in reply to Re: Can this script be Optimized?
in thread Can this script be Optimized?

"As far as I know, all of the functions provided by that module are implemented in C, so you also get a performance bonus."

Indeed, they are. List::Util also happens to make very efficient use of Perl's API (e.g. using multicall), allowing its functions to perform at speeds approaching Perl's built-in list operators (grep, map, sort).

"See also: List::MoreUtils"

This is also written in C (and also makes use of multicall), but has a fallback Perl implementation allowing it to be installed on machines lacking a C compiler.

If a function exists in both List::Util and List::MoreUtils (and because recent List::Util releases have been adding new functions, the overlap between them is growing), then prefer the List::Util one because it will be guaranteed to be implemented in C.

use Moops; class Cow :rw { has name => (default => 'Ermintrude') }; say Cow->new->name

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Re^3: Can this script be Optimized?
by kcott (Archbishop) on May 01, 2014 at 09:03 UTC

    Thanks for the feedback.

    I had seen the C and pure-Perl implementation information in List::MoreUtils [from CPAN]; however, the List::Util [from perldoc.perl.org] documentation made no mention of this: hence the "As far as I know" qualifier.

    I was a little surprised when you mentioned there was an overlap between these two modules as I wasn't aware of this. I did a little investigation and found:

    http://perldoc.perl.org/List/Util.html

    Indicates Perl v5.18.2 and only shows these functions: first max maxstr min minstr reduce shuffle sum. It does show any, all, et al, which currently exist in List::MoreUtils, as suggested additions which haven't been included. (I couldn't find any mention of a module version number.)

    http://search.cpan.org/~pevans/Scalar-List-Utils-1.38/lib/List/Util.pm

    This does show any, all, et al as being included.

    $ perldoc List::Util

    This appears to be the same doco as the CPAN version. Checking my versions: List::Util 1.38 and Perl 5.18.1

    I have, up until now, used the perldoc.perl.org documentation for all builtin modules. It's clear that this is out-of-date for List::Util (i.e. it's not the POD that ships with 5.18.2); unfortunately, this leave me wondering what other parts of its doco aren't up-to-date.

    -- Ken

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      Beginning with List::Util 1.28, List::Util added a great deal of new functions. However, the version of List::Util included in the Perl 5.18.x releases is 1.27. (And perldoc.perl.org only includes documentation for modules bundled with stable releases of Perl.)

      The new functions are:

      • Added in 1.28: pairgrep, pairmap, pairs, pairkeys, and pairvalues.
      • Added in 1.30: pairfirst.
      • Added in 1.33: any, all, none, and notall. ← these are the ones which overlap with List::MoreUtils
      • Added in 1.35: product.

      I don't know what version of List::Util will be bundled with Perl 5.20.0, but it's likely to be at least 1.38. Of course, you don't need to wait for Perl 5.20.0 to use these functions; List::Util 1.38 is already on CPAN.

      use Moops; class Cow :rw { has name => (default => 'Ermintrude') }; say Cow->new->name
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        Thanks for tracking down all that info. It would appear my concerns about perldoc.perl.org not being up-to-date are unfounded.

        "Of course, you don't need to wait for Perl 5.20.0 to use these functions; List::Util 1.38 is already on CPAN."

        Actually, I don't have to wait or, indeed, do anything at all. :-)

        As stated above:

        "... my versions: List::Util 1.38 and Perl 5.18.1"

        I didn't (deliberately) install List::Util 1.38, so it must have been a dependency of some other module I installed via cpan.

        -- Ken

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