[R] Assign references

From: <Seeliger.Curt_at_epamail.epa.gov>
Date: Sat 08 Oct 2005 - 05:17:57 EST


I've run into trouble while writing functions that I hope will create and modify a dataframe or two. To that end I've written a toy function that simply sets a couple of variables (well, tries but fails). Searching the archives, Thomas Lumley recently explained the <<- operator, showing that it was necessary for x and y to exist prior to the function call, but I haven't the faintest why this isn't working:

> myFunk<-function(a,b,foo,bar) {foo<<-a+b; bar<<-a*b;}
> x<-0; y<-0;
> myFunk(4,5,x,y)
> x<-0; y<-0;
> myFunk(4,5,x,y)
> x

[1] 0
> y

[1] 0

What (no doubt simple) reason is there for x and y not changing?

Thank you,

Curt Seeliger, Data Ranger
CSC, EPA/WED contractor

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Received on Sat Oct 08 05:29:54 2005

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