Re: Open in for loop/array structure

I would try running it like this:

#!/usr/local/bin/perl
use warnings;
use strict;

my @FN = map "out-02-$_.txt", '00' .. '18', 20 .. 28, 30 .. 38;

for my $filename ( @FN ) {
    print "$filename\n";

    open my $FILE, '<', $filename or die "Can't open $filename: $!";
    open my $OUT, '>', "ND_$filename" or die "Can't open ND_$filename:
+ $!";

    my ( @BU, @MA1, @MA2 );
    while ( my $line = <$FILE> ) {
        if ( $line =~ /K-INF,LEAK \(B2/ ) {
            push @BU, ( split ' ', $line )[ 14 ];
            }
        elsif ( $line =~ /0 EID:      93237/ ) {
            push @MA1, join ' ', ( split ' ', <$FILE> )[ 3 .. 11 ];
            }
        elsif ( $line =~ /0 EID:      95241/ ) {
            push @MA2, join ' ', ( split ' ', <$FILE> )[ 3 .. 9 ];
            }
        }

    for my $i ( 0 .. 57 ) {
        print $OUT join( ' ', $BU[ $i ] || '', $MA1[ $i ] || '', $MA2[
+ $i ] || '' ), "\n";
        }
    }
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Re^2: Open in for loop/array structure by igotlongestname (Acolyte) on Jun 03, 2008 at 17:58 UTC
jw, Thanks for the suggestion, I'll put it in and give it a shot see how it works. It's pretty much guaranteed to be "better" than what I've got, in terms of concise-ness and "correctness" or whatever. Thanks for taking the time to help me out, it's really appreciated! ~Jack Update ... I put it in and ran, and it ran beautifully. One question, if you can give me a pointer. In filling the @FN array, you use the map command and the $_ character, I think I understand that alright, but why did you have to put the first chunk of numbers in single quotes (i.e. '00 .. '18'), but not the rest of them? Is either convention acceptable or is there something specific here? Also, in the for loop, is it automatic convention that if an array with a scalar name before it (in this case calling $filename in the loop, with the looping parameter being @FN) is accessed, the length of the loop is the length of the array, and the scalar is automatically updated to be each member of the array, starting at 0 and going to the last array point? Does that make sense or is it too wordy? Just trying to understand exactly how in the for loop, the code knows to use each name in the array. Thanks again! ~Jack	[reply]
Re^3: Open in for loop/array structure by jwkrahn (Abbot) on Jun 03, 2008 at 20:52 UTC
why did you have to put the first chunk of numbers in single quotes (i.e. '00' .. '18'), but not the rest of them? I used the quotes because without them perl would remove the leading zeros. how in the for loop, the code knows to use each name in the array. That is the way that for/foreach loops work.	[reply]