Beefy Boxes and Bandwidth Generously Provided by pair Networks
good chemistry is complicated,
and a little bit messy -LW
 
PerlMonks  

Comment on

( #3333=superdoc: print w/ replies, xml ) Need Help??

All of the above answers seem to have problems with possible filehandle limits; personally I would read the entire file and convert it to a hash of arrays, and then write each array out to a file indicated by the array key. This has the advantage that only one file is open at any time. I will stick my neck out and say it will also be faster due to less file I/O

As a second comment, you should use something like Text::CSV to get the data, but if you want it quick and dirty there's a good argument for using split instead of a regex here.

Amount of Data: 300k rows = 64k per row = approx 19.6GB of data may cause problems, so maybe a compromise is to write the data when an array gets to a certain size.

The following (untested/debugged) shows the idea...it assumes you specify the file(s) you want to read from on the command line.

Update: Changed when it writes to file as a result of a davido comment

use constant ROW_LIMIT => 10000; sub writeData { my ($name, $data) = @_; open FH, ">>", "sample_$name"; print FH @$data; # may not be needed (auto close on sub end) close FH; } my %hash; my $ctr = 0; while (<>) { my @elems = split /|/; my $idx = $elem[1]; if (exists $hash{$idx}) { # save to existing array push @$hash{$idx}, $_; } else { # create new array $hash{$idx} = ( $_); }; # if we've got too much data, write it out if ($ctr++ >= ROW_LIMIT) { # write data to each file... foreach my $key (%hash) { writeData( $key, $hash{ $key}); delete $hash{$key}; } $ctr = 0; } } # write remaining data to each file... foreach my $key (%hash) { writeData( $key, $hash{ $key}); }
A Monk aims to give answers to those who have none, and to learn from those who know more.

In reply to Re: Split a file based on column by space_monk
in thread Split a file based on column by brad_nov

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post; it's "PerlMonks-approved HTML":



  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.
  • Log In?
    Username:
    Password:

    What's my password?
    Create A New User
    Chatterbox?
    and the web crawler heard nothing...

    How do I use this? | Other CB clients
    Other Users?
    Others examining the Monastery: (4)
    As of 2015-07-05 09:37 GMT
    Sections?
    Information?
    Find Nodes?
    Leftovers?
      Voting Booth?

      The top three priorities of my open tasks are (in descending order of likelihood to be worked on) ...









      Results (61 votes), past polls