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Re^2: using hashes

by R56 (Sexton)
on Sep 26, 2013 at 15:08 UTC ( #1055854=note: print w/replies, xml ) Need Help??

in reply to Re: using hashes
in thread iterating hash keys?

Something like this: (assuming @lines as the array that has the input)

for my $line (@lines) { while(my ($find, $replace) = each %ids) { s/$find/$replace/g } }

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Re^3: using hashes
by kennethk (Abbot) on Sep 26, 2013 at 15:47 UTC
    This should work, and is clear to read. While it is not optimally efficient, efficiency shouldn't be your concern at this stage. If this isn't working, you need to post more information about your actual script. Posting real input, expected output, and actual code (all wrapped in <code> tags) will greatly facilitate the debugging. As discussed in How do I post a question effectively?.

    #11929 First ask yourself `How would I do this without a computer?' Then have the computer do it the same way.

      It's only partially working, because it's not matching exactly the 'pattern-key'.

      Supposing I have both banana AND bananas, being two different names and banana having an ID of 25, he's translating like:



      I'm guessing the [] exact match operator doesn't work on these cases?

        That is a trickier proposition. If you know your words are separated by word boundaries, you can solve your issue with the \b assertion:
        That will require that either side of your key must correspond to the start or finish of the line, or to the pattern \w\W or \W\w.

        If you can't use word boundaries to delimit, you could try your keys in descending key length.

        for my $line (@lines) { for my $find(sort {length($b) <=> length($a)} keys %ids) { $line =~ s/$find/$ids{$find}/g; } }

        This still has some potential for key overlap, but we'd really need to see you real data to design the correct regex for it. There are a number of ways to cut this up, the choosing the 'right' answer depends strongly on actual input.

        #11929 First ask yourself `How would I do this without a computer?' Then have the computer do it the same way.

Re^3: using hashes
by arrestee (Novice) on Sep 26, 2013 at 15:58 UTC

    For an effective solution to your problem, see BrowserUK's comment below. As to why the code you've shown doesn't work, it's probably because you're storing each line of your file/array in $line, but doing your substitution against $_. Try this: $line =~ s/$find/$replace/g.

      Thanks arrestee, that suggestion did some of the trick, but still having the 'exact match' problem that I replied to Kenneth on top...

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