[Rd] Reading an "unsigned long long" using R readBin()

[Duncan Murdoch]

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.

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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>