Comparison To Other Languages
Some other languages provide a convenient interface to the same optimization as the Schwartzian transform:
- In Python 2.4 and above, both the sorted function and the in-place list.sort method take a key= parameter that allows the user to provide a "key function" (like foo in the examples above). In Python 3 and above, use of the key function is the only way to specify a custom sort order (the previously-supported comparator argument was removed). Before Python 2.4, developers would use the lisp-originated Decorate-Sort-Undecorate (DSU) idiom, usually by wrapping the objects in a (sortkey, object) tuple.
- In Ruby 1.8.6 and above, the Enumerable abstract class (which includes Arrays) contains a sort_by method which allows you to specify the "key function" (like foo in the examples above) as a code block.
- In D 2 and above, the schwartzSort function is available. It might require less temporary data and be faster than the Perl idiom or the decorate-sort-undecorate idiom present in Python and Lisp. This is because sorting is done in-place and only minimal extra data (one array of transformed elements) is created.
- Racket's core
sortfunction accepts a#:keykeyword argument with a function that extracts a key, and an additional#:cache-keys?requests that the resulting values are cached during sorting. For example, a convenient way to shuffle a list is(sort l < #:key (λ (_) (random)) #:cache-keys? #t).
Read more about this topic: Schwartzian Transform
Famous quotes containing the words comparison to, comparison and/or languages:
“In comparison to the French Revolution, the American Revolution has come to seem a parochial and rather dull event. This, despite the fact that the American Revolution was successful—realizing the purposes of the revolutionaries and establishing a durable political regime—while the French Revolution was a resounding failure, devouring its own children and leading to an imperial despotism, followed by an eventual restoration of the monarchy.”
—Irving Kristol (b. 1920)
“When we reflect on our past sentiments and affections, our thought is a faithful mirror, and copies its objects truly; but the colours which it employs are faint and dull, in comparison of those in which our original perceptions were clothed.”
—David Hume (1711–1776)
“People in places many of us never heard of, whose names we can’t pronounce or even spell, are speaking up for themselves. They speak in languages we once classified as “exotic” but whose mastery is now essential for our diplomats and businessmen. But what they say is very much the same the world over. They want a decent standard of living. They want human dignity and a voice in their own futures. They want their children to grow up strong and healthy and free.”
—Hubert H. Humphrey (1911–1978)