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Re^3: extract only smallest numbers

by grep (Monsignor)
on Jul 21, 2007 at 21:38 UTC ( #628034=note: print w/ replies, xml ) Need Help??

in reply to Re^2: extract only smallest numbers
in thread extract only smallest numbers


Couple of things first.

  • Use strict and warnings
  • Check to see if your open succeeds
  • Use split not a regex when you want to split
  • Indent your code - It makes reading the code easier on you and us
So your code should look something like (untested):
use strict; use warnings; open FILE, $my_file or die "Can't open $my_file\n"; my %hash; while (<FILE>) { my ($name, $code) = split(/\t/); }
Now you have some of the problems fixed. Now you need to test what's in the hash and $code.

One thing to remember is, that if you have not assigned a value to the hash for that key you'll get undef returned, which evaluates to 0 numerically. Since you are looking for the lowest number you'll want avoid the undef. So check the value from your hash with defined first. If you see that it is not defined, then you know to assign the value of $code whatever it is.

# Still untested if ( !defined( $hash{$name} ) ) { $hash{$name} = $code; }
If you have a value defined then check to see whats larger
# Still untested if ( !defined( $hash{$name} ) or $code < $hash{$name} ) { $hash{$name} = $code; }
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