Bob Williams wrote:
Hi,
Hello,
I am trying to split the lines in a file into two halves (at the first
space) each half going into an array. The code I have written is below. The
print command is there to test that things worked correctly, but it only
gives an error for each instance of the print command...
Use of uninitialized value within @uktrackname in print at
/home/bob/Documents/scripts/perl/music_md5_compare.pl line 22 (#1)
---Code---
#!/usr/bin/perl
use warnings;
#use strict;
You shouldn't comment out that line. Strictures can help you find
mistakes in your code.
#use diagnostics;
# perl script to compare two files of md5 checksums
#+and extract the lines which differ
open (BHF_FILE, "</home/bob/tmp/md5music")
or die "Could not open md5music: $!";
@bhffile = <BHF_FILE>;
Why are you reading the entire file into memory? You only need to
process one line at a time.
close (BHF_FILE);
for (my $i = 0; $i <= $#bhffile; $i++){
That is usually written as:
for my $i ( 0 .. $#bhffile ) {
$bhffile[$i] =~ m/(\s.+) ( .+)/;
What exactly does your data look like? Your regular expression says:
match a single WHITESPACE character followed by one or more of ANY
character followed by a single SPACE character followed by another
single SPACE character followed by one or more of ANY character.
push @ukchecksum, $1[$i];
push @uktrackname, $2[$i];
You do not define the arrays @1 or @2 anywhere so why are you trying to
use them here? If you want the contents of the capturing parentheses
from the regular expression then they are in the variables $1 and $2 but
you should only use them if you verify that the regular expression
matched successfully. You would probably be better off using an array
of arrays or a hash instead of two separate arrays.
}
print @ukchecksum[0]; # Won't print - uninitialized value ???
print @uktrackname[0]; # Won't print - uninitialized value !!!
Why are you using an array slice to access a scalar value? Perl should
have warned you about that.
John
--
The programmer is fighting against the two most
destructive forces in the universe: entropy and
human stupidity. -- Damian Conway
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