On Sep 18, 2012, at 5:10 PM, John Sorkin wrote:
> Window 7
> R 2.15
>
> I am writing a simulation which generates sample sized estimates from
> simulated data. When I run the function shown below,
> power.t.test(delta=14.02528,sd=1.945226,power=0.8,sig.level=0.05)
>
> I get an error message:
>
>> power.t.test(delta=14.02528,sd=1.945226,power=0.8,sig.level=0.05)
> Error in uniroot(function(n) eval(p.body) - power, c(2, 1e+07)) :
> f() values at end points not of opposite sign
>
> The fact that the function can not return a sample size is OK, however I need
> to trap the error and set the sample size equal to NA. How do I trap the
> error so that when the error occurs I can set sample size equal to NA?
?conditions #### has lots of fancy stuff
# But I use just plain old `try`
test=-10:10
sapply(test, function(x) if( "try-error" %in%
class( try( test[test[x:1]] ) ) ){
2}else{0} )
Error in test[x:1] : only 0's may be mixed with negative subscripts
Error in test[x:1] : only 0's may be mixed with negative subscripts
Error in test[x:1] : only 0's may be mixed with negative subscripts
Error in test[x:1] : only 0's may be mixed with negative subscripts
Error in test[x:1] : only 0's may be mixed with negative subscripts
Error in test[x:1] : only 0's may be mixed with negative subscripts
Error in test[x:1] : only 0's may be mixed with negative subscripts
Error in test[x:1] : only 0's may be mixed with negative subscripts
Error in test[x:1] : only 0's may be mixed with negative subscripts
Error in test[x:1] : only 0's may be mixed with negative subscripts
[1] 2 2 2 2 2 2 2 2 2 2 0 0 0 0 0 0 0 0 0 0 0
You still get the messages but the code runs.
--
David Winsemius, MD
Alameda, CA, USA
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