Re^2: How To Read Hosts File Into a Hash

Thank you for your reply. I changed my code to the following.

#!/usr/bin/perl -w

use strict;

my $hostfile = "/etc/hosts";
my %hosts = ();


open FILE, "<", "$hostfile" || die "Cannot open $hostfile $!";
while (<FILE>) {
    next if /^\s*#/ ; # skip comments
    chomp;
    my ($key, $value) = split (" ", $_);
    $hosts{$key} = $value;
    }
close FILE;
[download]

The output is as follows.

Use of uninitialized value $key in hash element at hash.pl line 14, <F
+ILE> line 3.
Use of uninitialized value $key in hash element at hash.pl line 14, <F
+ILE> line 11.
[download]

Why do I get the "uninitialized error" for $key?

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Re^3: How To Read Hosts File Into a Hash by toolic (Bishop) on Sep 16, 2011 at 01:17 UTC
Why do I get the "uninitialized error" for $key? My guess is your input file has a blank line: `while (<FILE>) { next if /^\s*#/ ; # skip comments next unless /\S/; # skip blank lines chomp; my ($key, $value) = split; $hosts{$key} = $value; }` [download] See perlre	[reply] [d/l]
Re^3: How To Read Hosts File Into a Hash by keszler (Priest) on Sep 16, 2011 at 01:30 UTC
Your /etc/hosts file lines 3 and 11 have zero or more white space characters and nothing else. You should skip those: `while (<FILE>) { next if /\A\s\z/ ; # skip blank lines next if /^\s#/ ; # skip comments` [download] Or combine the regexes: `next if /\A\s*(?:#\|\z)/ ; skip comments and blank lines` [download]	[reply] [d/l] [select]