Issue #14697 has been updated by mrkn (Kenta Murata).


I'm supposing that this new notation of Range#step is mostly used for slicing numerical arrays like Numo::NArray.
This usecase is very similar to Python's slice notation used for slicing numpy's arrays.

With this new notation, `ary[::2]` in python can be written as `ary[(0...)%2]` in Ruby 2.6.
Slicing an array with a stepped range is often used in data analysis.
For example, if daru supports this new notation, we can pick up even rows in a dataframe `df` by `df.row[(0..)%2]`.

----------------------------------------
Feature #14697: Introducing Range#% as an alias to Range#step
https://bugs.ruby-lang.org/issues/14697#change-71613

* Author: mrkn (Kenta Murata)
* Status: Open
* Priority: Normal
* Assignee: matz (Yukihiro Matsumoto)
* Target version: 
----------------------------------------
In #13904, `Enumerator::ArithmeticSequence` has been accepted for the representation of a range with step value.
And in #12912, a new syntax of endless range `(1..)` has been accepted.

Combining these new features, we can write an endless step range like `(1..).step(2)` in Ruby 2.6.
It can be used for array slicing like python's `1::2`.

If `Range#%` is introduced as an alias to `Range#step`, we can write a step range like `(1..)%2`.
This notation is already introduced numo-narray.




-- 
https://bugs.ruby-lang.org/

Unsubscribe: <mailto:ruby-core-request / ruby-lang.org?subject=unsubscribe>
<http://lists.ruby-lang.org/cgi-bin/mailman/options/ruby-core>