On 9/18/06, Palit, Nilanjan <[EMAIL PROTECTED]> wrote: > That works too (& I have used it as well), but I guess what I'm really > asking (hoping?) for is a Perl special variable, kinda like "$.", which > Perl auto-magically initializes & increments ...
As was pointed out, any desired magic variable *can* be built at some serious speed penalty compared to a built-in, but that doesn't seem like the right solution either. What is the *PURPOSE* of your push on newarray? Are you perhaps trying to push each item of oldarray into a sub array (row) of newarray? It sounds like you're trying to transpose a matrix. If so, and they're numeric, Perl modules for handling matrices may be helpful [http://search.cpan.org/search?query=Matrix+transpose] -- or PDL, the Perl Data Language [http://search.cpan.org/search?query=PDL], if they're big numeric matrices. If all the oldarrays are available in a outter array, as with a matrix to be transformed, but the elements are non-numeric, or it's small and you don't need all of a matrix lib, you can map over the outter array BUT doing it in new-array order to solve your problem efficiently, no index arithmetic - #! perl -l use strict; use warnings; my @newarray; my @outteroldarray= @{[ [1, 2, 3,], [4, 5, 6,], [7, 8, 9,], ]}; ## or [qw{a b c}], ... use Data::Dumper; print Dumper([EMAIL PROTECTED]); push @newarray, [map { shift @$_ } @outteroldarray ] while grep {scalar @$_} @outteroldarray; print Dumper [EMAIL PROTECTED]; ### EOF ### prints $old = [ [ 1, 2, 3 ], [ 4, 5, 6 ], [ 7, 8, 9 ] ]; $new = [ [ 1, 4, 7 ], [ 2, 5, 8 ], [ 3, 6, 9 ] ]; With ragged rows, e.g, 6, 4, 5 elements in 3 rows such as my @outteroldarray= @{[ [qw{a b c d e f}], [qw{g h i j}], [qw{k l m n o}], ]}; result in 6 rows of 3 elements, *internally* undef-padded as needed - ( [ 'a', 'g', 'k' ], [ 'b', 'h', 'l' ], [ 'c', 'i', 'm' ], [ 'd', 'j', 'n' ], [ 'e', undef, 'o' ], [ 'f', undef, undef ] ); which may not be what you want, or might be. Side note -- my @array=whatever(); for my $i (0..$#array) { doSomething($i, $array[$i], $array[f($i)] ); } is the way to get the index w/o using C-style for, when you really need index arithmetic. (If you don't need the $array[f($i)] term, you probably don't need to loop over both $i and @array together if you think map/grep enough.) Note : This 0..$#array would have been INefficient for big array back before for(0..$N) was optimized with a lazy list. And note: "for" and "foreach" keywords are interchangeable, either can take either set of parameters. -- Bill [EMAIL PROTECTED] [EMAIL PROTECTED] _______________________________________________ Boston-pm mailing list [email protected] http://mail.pm.org/mailman/listinfo/boston-pm
