[R] R2.11.1 seq.int difference between by and length.out

[Alexander]

Berend Hasselman wrote
> 
> On 10-04-2012, at 15:54, Alexander wrote:
> 
>> I am working under R2.11.1 Windows and I was wondering why there is a
>> difference between
>> 
>> seq.int(0,1,by=0.1)[4]-0.3
>> seq.int(0,1,length.out=11)[4]-0.3 
>> 
>> there is also the fact that
>> 
>> seq(0,1,by=0.1)[4]-0.3
>> seq(0,1,length.out=11)[4]-0.3 
>> 
>> but I think this can be explained by floating precision... 
> 
> 
> R FAQ:  http://cran.r-project.org/doc/FAQ/R-FAQ.html
> 
> 7.31 Why doesn't R think these numbers are equal?
> 
This explains what the difference, but the problem for 

seq(2)*seq(2)==2

is not the same as

0.3+0.1-0.4==0

There must be a difference in the calculation for by and length.out in
seq.int otherwise there wouldn't be a difference in seq.int

seq.int(0,1,length.out=11)[4]-seq.int(0,1,by=0.1)[4]

I am more interested in the generation of the sequence...


Berend Hasselman wrote
> 
> Berend
> 
> 
> 
> 
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