Ruby implementation of a K-Way Merge algorithm with support for streaming evaluation.
This is will be packaged as the k-way-merge rubygem, so you can just add the
dependency to your Gemfile or install the gem on your system:
gem install k-way-mergeTo require the library in your project:
require 'kway_merge'The library provides two primary features: the KWayMerge::Stream class
and the KWayMerge.combine convenience method.
The Stream class encapsulates the merge algorithm and provides a
lazy-evaluation interface for accessing the output stream.
The constructor takes an array of subcollections to merge (which are
assumed sorted individually) and a block describing how to get the sort
value for a given element. If no block is given, the element is assumed
to respond to <=> and will act as its own sort value.
The stream can then be queried with the empty? predicate and consumed
one element at a time with the shift method. You can skip(count)
over multiple elements, or collect(count) a handful of elements of the
stream. Getting all the remaining elements is as easy as collect(:all)
(you can also skip(:all), but that's kinda silly). If you don't want
to do your own looping, but collect and skip aren't general enough,
just iterate(count) or iterate(:all) with a custom block.
For when you don't need lazy evaluation and want the full result set.
Takes the same arguments as the KWayMerge::Stream constructor, but
immediately collects and returns all the results from the stream for
you.