Thanks.
On Tue, Sep 23, 2008 at 8:25 PM, John W. Krahn <[EMAIL PROTECTED]> wrote:
> Clemens Bieg wrote:
>
>> Hello,
>>
>> I am trying to iterate over all the lines of a file, each of which starts
>> with a line number, and isolate the line number and the corresponding
>> string
>> into one variable each, then have them printed into a separate file. Could
>> someone give me a clue on how to assign the line number match to the
>> variable so I can reuse it? Here is what I am trying (mainly by analogy
>> with
>> examples I found on the web and in books, but I am lacking the background
>> knowledge). At this point, all I am trying is to see if I can get the line
>> number into a variable, and print it out.
>>
>>
>> use strict;
>> use warnings;
>> my ($qfn_in_extract) = "extract/extract.txt";
>> my ($qfn_in_allnumbered) = "extract/allnumbered.txt";
>> my $dir = mkdir("final");
>>
>> open(my $fh_in_extract, '<', $qfn_in_extract)
>> or die("Unable to read file \"extract.txt\": $!\n");
>> open(my $fh_in_allnumbered, '<', $qfn_in_allnumbered)
>> or die("Unable to read file \"allnumbered.txt\": $!\n");
>> open(my $fh_out_final, '>', "final/final.txt")
>> or die("Unable to create file \"final.txt\": $!\n");
>>
>> my $id = '';
>>
>> while (<$fh_in_extract>) {
>>
>> if ($id = m/^\d+/) {
>> print $fh_out_final $id;
>> }
>> }
>>
>> # my $string = m/(?<=\d ).*?$/;
>> # print $fh_out_final $_;
>>
>>
>> This only gives me the return status. I have been playing with and without
>> the if statement, with and without the $id variable, with $_ instead of
>> $id,
>> and with =~ instead of =. But I do not see the light... I would
>> appreciate
>> if someone could point me in the right direction.
>>
>
> It looks like you need to capture the number using capturing parentheses:
>
> while ( <$fh_in_extract> ) {
>
> if ( /^(\d+)/ ) {
> print $fh_out_final $1;
> }
> }
>
>
> perldoc perlretut
> perldoc perlre
>
>
>
> John
> --
> Perl isn't a toolbox, but a small machine shop where you
> can special-order certain sorts of tools at low cost and
> in short order. -- Larry Wall
>
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>
>
