Hi Ken,
The help page for ?"for" says that:
The index seq in a for loop is evaluated at the start of the loop; changing
it subsequently does not affect the loop. The variable var has the same type
as seq, and is read-only: assigning to it does not alter seq.
So you cannot do what you want to do with a for loop. But you could do what
you want with a while loop:
i <- 0
while(i < 20) {
i <- i + 1
cat(i, "\n")
if(i %% 5 == 0) i <- i + 2
}
-Christos
> -----Original Message-----
> From: r-help-boun...@r-project.org
> [mailto:r-help-boun...@r-project.org] On Behalf Of Lo, Ken
> Sent: Wednesday, March 04, 2009 3:53 PM
> To: r-help@r-project.org
> Subject: [R] FW: flow control
>
> Hi all,
>
> I need a little help with flow control in R. What I'd like
> to do is to advance a for loop by changing its counter.
> However, what seems obvious to me does not yield the proper
> results. An example of my problem is
>
>
> for (i in seq(1, some_number, some_increment)){
> <some stuff>
> if (some_condition == T) i <- i + 2; #want to advance
> the loop by 2 }
>
> Whenever the counter goes to the next step, the next item in
> the original sequence seq(1, some_number, some_increment)
> replaces the counter value. Is there a way for me to do this?
>
> Best,
>
> Ken
>
>
>
> ______________________________________________
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> and provide commented, minimal, self-contained, reproducible code.
>
>
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