Steve Bertrand wrote:
> Thomas Bätzler wrote:
>> Bob Williams <n...@spam.barrowhillfarm.org.uk> asked:
>>> 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.
>>
>>> ---Code---
>>> #!/usr/bin/perl
>>> use warnings;
>>> #use strict;
>>
>> use strict; # unless you know what you're doing.
>>
>>> #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: $!";
>>
>> Better:
>>
>> open( my $bfh_file, '<', '/home/bob/tmp/md5music' ) or die ...
>>
>>> @bhffile = <BHF_FILE>;
>>> close (BHF_FILE);
>>>
>>> for (my $i = 0; $i <= $#bhffile; $i++){
>>> $bhffile[$i] =~ m/(\s.+) ( .+)/;
>>> push @ukchecksum, $1[$i];
>>> push @uktrackname, $2[$i];
>>> }
>>
>> If your track names are unique, you're much better off using an
>> associative array ("hash") for your data.
>>
>> It also makes comparison with track names and checksums from a second
>> list much easier:
>>
>> my %uktrackchecksum;
>>
>> while( my $line = <$bhf_file> ){
>> my( $track, $checksum ) = split /\s+/, $line;
>> $uktrackchecksum{ $track } = $checksum;
>> }
>
> That split will not do what the OP wants AFAICT. It will take the first
> two items that are separated by whitespace, and throw away the rest.
>
> Following the 'do something with one line at a time as opposed to eating
> the file all at once' (the regex isn't all that pretty, but its early ;)
>
> ...and left in the hash, as I agree that it's more effective, however,
> it may be hard to work with later with such random and 'stringy'
> information:
>
> #!/usr/bin/perl
>
> use warnings;
> use strict;
>
> my %music_store;
>
> while ( my $entry = <DATA> ) {
>
> $entry =~ m{ (.*?) \s+ (.*) \n }xms;
>
> my $checksum = $1;
> my $song = $2;
>
> # we can work with the data while looping
> # over it
>
> print "Checksum: $checksum\n";
> print "Rest: $song\n";
>
> # and stash it away so we can use it later
> # ...each song (key) has a checksum
>
> $music_store{ $song } = $checksum;
>
> }
>
> # print them out
>
> while ( my ( $song, $checksum ) = each %music_store ) {
>
> print "$song has checksum: $checksum\n";
> }
>
> __DATA__
> 60196093f7a180d1f2d5fb47ded646be artists/Abdullah
> Ibrahim/Various/abdullah ibrahim - Black Lightning.mp3
Thanks. There's a lot in your version for a newbie to learn, but
unfortunately, it still gives the same error :(
19:14 barrowhillfarm:~> ~/Documents/scripts/perl/music_md5_compare3.pl
Use of uninitialized value $checksum in concatenation (.) or string at
/home/bob/Documents/scripts/perl/music_md5_compare3.pl line 18.
Checksum:
Use of uninitialized value $song in concatenation (.) or string at
/home/bob/Documents/scripts/perl/music_md5_compare3.pl line 19.
Rest:
Use of uninitialized value $song in hash element at
/home/bob/Documents/scripts/perl/music_md5_compare3.pl line 24.
Use of uninitialized value $checksum in concatenation (.) or string at
/home/bob/Documents/scripts/perl/music_md5_compare3.pl line 32.
has checksum:
Bob
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