Perl CPAN module "Text::RecordParser"
Perl Perl6
Switch branches/tags
Nothing to show
Fetching latest commit…
Cannot retrieve the latest commit at this time.
Permalink
Failed to load latest commit information.
bin
lib/Text
t
.gitignore
Changes
INSTALL
MANIFEST
MANIFEST.SKIP
Makefile.PL
README
TODO

README

NAME
    Text::RecordParser - read record-oriented files

SYNOPSIS
      use Text::RecordParser;

      # use default record (\n) and field (,) separators
      my $p = Text::RecordParser->new( $file );

      # or be explicit
      my $p = Text::RecordParser->new({
          filename        => $file,
          field_separator => "\t",
      });

      $p->filename('foo.csv');

      # Split records on two newlines
      $p->record_separator("\n\n");

      # Split fields on tabs
      $p->field_separator("\t");

      # Skip lines beginning with hashes
      $p->comment( qr/^#/ );

      # Trim whitespace
      $p->trim(1);

      # Use the fields in the first line as column names
      $p->bind_header;

      # Get a list of the header fields (in order)
      my @columns = $p->field_list;

      # Extract a particular field from the next row
      my ( $name, $age ) = $p->extract( qw[name age] );

      # Return all the fields from the next row
      my @fields = $p->fetchrow_array;

      # Define a field alias
      $p->set_field_alias( name => 'handle' );

      # Return all the fields from the next row as a hashref
      my $record = $p->fetchrow_hashref;
      print $record->{'name'};
      # or
      print $record->{'handle'};

      # Return the record as an object with fields as accessors
      my $object = $p->fetchrow_object;
      print $object->name; # or $object->handle;

      # Get all data as arrayref of arrayrefs
      my $data = $p->fetchall_arrayref;

      # Get all data as arrayref of hashrefs
      my $data = $p->fetchall_arrayref( { Columns => {} } );

      # Get all data as hashref of hashrefs
      my $data = $p->fetchall_hashref('name');

DESCRIPTION
    This module is for reading record-oriented data in a delimited text
    file. The most common example have records separated by newlines and
    fields separated by commas or tabs, but this module aims to provide a
    consistent interface for handling sequential records in a file however
    they may be delimited. Typically this data lists the fields in the first
    line of the file, in which case you should call "bind_header" to bind
    the field name (or not, and it will be called implicitly). If the first
    line contains data, you can still bind your own field names via
    "bind_fields". Either way, you can then use many methods to get at the
    data as arrays or hashes.

METHODS
  new
    This is the object constructor. It takes a hash (or hashref) of
    arguments. Each argument can also be set through the method of the same
    name.

    *   filename

        The path to the file being read. If the filename is passed and the
        fh is not, then it will open a filehandle on that file and sets "fh"
        accordingly.

    *   comment

        A compiled regular expression identifying comment lines that should
        be skipped.

    *   data

        The data to read.

    *   fh

        The filehandle of the file to read.

    *   field_separator | fs

        The field separator (default is comma).

    *   record_separator | rs

        The record separator (default is newline).

    *   field_filter

        A callback applied to all the fields as they are read.

    *   header_filter

        A callback applied to the column names.

    *   trim

        Boolean to enable trimming of leading and trailing whitespace from
        fields (useful if splitting on whitespace only).

    See methods for each argument name for more information.

    Alternately, if you supply a single argument to "new", it will be
    treated as the "filename" argument.

  bind_fields
      $p->bind_fields( qw[ name rank serial_number ] );

    Takes an array of field names and memorizes the field positions for
    later use. If the input file has no header line but you still wish to
    retrieve the fields by name (or even if you want to call "bind_header"
    and then give your own field names), simply pass in the an array of
    field names you wish to use.

