Hello everyone. 
I need some help to understand when number precision in R is set. For this 
please consider the following example


 for (i in c(2:length(final))){
    sizex <- c(sizex,(final[i]-final[i-1],digits=2))) # round is used to remove 
values that are too small like e-17.
    print(round(final[i]-final[i-1],digits=2))
  }

final[2]-final[1] return something like 4.440892e-16, which means that these two 
numbers are the same. They are two but as they were derived from a different 
process they are not the same for precision.

Also the line print(round(final[2]-final[1]),digits=2) returns 0 which is 
correct

When the above loop stops executing inside sizex variable I find the value 
4.440892e-16 which I was not expecting.  As you can see from small code snippet 
before setting the value in the sizex I try to round it. The print gives the 
right value but for some reason it seems that inside the loop the precision in 
sizex is changed.

Can you please help me clarify that?

Best Regards
Alex


      
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