Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!usc!elroy.jpl.nasa.gov!jpl-devvax!lwall
From: lwall@jpl-devvax.jpl.nasa.gov (Larry Wall)
Newsgroups: comp.lang.perl
Subject: Re: Is Perl's sort stable?
Keywords: sort, perl
Message-ID: <1991Apr9.044100.22563@jpl-devvax.jpl.nasa.gov>
Date: 9 Apr 91 04:41:00 GMT
References: <1991Apr3.224701.9318@eng.umd.edu>
Reply-To: lwall@jpl-devvax.JPL.NASA.GOV (Larry Wall)
Organization: Jet Propulsion Laboratory, Pasadena, CA
Lines: 12

In article <1991Apr3.224701.9318@eng.umd.edu> stripes@eng.umd.edu (Joshua Osborne) writes:
: Is Perl's sort stable?  By that I mean if I have a list of 6 char long scalers,
: and ask sort to sort by the last 3 letters and then again by the first 3 will
: I have the same effect as if I had sorted by all six in the same place?  (I am
: asking because I have data sorted by date given in a messy date format, and
: I want to sort by user name but preserve the secondary sorting by date...  I
: could solve the problem without assuming Perl's sort is stable, but why go to
: all that extra work if Perl does do a stable sort?).

No, it relies on C's qsort, which is not stable.  Sorry...

Larry