    Pass in an empty array reference to unset:

      $p->bind_field( [] ); # unsets fields

  bind_header
      $p->bind_header;
      my $name = $p->extract('name');

    Takes the fields from the next row under the cursor and assigns the
    field names to the values. Usually you would call this immediately after
    opening the file in order to bind the field names in the first row.

  comment
      $p->comment( qr/^#/ );  # Perl-style comments
      $p->comment( qr/^--/ ); # SQL-style comments

    Takes a regex to apply to a record to see if it looks like a comment to
    skip.

  data
      $p->data( $string );
      $p->data( \$string );
      $p->data( @lines );
      $p->data( [$line1, $line2, $line3] );
      $p->data( IO::File->new('<data') );

    Allows a scalar, scalar reference, glob, array, or array reference as
    the thing to read instead of a file handle.

    It's not advised to pass a filehandle to "data" as it will read the
    entire contents of the file rather than one line at a time if you set it
    via "fh".

  extract
      my ( $foo, $bar, $baz ) = $p->extract( qw[ foo bar baz ] );

    Extracts a list of fields out of the last row read. The field names must
    correspond to the field names bound either via "bind_fields" or
    "bind_header".

  fetchrow_array
      my @values = $p->fetchrow_array;

    Reads a row from the file and returns an array or array reference of the
    fields.

  fetchrow_hashref
      my $record = $p->fetchrow_hashref;
      print "Name = ", $record->{'name'}, "\n";

    Reads a line of the file and returns it as a hash reference. The keys of
    the hashref are the field names bound via "bind_fields" or
    "bind_header". If you do not bind fields prior to calling this method,
    the "bind_header" method will be implicitly called for you.

  fetchrow_object
      while ( my $object = $p->fetchrow_object ) {
          my $id   = $object->id;
          my $name = $object->naem; # <-- this will throw a runtime error
      }

    This will return the next data record as a Text::RecordParser::Object
    object that has read-only accessor methods of the field names and any
    aliases. This allows you to enforce field names, further helping ensure
    that your code is reading the input file correctly. That is, if you are
    using the "fetchrow_hashref" method to read each line, you may misspell
    the hash key and introduce a bug in your code. With this method, Perl
    will throw an error if you attempt to read a field not defined in the
    file's headers. Additionally, any defined field aliases will be created
    as additional accessor methods.

  fetchall_arrayref
      my $records = $p->fetchall_arrayref;
      for my $record ( @$records ) {
          print "Name = ", $record->[0], "\n";
      }

      my $records = $p->fetchall_arrayref( { Columns => {} } );
      for my $record ( @$records ) {
          print "Name = ", $record->{'name'}, "\n";
      }

    Like DBI's fetchall_arrayref, returns an arrayref of arrayrefs. Also
    accepts optional "{ Columns => {} }" argument to return an arrayref of
    hashrefs.

  fetchall_hashref
      my $records = $p->fetchall_hashref('id');
      for my $id ( keys %$records ) {
          my $record = $records->{ $id };
          print "Name = ", $record->{'name'}, "\n";
      }

    Like DBI's fetchall_hashref, this returns a hash reference of hash
    references. The keys of the top-level hashref are the field values of
    the field argument you supply. The field name you supply can be a field
    created by a "field_compute".

  fh
      open my $fh, '<', $file or die $!;
      $p->fh( $fh );

    Gets or sets the filehandle of the file being read.

  field_compute
    A callback applied to the fields identified by position (or field name
    if "bind_fields" or "bind_header" was called).

    The callback will be passed two arguments:

    1   The current field

    2   A reference to all the other fields, either as an array or hash
        reference, depending on the method which you called.

    If data looks like this:

      parent    children
      Mike      Greg,Peter,Bobby
      Carol     Marcia,Jane,Cindy

    You could split the "children" field into an array reference with the
    values like so:

      $p->field_compute( 'children', sub { [ split /,/, shift() ] } );

    The field position or name doesn't actually have to exist, which means
    you could create new, computed fields on-the-fly. E.g., if you data
    looks like this:

        1,3,5
        32,4,1
        9,5,4

    You could write a field_compute like this:

        $p->field_compute( 3,
            sub {
                my ( $cur, $others ) = @_;
                my $sum;
                $sum += $_ for @$others;
                return $sum;
            }
        );

    Field "3" will be created as the sum of the other fields. This allows
    you to further write:

        my $data = $p->fetchall_arrayref;
        for my $rec ( @$data ) {
            print "$rec->[0] + $rec->[1] + $rec->[2] = $rec->[3]\n";
        }

