http://qs321.pair.com?node_id=762634

JurgyMan has asked for the wisdom of the Perl Monks concerning the following question:

I'm comparing two files and deducing Add/Del/Changes from the comparison. I had been using a hash map to do it, but run out of ram with 1.7G input files!! So now am trying to read each line in a loop... This doesnt appear to be working for me: my($ln) = <CURR>; All examples I see have that in a while loop (and work)... Full Code is here: http://jurgy.net/code/

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Re: read from two files at once?
by samtregar (Abbot) on May 07, 2009 at 15:29 UTC
    The problem with:

    my ($in) = <CURR>;

    Is that it puts <CURR> in list context. That causes it read all the lines in your file and then put the first one in $in! Instead you want:

    my $in = <CURR>;

    Which will read just one line. Reading from two files should work with something like: 

      open FILE1, "<", "file1.txt" or die $!;
  open FILE2, "<", "file1.txt" or die $!;
  while (!eof(FILE1) and !eof(FILE2)) {
    my $line1 = <FILE1>;
    my $line2 = <FILE2>;
    # ...
  }

    [download]

    -sam

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Re: read from two files at once?
by eff_i_g (Curate) on May 07, 2009 at 16:49 UTC
    Is diff, sdiff, or Text::Diff out of the question? Just curious.
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