It seems from your questions that you are building something like a search engine. Maybe How to build a Search Engine. is of interest for you (a very good node IMHO), and maybe this article on perl.com.

If you insist on creating your index manually, here is what you could do: in the while loop create a list of all found words, and then iterate over all of them again: 

# assuming you stored all matches in @words
my %word_context;
for (1 .. $#words-1){
   push @{$word_context{$words[$_]}, [$words[$_ - 1], $words[$_ + 1]];
}

[download]

Though it might be better to store context and line number in the same data structure.

You also have to think about the first and the last word, which are special in that they don't have two words of context each. What do you want to do with them?

In reply to Re: Finding word either side of a word match by moritz
in thread Finding word either side of a word match by Quicksilver

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