    Prints:

        1 + 3 + 5 = 9
        32 + 4 + 1 = 37
        9 + 5 + 4 = 18

  field_filter
      $p->field_filter( sub { $_ = shift; uc(lc($_)) } );

    A callback which is applied to each field. The callback will be passed
    the current value of the field. Whatever is passed back will become the
    new value of the field. The above example capitalizes field values. To
    unset the filter, pass in the empty string.

  field_list
      $p->bind_fields( qw[ foo bar baz ] );
      my @fields = $p->field_list;
      print join ', ', @fields; # prints "foo, bar, baz"

    Returns the fields bound via "bind_fields" (or "bind_header").

  field_positions
      my %positions = $p->field_positions;

    Returns a hash of the fields and their positions bound via "bind_fields"
    (or "bind_header"). Mostly for internal use.

  field_separator
      $p->field_separator("\t");     # splits fields on tabs
      $p->field_separator('::');     # splits fields on double colons
      $p->field_separator(qr/\s+/);  # splits fields on whitespace
      my $sep = $p->field_separator; # returns the current separator

    Gets and sets the token to use as the field delimiter. Regular
    expressions can be specified using qr//. If not specified, it will take
    a guess based on the filename extension ("comma" for ".txt," ".dat," or
    ".csv"; "tab" for ".tab"). The default is a comma.

  filename
      $p->filename('/path/to/file.dat');

    Gets or sets the complete path to the file to be read. If a file is
    already opened, then the handle on it will be closed and a new one
    opened on the new file.

  get_field_aliases
      my @aliases = $p->get_field_aliases('name');

    Allows you to define alternate names for fields, e.g., sometimes your
    input file calls city "town" or "township," sometimes a file uses
    "Moniker" instead of "name."

  header_filter
      $p->header_filter( sub { $_ = shift; s/\s+/_/g; lc $_ } );

    A callback applied to column header names. The callback will be passed
    the current value of the header. Whatever is returned will become the
    new value of the header. The above example collapses spaces into a
    single underscore and lowercases the letters. To unset a filter, pass in
    the empty string.

  record_separator
      $p->record_separator("\n//\n");
      $p->field_separator("\n");

    Gets and sets the token to use as the record separator. The default is a
    newline ("\n").

    The above example would read a file that looks like this:

      field1
      field2
      field3
      // 
      data1
      data2
      data3
      //

  set_field_alias
      $p->set_field_alias({
          name => 'Moniker,handle',        # comma-separated string
          city => [ qw( town township ) ], # or anonymous arrayref
      });

    Allows you to define alternate names for fields, e.g., sometimes your
    input file calls city "town" or "township," sometimes a file uses
    "Moniker" instead of "name."

  trim
      my $trim_value = $p->trim(1);

    Provide "true" argument to remove leading and trailing whitespace from
    fields. Use a "false" argument to disable.

AUTHOR
    Ken Youens-Clark <kclark@cpan.org>

SOURCE
    http://github.com/kyclark/text-recordparser

CREDITS
    Thanks to the following:

    *   Benjamin Tilly

        For Text::xSV, the inspirado for this module

    *   Tim Bunce et al.

        For DBI, from which many of the methods were shamelessly stolen

    *   Tom Aldcroft

        For contributing code to make it easy to parse whitespace-delimited
        data

    *   Liya Ren

        For catching the column-ordering error when parsing with
        "no-headers"

    *   Sharon Wei

        For catching bug in "extract" that sets up infinite loops

    *   Lars Thegler

        For bug report on missing "script_files" arg in Build.PL

BUGS
    None known. Please use http://rt.cpan.org/ for reporting bugs.

LICENSE AND COPYRIGHT
    Copyright (C) 2006-10 Ken Youens-Clark. All rights reserved.

    This program is free software; you can redistribute it and/or modify it
    under the terms of the GNU General Public License as published by the
    Free Software Foundation; version 2.

    This program is distributed in the hope that it will be useful, but
    WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
    Public License for more details.