Re^2: Joining Arrays? (perl6)

[eric256]

Perl6 provides a pretty handy way to do this. It has X which I beleive is pronounced "cross" so that you can do: (source)

use v6;

my @urls = ('http://www.something.com/blah.aspx?code=',
            'http://www.somethingelse.com/stuff.aspx?thing=');

my @ids = ('375035304','564564774','346464646');

my @combined = (@urls X @ids).map: {$^a ~ $^b};

.say for @combined;

Which outputs the following on Rakudo already:

http://www.something.com/blah.aspx?code=375035304
http://www.something.com/blah.aspx?code=564564774
http://www.something.com/blah.aspx?code=346464646
http://www.somethingelse.com/stuff.aspx?thing=375035304
http://www.somethingelse.com/stuff.aspx?thing=564564774
http://www.somethingelse.com/stuff.aspx?thing=346464646

The $^a and $^b in the map block tell it to take two elements at a time, while the X in the parenthesis tells it to cross join the two arrays. Very very handy for this kind of thing.

[TimToady]

Such cross-like operations are common enough that there is also a cross meta-operator in Perl 6 to trick an ordinary binary operator into doing it. So instead of saying:

    my @combined = (@urls X @ids).map: {$^a ~ $^b};

you can just say

    my @combined = @urls X~ @ids;

That is, just put X in front of the ordinary operator to make it a cross operator.

Update: changed old X~X form to new X~ form.

[nagalenoj]

Interesting. But, unfortunately I am using perl 5.8. Where can I read about the new arrivals in perl 6 version?

[eric256]

http://www.perlfoundation.org/perl6/index.cgi is a pretty good place to start reading about it.