simple range question

[Edwin van Leeuwen via Digitalmars-d-learn]

On Friday, 8 April 2016 at 18:27:59 UTC, Laeeth Isharc wrote:
> suppose I have a forward or random access range.  what's the 
> best way to compare each element with the element 4 elements 
> prior to that element?  I could map each element to a tuple of 
> the element and the element 4 bars previously and do it that 
> way.  any neater way ?

I'd do it like this, but I guess that is what you mean with 
mapping it to a tuple:

zip( r, r[4..$] ).map!((t) => t[0] == t[1]);