Your two options do different things. One searches a given document and the other modifies the given document.

For your first option, that's one of the better ways to do it.

For your second option, I would do 

while (my ($word, $replacement) = each %{$termHash})
{
    $document =~ s/$word/$replacement/g;
}

[download]
That uses much less memory. for will build a list in memory. each will iterate through that list without building it in memory first.

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Being unknowing, is not the same as being stupid.
Expressing a contrary opinion, whether to the individual or the group, is more often a sign of deeper thought than of cantankerous belligerence.
Do not mistake your goals as the only goals; your opinion as the only opinion; your confidence as correctness. Saying you know better is not the same as explaining you know better.

In reply to Re: Hash versus substitutation efficiency? by dragonchild
in thread Hash versus substitutation efficiency? by bwelch

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