Hi,
In article <[EMAIL PROTECTED]>, John W. Krahn wrote:
> Dan Muey wrote:
[...]
>> I currently have to do this via the command line:
>>
>> my @unique = qx(sort -u file.txt);
>>
>> To remove duplicat elines from file.txt.
>>
>> What would be the best way to do the same thign with perl instead of
>> calling an external program?
>>
>> I can always assign each element of the array to a hash I suppose,
>> that way there could only be one key that is whatever element.
>>
>> I was hoping for a one liner though.
>
> Ok, but it may be a bit long. :-)
>
> my $file = 'file.txt';
>
> my @unique = do {
> open my $fh, '<', $file or die "Cannot open $file: $!";
> my %seen;
> grep !$seen{$_}++, <$fh>
> };
How much different is:
my $file = 'file.txt';
{
open my $fh, '<', $file or die "Cannot open $file: $!";
my %seen;
my @unique = grep {!$seen{$_}++} <$fh>;
}
(Or, what does 'do' do here that I, too, should do 'do'?)
Hmmmm, looking at my block, maybe the answer is "it places @unique outside
of the block so that it is still accessible (but keeps our throwaway
variables 'local')"?
BTW, doesn't 'sort -u' also sort the list?
-K
--
Kevin Pfeiffer
International University Bremen
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