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Top Forums Shell Programming and Scripting Incredibly inefficient cat | grep script Post 302913041 by Cludgie on Wednesday 13th of August 2014 12:50:06 PM
Old 08-13-2014
Incredibly inefficient cat | grep script

Hi there,

I have 2 files that I am trying to work on.

File 1 contains a reference list of unique subscriber numbers ( 7 million entries in total)

File 2 contains a list of the subscriber numbers and their tariff (15 million entries in total). This file is in the production system and hasn't had old subscribers removed for some time so more than half of the entries need removed.

I created the following couple of lines to try to obtain the active 7 million subscriber numbers and tariffs from the behemoth 15 million list

Code:
 cat accurate_list.csv | while read ref
> do
> grep $ref production_list.csv >> new_msisdn_list.csv
> done

While this is actually working, it's only producing around 20 entries per second, which will take days to complete.

I'm afraid I'm a complete noob and can't come up with anything more inventive. I'm sure awk/sed/perl or probably any other number of languages would be perfect for something like this.

Anyway any suggestions are gratefully received.

Thanks
Cludgie
 

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Text::CSV::Encoded::Coder::EncodeGuess(3pm)		User Contributed Perl Documentation	       Text::CSV::Encoded::Coder::EncodeGuess(3pm)

NAME
Text::CSV::Encoded::Coder::EncodeGuess - Text::CSV::Encoded coder class using Encode::Guess SYNOPSIS
use Text::CSV::Encoded coder_class => 'Text::CSV::Encoded::Coder::EncodeGuess'; use Spreadsheet::ParseExcel; my $csv = Text::CSV::Encoded->new(); $csv->encoding( ['ucs2', 'ascii'] ); # guessing ucs2 or ascii? $csv->encoding_to_combine('shiftjis'); my $excel = Spreadsheet::ParseExcel::Workbook->Parse( $file ); my $sheet = $excel->{Worksheet}->[0]; for my $row ( $sheet->{MinRow} .. $sheet->{MaxRow} ) { my @fields; for my $col ( $sheet->{MinCol} .. $sheet->{MaxCol} ) { my $cell = $sheet->{Cells}[$row][$col]; push @fields, $cell->{Val}; } $csv->combine( @fields ) or die; print $csv->string, " "; } DESCRIPTION
This module is inherited from Text::CSV::Encoded::Coder::Encode. USE
Except for 2 attributes, same as Text::CSV::Encoded::Coder::Encode. encoding_in $csv = $csv->encoding_in( $encoding_list_ref ); The accessor to an encoding for pre-parsing CSV strings. If no encoding is given, returns current $encoding, otherwise the object itself. $encoding_list_ref = $csv->encoding_in() When you pass a list reference, it might guess the encoding from the given list. $csv->encoding_in( ['shiftjis', 'euc-jp', 'iso-20022-jp'] ); If it cannot guess the encoding, the first encoding of the list is used. encoding $csv = $csv->encoding( $encoding_list_ref ); $encoding_list_ref = $csv->encoding(); You can pass a list reference to this attribute only: * For list data consumed by combine(). * For list reference returned by getline(). In other word, in "combine" and "print", it might guess an encoding for the passing list data. If it cannot guess the encoding, the first encoding of the list is used. SEE ALSO
Encode, Encode::Guess AUTHOR
Makamaka Hannyaharamitu, <makamaka[at]cpan.org> COPYRIGHT AND LICENSE
Copyright 2008-2010 by Makamaka Hannyaharamitu This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself. perl v5.14.2 2010-04-26 Text::CSV::Encoded::Coder::EncodeGuess(3pm)
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