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

I need to write some perl code that will compare line 1 with line 2, then compare line 2 with ilne 3 etc. I tried the following: 
while (my $timeOne = <INPUTFILE>)
{
 my $timeTwo =<INPUTFILE>;
 print OUTPUTFILE "timeOne: $timeOne";
 print OUTPUTFILE "timeTwo: $timeTwo";
 my $result = $timeTwo - $timeOne;
 print OUTPUTFILE "result = $result \n";
}

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But this will compare line 1 against line 2 and then line 3 against line 4.

Replies are listed 'Best First'.
Re: compare subsequent lines
by moritz (Cardinal) on Jul 14, 2009 at 15:35 UTC
    Please read Writeup Formatting Tips and update your post with proper markup. Thank you.

    What you can do something along these lines: 

    my $previous = <IN>;
while (<IN>) {
   # compare $_ and $previous here


   $previous = $_;
}

    [download]
[reply]
[d/l]
      Thanks Moritz that works great
[reply]

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