On 12/22/2008 1:55 PM, murd...@stats.uwo.ca wrote:
I was wondering if copies were made when a component of a complex nested
list structure was extracted but not modified. I was happy that the
answer was no, but was surprised that copies weren't made even if the
extracted bit was modified:
> x <- list(a=list(b=numeric(1000000)))
> y <- x[[c(1,1)]]
> y[1] <- 3.14159
> x[[c(1,1)]][1]
[1] 3.14159
Unfortunately, this exists in today's release of 2.8.1. I should have
done this test last week!
The fix looks easy: The problem is that the NAMED status of the
component being extracted was miscalculated when using a vector index.
I'll commit a change after testing...
Duncan Murdoch
Duncan Murdoch
> sessionInfo()
R version 2.8.1 (2008-12-22)
i386-pc-mingw32
locale:
LC_COLLATE=English_United States.1252;LC_CTYPE=English_United
States.1252;LC_MONETARY=English_United
States.1252;LC_NUMERIC=C;LC_TIME=English_United States.1252
attached base packages:
[1] stats graphics grDevices utils datasets methods base
loaded via a namespace (and not attached):
[1] tools_2.8.1
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