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Re: Common Beginner Mistakes

by Elias (Pilgrim)
on Jan 27, 2001 at 16:15 UTC ( #54746=note: print w/replies, xml ) Need Help??

in reply to Common Beginner Mistakes

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 ;-)

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