[R] How can I avoid nested 'for' loops or quicken the process?

Charles C. Berry cberry at tajo.ucsd.edu
Mon Dec 22 21:33:55 CET 2008

On Mon, 22 Dec 2008, Brigid Mooney wrote:

> Hi All,
> I'm still pretty new to using R - and I was hoping I might be able to get
> some advice as to how to use 'apply' or a similar function instead of using
> nested for loops.

Unfortunately, you have given nothing that is reproducible.

The details of MyFunction and the exact structure of the list objects are 

Check out the _Posting Guide_ for hints on how to formulate a question 
that will elecit an answer that helps you.



> Right now I have a script which uses nested for loops similar to this:
> i <- 1
> for(a in Alpha) { for (b in Beta) { for (c in Gamma) { for (d in Delta) {
> for (e in Epsilon)
>  {
>       Output[i] <- MyFunction(X, Y, a, b, c, d, e)
>        i <- i+1
>  }}}}}
> Where Output[i] is a data frame, X and Y are data frames, and Alpha, Beta,
> Gamma, Delta, and Epsilon are all lists, some of which are numeric, some
> logical (TRUE/FALSE).
> Any advice on how to implement some sort of solution that might be quicker
> than these nested 'for' loops would be greatly appreciated.
> Thanks!
> 	[[alternative HTML version deleted]]
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Charles C. Berry                            (858) 534-2098
                                             Dept of Family/Preventive Medicine
E mailto:cberry at tajo.ucsd.edu	            UC San Diego
http://famprevmed.ucsd.edu/faculty/cberry/  La Jolla, San Diego 92093-0901

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