refactored slice to avoid twice iteration

[leandromoh]

No description provided.

[viceroypenguin]

While there are two enumerable methods involved in the previous version, I don't see how it would have iterated the sequence twice - both Skip and Take are lazy, and neither will pull items unnecessarily. It would be good to update the tests for Slice to confirm this, though.

Furthermore, for non-list sequence, .Skip().Take() is already heavily optimized by the corelib. It turns into a single EnumerablePartition<TSource>() which handles both already. Take a look at the code here (Skip and Take are available in the same directory, and you can see that Skip creates the EnumerablePartition<> and Take calls EnumerablePartition<>.Take()). [note: since net6.0, Slice is actually an almost synonym for the bcl Take(IEnumerable<TSource> source, Range range) operator - Take(Range) is start..end and Slice(int, int) is start + count]

[codecov]

Codecov Report

Merging #1011 (d8fbc6b) into master (35fefdf) will decrease coverage by 0.01%.
The diff coverage is 91.66%.

❗ Current head d8fbc6b differs from pull request most recent head e221209. Consider uploading reports for the commit e221209 to get more accurate results

@@            Coverage Diff             @@
##           master    #1011      +/-   ##
==========================================
- Coverage   92.57%   92.57%   -0.01%     
==========================================
  Files         113      113              
  Lines        3422     3433      +11     
  Branches     1055     1060       +5     
==========================================
+ Hits         3168     3178      +10     
  Misses        191      191              
- Partials       63       64       +1     

Impacted Files	Coverage Δ
MoreLinq/Slice.cs	92.00% <91.66%> (-0.86%)	⬇️

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[atifaziz]

While there are two enumerable methods involved in the previous version, I don't see how it would have iterated the sequence twice - both Skip and Take are lazy, and neither will pull items unnecessarily.

@leandromoh I agree with @viceroypenguin here that there isn't any re-iteration going on here.

It would be good to update the tests for Slice to confirm this, though.

Yup, this should be done first and anyway. This was the idea behind PR #759. Either a commit against it or a separate one for just Slice would be welcome.

[atifaziz]

Closing this assuming it's unnecessary and abandoned.