour to find the reason for
the nonsensical results I got. I should have written
return((OR^2+6*OR+1)/(OR*se^2))
Having said that why is the first variant (which returns the value of
the numerator only) not a syntax error? I would have expected R to
report something like
Error: unexpected '/' in "return(OR^2+6*OR+1)/"
If this is not an error what is its purpose?
______________________________________________
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
https://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 https://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
--
Dr. Benjamin Bolker
Professor, Mathematics & Statistics and Biology, McMaster University
Director, School of Computational Science and Engineering
> E-mail is sent at my convenience; I don't expect replies outside of
working hours.
______________________________________________
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 https://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
