Beefy Boxes and Bandwidth Generously Provided by pair Networks
There's more than one way to do things

comment on

( #3333=superdoc: print w/replies, xml ) Need Help??

So I'm the resident Perl Answer Guy at my orkplace (not that I'm the best Perl hacker here, but those better than I are either busy doing other stuff, like running the network, or just don't like answering questions). I got an interesting one the other day, and it's still bugging me.

My colleague had a 2d array simulating a textmode screen. 22 rows, 80 columns; however, he wanted to write to the "screen" first, then worry about over-long lines, so each row could have more than 80 chars in it. He had it set up like so:


The question was, how do you traverse this array row by row? The obvious answer,

foreach my $x (@vscr) { foreach my $y (@$x) { &do_stuff($y); } }
traverses the screen in the wrong order.

My first suggestion was to switch the order of x and y in the array; this isn't quite as intuitive for accesses, but makes the obvious traversal DTRT. But this bugged me: after all, TMTOWTDI, right? So I came up with this:

foreach my $row (0..21) { foreach my $col (@vscr) { &do_stuff($col[$row]); } }
(At this point, he has changed the order of x and y in the array, so this code never got used, which means it's untested and probably broken.)

This isn't so much worse than the obvious nested foreach approach, but it bugs me that the number of rows is hard coded. Is there a more general way to do this that's still fairly clean?

In reply to Fun with two-dimensional arrays by FoxtrotUniform

Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post; it's "PerlMonks-approved HTML":

  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.
  • Log In?

    What's my password?
    Create A New User
    and the web crawler heard nothing...

    How do I use this? | Other CB clients
    Other Users?
    Others about the Monastery: (3)
    As of 2019-05-20 05:17 GMT
    Find Nodes?
      Voting Booth?
      Do you enjoy 3D movies?

      Results (123 votes). Check out past polls.