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Re: Perl - write data from hashes

by CountZero (Bishop)
on Oct 13, 2013 at 17:25 UTC ( #1058090=note: print w/replies, xml ) Need Help??

in reply to Perl - write data from hashes

This part of your code is rather strange:
if (exists($r1{$key})){ $r1{$key} += $f[02]; } else { $r1{$key} += $f[02]; }
You do exactly the same whether or not the key already exists in the hash. Therefore you can replace this simply by:
$r1{$key} += $f[02];


A program should be light and agile, its subroutines connected like a string of pearls. The spirit and intent of the program should be retained throughout. There should be neither too little or too much, neither needless loops nor useless variables, neither lack of structure nor overwhelming rigidity." - The Tao of Programming, 4.1 - Geoffrey James

My blog: Imperial Deltronics

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Re^2: Perl - write data from hashes
by marinersk (Priest) on Oct 14, 2013 at 05:51 UTC

    In older versions of Perl, I encountered the issue where attempting to add a value to an undefined hash element would generate a warning.

    I see under my modern version of Perl, this is not an issue:

    #!/usr/bin/perl -w use strict; my $TEST_KEY = 'abc'; my $TEST_VAL = 5; my %TestHash = (); { print "-----[ Addition to undef ]---------------\n"; %TestHash = (); $TestHash{$TEST_KEY} += $TEST_VAL; print "-----[ Addition testing for undef ]------\n"; %TestHash = (); if (defined $TestHash{$TEST_KEY}) { $TestHash{$TEST_KEY} += $TEST_VAL; } else { $TestHash{$TEST_KEY} = $TEST_VAL; } } exit; __END__ C:\Steve\Dev\PerlMonks\P-2013-10-13@2339-HashUndef> -----[ Addition to undef ]--------------- -----[ Addition testing for undef ]------

    I think -- not 100% sure, but I think -- I am happy about this.

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