http://www.perlmonks.org?node_id=891222


in reply to Re^10: incrementing already existing file
in thread incrementing already existing file

In this section of your code: 
while ( <MYFILE> ) {
    chomp;
    my( $label, $index, $value ) = ( split /\s+/ )[3, 5, -1];
    
    $a_vals[ $index ] = $value;
    $b_vals[ $index ] = $value;
}

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You need to check the value of $index to get the values for type 'A' into @a_vals, similarly for the 'B' values. The way you have it, you only get 'B' values because they are the last ones in MYFILE, and you are putting the same things into both @a_vals and @b_vals. Since the 'B' values come in last, they overwrite the corresponding 'A' values in @a_vals. You can use the same kind of if/elsif/else logic as in your other loop to fix this(but see comments below on ways to improve that).

Now for this part of the loop over NEWF: 

if ($label eq "A"){
$fields[-2] = $a_vals[ $index ]
    
   }
   if ($label eq "B"){
$fields[-2] = $b_vals[ $index ]

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You should use if / elsif / else here: 

if ($label eq "A") {
    $fields[-2] = $a_vals[ $index ]
}
elsif ($label eq "B") {
    $fields[-2] = $b_vals[ $index ]
}
else {
    print "OOPS!  bad label\n";  # complain if something is fishy
}

[download]

You're getting there.

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Re^12: incrementing already existing file
by wanttoprogram (Novice) on Mar 03, 2011 at 16:50 UTC
    Perfect. It worked. Thank you for your clean answers and time.
[reply]
      My pleasure. I'll offer one other piece of advice. roboticus already said pretty much the same thing here, but it bears repeating. Get into the habit of keeping nested blocks of code properly indented; each new block should be indented more than the block that contains it. When you see that you have levels of indentation (i.e., many levels of nesting), it's usually a clue that you need to think again about what you are doing. As you get more experience, this will become automatic, but you can always use a program called perltidy to help you keep things neat.

      Keep at it. You will get the hang of it. I just takes practice.

[reply]

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