As a beginner, I made all of these mistakes and then some. Thank you chromatic for this excelent node, and dominus for the Red Flag papers. While forcing myself to rewrite a script to have them all  use strict I came up with the following solutions which may be of benefit to others like me (for most of you this is way too trivial, but this is the voice of a beginner).

To access a number of files in a loop construct, this was my initial attempt:

for ($results = 2; $results <34; $results++) { my $file="current$results.res"; open (TALLYRESULTS, ">$file") or die ("cant open results f +ile"); .... }

A common mistake, apparently, which turned out to be easy to avoid:

for ($results = 2; $results <34; $results++) { my $file="current".$presence.".res"; .... }

Another (double!) 'Red Flag' situation was this:

@tree1=@samples[0..2]; ... (another 10 of those) @tree12=@samples[33..35]; for ($z = 1; $z <= 12; $z++) { $arrayname="tree$z"; foreach $patch(@$arrayname) { ... do something }

and solving it taught me a thing or two about hashes:

my %trees = (1 => "@samples[0..2]", ... (another 10 of these) 12 => "@samples[33..35]", ); while ((my $tree, my $samples) = each (%trees) ){ my @patches = split (/ */, $samples); foreach $patch(@patches) { ... do something }

My script now runs under strict, and I'm proud of it ;-)

In reply to Re: Common Beginner Mistakes by Elias
in thread Common Beginner Mistakes by chromatic

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.