Is there some functions like zip and fold in Perl?

问题

I want to use some function such as "zip", "fold" and "map" in perl. (Just like in Haskell.) I found map and it works well. Then, is there zip and fold? Thank you very much.

回答1:

I've implemented many of those functions (and even Haskell-like lazy ones) in my module List::Gen

use List::Gen qw(zip reduce);

my @list = zip [1 .. 4], ['a' .. 'd'];

my $str = reduce {$a . $b} @list;

say $str; # 1a2b3c4d

Or using the glob function to build the ranges:

use List::Gen 'glob';

say <1 .. 4>->zip(<a .. d>)->reduce('$a.$b'); # 1a2b3c4d

Using ->reduce('.') or ->reduce(sub {$a . $b}) also works.

Or if you are golfing:

say <[.]>->(<1..4>|<a..d>);

Or for the Haskell versions, see List::Gen::Haskell

回答2:

The List::Util library includes reduce(), which does essentially what fold does.

List::MoreUtils contains a zip() function.

Neither is built-in, mostly because Perl is not a functional programming language.

回答3:

If you're interested in using functional programming concepts in Perl, then I highly recommend that you read Higher Order Perl.

回答4:

Modules that provide functional programming tools:

Perl's map and grep
List::Util
List::MoreUtils
List::Gen and List::Gen::Haskell (including lazy lists)
Algorithm::Loops

You might also be interested in the (now free to download) book Higher Order Perl.

来源：https://stackoverflow.com/questions/9115666/is-there-some-functions-like-zip-and-fold-in-perl

标签

perl

map

zip

fold