File length ??

[Anonymous Monk]

Hello, Is there an easier way to determine the length of a data file. The file I'm reading in has blank lines, that I DON'T want in my array.

This is my current code:

while(<DATA>){

    # Populate the data array
    if ($_ ne ""){
        push @data, $_;
    }
}
close DATA;

my $length = @data;
print "LENGTH: $length\n";

My check for NULL doesn't seem to work....
Any suggestions?

[Aristotle]

I don't because there's still an end of line marker. You could check for that explicitly:

while(<DATA>){
    next if $_ eq $/;
    push @data, $_;
}

# shorter:

$_ ne $/ and push @data, $_ while <DATA>;

See perldoc perlvar about $/. Or you could remove the linebreaks:

while(<DATA>){
    chomp;
    next if $_ eq '';
    push @data, $_;
}

See perldoc -f chomp.

Makeshifts last the longest.

[Moonie]

Take a look at this node - for removing null strings from your array - Removing empty string elements from an Array. That'll help with getting the accurate length.

[dws]

Please take a moment before you post to make sure you're asking the question you indend to have answered. "File size" and "number of non-blank lines in a file" are two very different things.

The quick way to determine a file size (if you're interested) is by using -s or stat(). Consult the docs.

[charnos]

Are you trying to determine the number of lines in the data file after taking out blank lines? Also, what's blank? Does blank include spaces? My suggestion would be as such:

@data = grep { $_ !~ /^\s*$/ } @a;
my $length = scalar @data;

That is assuming that blank lines may or may not include spaces. If you know that they will not, you could save yourself a good deal of time (especially for large files) by simply testing $_ ne "" in the grep.

[thor]

perl does a wonderful job of pattern matching. Here's what I've got:

while(<DATA>){

    # Populate the data array
    if ($_ !~ /^\s*$/){
        push @data, $_;
    }
}

This gets rid of lines that have only whitespace. If you want truly blank lines take the \s* out of the regex.

thor