| Bio::Index::Fasta(3pm) | User Contributed Perl Documentation | Bio::Index::Fasta(3pm) |
Bio::Index::Fasta - Interface for indexing (multiple) fasta files
# Make an index for one or more fasta files
use Bio::Index::Fasta;
use strict;
my $Index_File_Name = shift;
my $inx = Bio::Index::Fasta->new(-filename => $Index_File_Name,
-write_flag => 1);
$inx->make_index(@ARGV);
# Once the index is made it can accessed, either in the
# same script or a different one
use Bio::Index::Fasta;
use strict;
my $Index_File_Name = shift;
my $inx = Bio::Index::Fasta->new(-filename => $Index_File_Name);
my $out = Bio::SeqIO->new(-format => 'Fasta',
-fh => \*STDOUT);
foreach my $id (@ARGV) {
my $seq = $inx->fetch($id); # Returns Bio::Seq object
$out->write_seq($seq);
}
# or, alternatively
my $id;
my $seq = $inx->get_Seq_by_id($id); # identical to fetch()
Inherits functions for managing dbm files from Bio::Index::Abstract.pm, and provides the basic funtionality for indexing fasta files, and retrieving the sequence from them. For best results 'use strict'.
Bio::Index::Fasta supports the Bio::DB::BioSeqI interface, meaning it can be used as a Sequence database for other parts of bioperl
Additional example code is available in scripts/index/.
Note that by default the key for the sequence will be the first continuous string after the '>' in the fasta header. If you want to use a specific substring of the fasta header you must use the id_parser() method.
You can also set or customize the unique key used to retrieve by writing your own function and calling the id_parser() method. For example:
$inx->id_parser(\&get_id);
# make the index
$inx->make_index($file_name);
# here is where the retrieval key is specified
sub get_id {
my $line = shift;
$line =~ /^>.+gi\|(\d+)/;
$1;
}
User feedback is an integral part of the evolution of this and other Bioperl modules. Send your comments and suggestions preferably to one of the Bioperl mailing lists. Your participation is much appreciated.
bioperl-l@bioperl.org - General discussion http://bioperl.org/wiki/Mailing_lists - About the mailing lists
Please direct usage questions or support issues to the mailing list:
bioperl-l@bioperl.org
rather than to the module maintainer directly. Many experienced and reponsive experts will be able look at the problem and quickly address it. Please include a thorough description of the problem with code and data examples if at all possible.
Report bugs to the Bioperl bug tracking system to help us keep track the bugs and their resolution. Bug reports can be submitted via the web:
https://github.com/bioperl/bioperl-live/issues
Email - jgrg@sanger.ac.uk
The rest of the documentation details each of the object methods. Internal methods are usually preceded with a _
Title : _file_format
Function: The file format for this package, which is needed
by the SeqIO system when reading the sequence.
Returns : 'Fasta'
Title : _index_file
Usage : $index->_index_file( $file_name, $i )
Function: Specialist function to index FASTA format files.
Is provided with a filename and an integer
by make_index in its SUPER class.
Example :
Returns :
Args :
Title : id_parser
Usage : $index->id_parser( CODE )
Function: Stores or returns the code used by record_id to
parse the ID for record from a string. Useful
for (for instance) specifying a different
parser for different flavours of FASTA file.
Returns \&default_id_parser (see below) if not
set. If you supply your own id_parser
subroutine, then it should expect a fasta
description line. An entry will be added to
the index for each string in the list returned.
Example : $index->id_parser( \&my_id_parser )
Returns : ref to CODE if called without arguments
Args : CODE
Title : default_id_parser
Usage : $id = default_id_parser( $header )
Function: The default Fasta ID parser for Fasta.pm
Returns $1 from applying the regexp /^>\s*(\S+)/
to $header.
Returns : ID string
Args : a fasta header line string
| 2020-10-28 | perl v5.30.3 |