split text file to some part. each part is started from line start to line end.
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README.md

NAME

Text::Parts - split text file to some parts(from one line start to another/same line end)

SYNOPSIS

If you want to split a text file to some number of parts:

use Text::Parts;


my $splitter = Text::Parts->new(file => $file);
my (@parts) = $splitter->split(num => 4);

foreach my $part (@parts) {
   while(my $l = $part->getline) { # or <$part>
      # ...
   }
}

If you want to split a text file by about specified size:

use Text::Parts;


my $splitter = Text::Parts->new(file => $file);
my (@parts) = $splitter->split(size => 10); # size of part will be more than 10.
# same as the previous example

If you want to split CSV file:

use Text::Parts;
use Text::CSV_XS; # don't work with Text::CSV_PP if you want to use {binary => 1} option
                  # I don't recommend to use it for CSV which has multiline lines in columns.


my $csv = Text::CSV_XS->new();
my $splitter = Text::Parts->new(file => $file, parser => $csv);
my (@parts) = $splitter->split(num => 4);


foreach my $part (@parts) {
   while(my $col = $part->getline_parser) { # getline_parser returns parsed result
      print join "\t", @$col;
      # ...
   }
}

Write splitted parts to files:

$splitter->write_files('file%d.csv', num => 4);


my $i = 0;
foreach my $part ($splitter->slit(num => 4)) {
  $part->write_file("file" . $i++ . '.csv');
}

with Parallel::ForkManager:

my $splitter = Text::Parts->new(file => $file);
my (@parts) = $splitter->split(num => 4);
my $pm = new Parallel::ForkManager(4);


foreach my $part (@parts) {
  $pm->start and next; # do the fork


  while (my $l = $part->getline) {
    # ...
  }
}


$pm->wait_all_children;

NOTE THAT: If the file is on the same disk, fork is no use. Maybe, using fork makes sense when the file is on RAID (I haven't try it).

DESCRIPTION

This module splits file by specified number of part. The range of each part is from one line start to another/same line end. For example, file content is the following:

1111
22222222222222222222
3333
4444

If $splitter->split(num => 3), split like the following:

1st part: 1111 22222222222222222222

2nd part: 3333

3rd part: 4444

At first, split method tries to split by bytes of file size / 3, Secondly, tries to split by bytes of rest file size / the number of rest part. So that:

1st part : 36 bytes / 3 = 12 byte + bytes to line end(if needed)
2nd part : (36 - 26 bytes) / 2 = 5 byte + bytes to line end(if needed)
last part: rest part of file

METHODS

new

$s = Text::Parts->new(file => $filename);
$s = Text::Parts->new(file => $filename, parser => Text::CSV_XS->new({binary => 1}));

Constructor. It can take following options:

num

number how many you want to split.

size

file size how much you want to split. This value is used for calculating num. If file size is 100 and this value is 25, num is 4.

file

target file which you want to split.

parser

Pass parser object(like Text::CSV_XS->new()). The object must have method which takes filehandle and whose name is getline as default. If the object's method is different name, pass the name to parser_method option.

parser_method

name of parser's method. default is getline.

check_line_start

If this options is true, check line start and move to this position before <$fh> or parser's getline/parser_method. It may be useful when parser's getline/parser_method method doesn't work correctly when parsing wrong format.

default value is 0.

no_open

If this option is true, don't open file on creating Text::Parts::Part object. You need to call open_and_seek method from the object when you read the file (But, all and write_file checks this option, so you don't need to call open_and_seek).

This option is required when you pass too much number, which is more than OS's open file limit, to split method.

file

my $file = $s->file;
$s->file($filename);

get/set target file.

parser

my $parser_object = $s->parser;
$s->parser($parser_object);

get/set parser object.

parser_method

my $method = $s->parser_method;
$s->parser_method($method);

get/set parser method.

split

my @parts = $s->split(num => $num);
my @parts = $s->split(size => $size);
my @parts = $s->split(num => $num, max_num => 3);

Try to split target file to $num of parts. The returned value is array of Text::Parts::Part object. If you pass size => bytes, calculate $num from file size / $size.

