Beefy Boxes and Bandwidth Generously Provided by pair Networks
P is for Practical

Comment on

( #3333=superdoc: print w/replies, xml ) Need Help??
Always put the for loop iterator variables as 'my' inside the for loop.
foreach my $region (@regions) { # something happening in the loop }
If you write
my $region foreach $region (@regions) { # something happening in the loop }
Perl silently declares a new lexical variable (also named $region) as the iterator variable. The new $region is scoped to the loop block and hides any variable $region from the outer scope. By explicitly putting the my in the foreach, you're reminding yourself of this behaviour. You're avoiding the misconception that the last value of $region will be available after the for loop (it won't, however you try to scope it). If you want that information you have to save it to an outside variable inside the loop
my $latest_region; foreach my $region (@regions) { $latest_region = $region; # something happening in the loop last if (some condition); } print "last region considered was $latest_region\n";
Most of this information lifted from "Non-Lexical Loop Iterators", 'Always declare a for loop iterator variable with my', in "Perl Best Practices", by Damian Conway

In reply to Re: Declaring a Variable [for BEGINNERS] by scooper
in thread Declaring a Variable [for BEGINNERS] by brusimm

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 all is quiet...

    How do I use this? | Other CB clients
    Other Users?
    Others about the Monastery: (5)
    As of 2018-03-17 07:14 GMT
    Find Nodes?
      Voting Booth?
      When I think of a mole I think of:

      Results (223 votes). Check out past polls.