[R] sapply and loop

[Liaw, Andy]

Without seeing what myfunction is, it's almost impossible to tell.

In addition to system.time(), you might want to profile your code.  e.g.,

Rprof()
zz <- sapply(ma, myfunction)
Rprof(NULL)
summaryRprof()

HTH,
Andy

> From: Zhen Pang
> 
> Dear all,
> 
> I am doing 200 times simulation. For each time, I generate a 
> matrix and 
> define some function on this matrix to get a 6 dimension vector as my 
> results.
> 
> As the loop should be slow, I generate 200 matrice first, and 
> save them into 
> a list named ma,
> then I define zz<-sapply(ma, myfunction)
> 
> To my surprise, It almost costs me the same time to get my 
> results if I 
> directly use a loop from 1 to 200. Is it common? Can I 
> improve any further?
> 
> Ps, how to count the exact time to finish my code?
> 
> Thanks.
> 
> Zhen
> 
> ______________________________________________
> R-help at stat.math.ethz.ch mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide! 
> http://www.R-project.org/posting-guide.html
> 
>