This method doesn't actually split file, only calculate the start and end position of parts.

This returns array of Text::Parts::Part object. See "Text::Parts::Part METHODS".

If you set max_num, only split number of max_num.

my @parts = $s->split(num => 5, max_num => 2);

This tries to split 5 parts, but only 2 parts are returned. This is useful to try to test a few parts of too many parts.

eol

my $eol = $s->eol;
$s->eol($eol);

get/set end of line string. default value is $/.

write_files

@filenames = $s->write_files('path/to/name%d.txt', num => 4);

name_format is the format of filename. %d is replaced by number. For example:

path/to/name1.txt
path/to/name2.txt
path/to/name3.txt
path/to/name4.txt

The rest of arguments are as same as split except the following 2 options.

  • code

    code option takes code reference which would be done immediately after file had been written. If you pass code option as the following:

    @filenames = $s->write_files('path/to/name%d.txt', num => 4, code => \&do_after_split)
    

    splitted file name is given to &do_after_split:

    sub do_after_split {
       my $filename = shift; # 'path/to/name1.txt'
       # ...
       unlink $filename;
    }
    
  • start_number

    @filenames = $s->write_files('path/to/name%d.txt', num => 4, start_number => 0);
    # $filenames[0] is 'path/to/name0.txt'
    

    This is used for filename.

    if start_number is 0.

    path/to/name0.txt
    path/to/name1.txt
    ...
    

    if start_number is 1 (default).

    path/to/name1.txt
    path/to/name2.txt
    ...
    

    if start_number is 2

    path/to/name2.txt
    path/to/name3.txt
    ...
    
  • last_number

    If last_number is specified, stop to split file when number reaches last_number. Note that this option override max_num.

    @filenames = $s->write_files('path/to/name%d.txt', num => 4, start_number => 0, last_number => 1);
    # $filenames[0] is 'path/to/name0.txt'
    # $filenames[1] is 'path/to/name1.txt'
    # $filenames[2] doesn't exist
    

Text::Parts::Part METHODS

Text::Parts::Part objects are returned by split method.

getline

my $line = $part->getline;

return 1 line. You can use <$part>, also.

my $line = <$part>

getline_parser

my $parsed = $part->getline_parser;

returns parsed result.

all

my $all = $part->all;
$part->all(\$all);

return all of the part. just read from start to end position.

If scalar reference is passed as argument, the content of the part is into the passed scalar.

This method checks no_open option. If no_open is true, open file before writing file and close file after writing.

eof

$part->eof;

If current position is the end of parts, return true.

write_file

$part->write_file($filename);

Write the contents of the part to $filename.

This method checks no_open option. If no_open is true, open file before writing file and close file after writing.

open_and_seek

$part->open_and_seek;

If the object is created with no_open true, you need to call this method before reading file.

close

$part->close;

close file handle.

is_opened

$part->is_opened;

If file handle is opened, return true.

AUTHOR

Ktat, <ktat at cpan.org>

BUGS

Please report any bugs or feature requests to bug-text-parts at rt.cpan.org, or through the web interface at http://rt.cpan.org/NoAuth/ReportBug.html?Queue=Text-Parts. I will be notified, and then you'll automatically be notified of progress on your bug as I make changes.

SUPPORT

You can find documentation for this module with the perldoc command.

perldoc Text::Parts

You can also look for information at:

ACKNOWLEDGEMENTS

LICENSE AND COPYRIGHT

Copyright 2011 Ktat.

This program is free software; you can redistribute it and/or modify it under the terms of either: the GNU General Public License as published by the Free Software Foundation; or the Artistic License.

See http://dev.perl.org/licenses/ for more information.