One thing that immediately jumped out at me is the question of why you're iterating over the keys of the hash just to determine if each of the individual hash keys match the word you're comparing from your input file. One of the express reasons for using a hash is so that you don't have to iterate over each element to find one.

If my task description were, "Read a text file, compare it to a banned word list, and then rewrite the text file, minus the banned words." I would probably do it something like this. ...note, this isn't a cut-and-paste solution for you, it's just an example from which you hopefully can derive a solution taylored to your needs... 

use strict;    # Please do this!
use warnings;  # And this!

# First, read from the <DATA> filehandle to grab the list
# of banned words.  map the banned words into hash-keys.
my %banned = map { chomp $_; $_=> undef } split /\s+/, <DATA>;
my $infile = "textfile.txt";
my $tmpfile = "outfile.tmp";

open my $in, "<$infile" or die "Cannot open $infile.\n$!";
open my $out, ">$tmpfile" or die "Cannot open temp output file.\n$!";

while ( my $inline = <$in> ) {
    chomp $inline;
    my $printline = "";
    foreach my $word ( split /\s+/, $inline ) {
        next if exists $banned{ lc $word };
        $printline .= $word;
    }
    print $out "$printline\n";
}
    
close $out;
close $in;
rename $tmpfile, $infile;

__DATA__
a at be for and to of in the as i it are is am on an you me b c d
e f g h j k l m n o p q r s t u v w x y z 0 1 2 3 4 5 6 7 8 9 10

[download]

I hope this helps... good luck.


Dave

In reply to Re: Removing common words by davido
in thread Removing common words by mkurtis

Title:
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, details, 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, summary, 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.