As others have replied, the customary way is to use the seq() function that takes additional arguments besides a from= and a to= such as by= to specify the step size and two others sometimes handy of length.out= and along.with=
In your case seq(from=1.5, to=3.5, by=0.5) works as well as the shorter positional version of seq(1.5, 3.5, 0.5) But as others have noted, certain calculations with floating point arithmetic in pretty much any language can be imprecise in the final bits. I doubt it matters for you but there are ways to do a comparison that allows for a little leeway and still tests equal. The suggestion others have made is a good choice too, especially when you know exactly what you need in advance and can adjust: > seq(1.5, 3.5, 0.5) [1] 1.5 2.0 2.5 3.0 3.5 > seq(3, 7) / 2 [1] 1.5 2.0 2.5 3.0 3.5 > 0.5*(3:7) [1] 1.5 2.0 2.5 3.0 3.5 If you do this often and for larger vectors and efficiency matters, consider using seq.int() in the latter cases as it is much faster when working on just integers. -----Original Message----- From: R-help <r-help-boun...@r-project.org> On Behalf Of Catherine Walt Sent: Friday, October 29, 2021 3:06 AM To: R mailing list <r-help@r-project.org> Subject: [R] customize the step value dear members, Sorry I am newbie on R. as we saw below: > 1.5:3.5 [1] 1.5 2.5 3.5 How can I make the step to 0.5? I want the result: 1.5 2.0 2.5 3.0 3.5 Thanks. Cathy ______________________________________________ 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. ______________________________________________ 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.