A long time ago, i suggested a rather drawn out way to
transform a 1-D array into a 2-D array:
(jeffa) Re: Structure for nested html::template loops. It
uses autovivification to know which row to add the current
piece of data to. Upon showing this to one of my college
professors, he showed me a much simpler way to achieve the
same results in Python, using the
range
built-in function.
That function takes 3 args, the first two are the start and
stop points ... and if we stop right there then this
function is complete "word-candy", as the dot dot operator
already does this. But, the 3rd argument is the 'step',
which allows for some cool stuff:
use Data::Dumper;
my $step = 5;
my @array = ('a'..'z');
print Dumper [
map[ @array[$_..$_+$step-1] ],
range(0,$#array,$step)
];
This allows you to create a 2-D array from a 1-D array,
'folded' where ever you like. At the end, if there are no
more element to stuff in the last row, the correct amount
of 'undef' values will be pushed.
Now all we need is the ability to handle 'lazy lists' like
Python's
xrange. ;)
(and a big thanks to
merlyn for reviewing this and
improving it)
UPDATE: ack ... rob_au already posted something similar:
Stepping through an array. (he also points out Abigail-II's solution -
no grep needed!)
# usage: my @AoA = range($start,$stop[,$step]);
sub range {grep!(($_-$_[0])%($_[2]||1)),$_[0]..$_[1]}