[R] R match - could be improved ?

[Michael Dewey]

Dear Jeremy

The NAs do not seem random to me as the gaps between successive NAs are 
either 3, 8 or 11.

Have you considered the possibility that the finite precision of real 
numbers in computers may be the issue here?

On 15/03/2015 11:04, Jeremy Clark wrote:
> ​Dear All,
>
> The following gives a very unpleasant experience with apparently random NAs
> - probably it's my bad formatting of the coding - but the effect is
> unexpected and if undetected can lead to considerable problems:
>
> myvector1 = NULL
>
> myvector3 = NULL
>
> myvector4 = NULL
>
> myvector5 = NULL
>
>
>
> myvector1 <- c(1:100)
>
>
>
>
>
> myvector3[[1]] <- seq(myvector1[1], myvector1["length"(myvector1)], by =
> 0.01)
>
> myvector4[[1]] <- seq(95, 100, by = 0.01)
>
>
>
> myvector5[[1]] <- match(myvector4[[1]], myvector3[[1]])
>
>
>
> myvector5
>
>
>
> ## A solution (but rather annoying):
>
>
>
> myvector5[[1]] <- match(as.list(myvector4[[1]]), as.list(myvector3[[1]]))
>
> myvector5
> ​
> Could anyone tell me why the NAs occur ??
>
> Many thanks.​
>
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-- 
Michael
http://www.dewey.myzen.co.uk