Thanks, that problem looks very similar to mine. try is a nice hack. I was
thinking t.test would be intelligent enough to display NA if there are any
problems than to terminated.

On 2/12/08, Richard Pearson <richard.pearson@postgrad.manchester.ac.uk>
wrote:
>
> Do you mean to deal with the situation where you're doing many t-tests
> in a loop? If so there was a post very recently on this list about this:
>
> https://stat.ethz.ch/pipermail/r-help/2008-February/153254.html
>
> Richard.
>
>
> Ng Stanley wrote:
> > Thanks. Someone please help to make t.test go through all the data and
> not
> > to be disrupted by the two problems.
> >
> > On 2/12/08, Petr PIKAL <petr.pikal@precheza.cz> wrote:
> >
> >> Hi
> >>
> >> r-help-bounces@r-project.org napsal dne 12.02.2008 09:09:23:
> >>
> >>
> >>> Hi,
> >>>
> >>> First problem:
> >>>
> >>>> test <- matrix(c(1,1,2,1), 2,2)
> >>>> apply(test, 1, function(x) { t.test(x) $p.value })
> >>>>
> >>> Error in t.test.default(x) : data are essentially constant
> >>>
> >> make your data not constant
> >>
> >>
> >>> Second problem:
> >>>
> >>>> test <- matrix(c(1,0,NA,1), 2,2)
> >>>> apply(test, 1, function(x) { t.test(x) $p.value })
> >>>>
> >>> Error in t.test.default(x) : not enough 'x' observations
> >>>
> >> increase number of observations
> >>
> >>
> >>
> >>> How to make t-test ignores this errors ?
> >>>
> >> Well, the procedure is complaining that you do not give it correct
> data.
> >> You shall be gratefull for a great software which prevent you from
> making
> >> silly things as try to compute t.test when data have zero variantion or
> >> number of observations is 1.
> >>
> >> Regards
> >> Petr
> >>
> >>
> >>>    [[alternative HTML version deleted]]
> >>>
> >>> ______________________________________________
> >>> R-help@r-project.org mailing list
> >>> 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.
> >>>
> >>
> >
> >       [[alternative HTML version deleted]]
> >
> > ______________________________________________
> > R-help@r-project.org mailing list
> > 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.
> >
> >
>

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