On Fri, 30 May 2008, Duncan Murdoch wrote:
On 5/30/2008 1:55 PM, Prof Brian Ripley wrote:
Well, R has no unsigned quantities, so ultimately you can't actually do
this. But using what="int" and an appropriate 'size' (likely to be 8)
shold read the numbers, wrapping around very large ones to be negative.
(The usual trick of storing integers in numeric will lose accuracy, but
might be better than nothing.)
I think reading size 8 integers on 32 bit Windows returns signed 32 bit
integers, with values outside that range losing the high order bits, not just
accuracy. At least that's what I see when I write the numbers 1:10 out as 4
byte integers, and read them as 8 byte integers: I get 1 3 5 7 9.
Yes, that's true for even larger ones.
So to clarify: up to 2^31-1 should work, thereafter you will get the lower
32 bits and hence possibly a signed number.
Duncan Murdoch
On Thu, 29 May 2008, Sean Davis wrote:
Sorry for the simple question, but I am trying to read an "unsigned
long long" using the R readBin() function. Can someone point me in
the right direction, or am I better off using C for such things? The
file that I am reading will have been produced on the same machine
that is doing the reading.
Thanks,
Sean
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Brian D. Ripley, [EMAIL PROTECTED]
Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/
University of Oxford, Tel: +44 1865 272861 (self)
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