Bio::Index::Blast - Indexes Blast reports and supports retrieval based on query
accession(s)
use strict;
use Bio::Index::Blast;
my ($indexfile,$file1,$file2,$query);
my $index = Bio::Index::Blast->new(-filename => $indexfile,
-write_flag => 1);
$index->make_index($file1,$file2);
my $fh = $index->get_stream($query);
my $blast_report = Bio::SearchIO->new(-noclose => 1,
-format => 'blast',
-fh => $fh);
my $result = $blast_report->next_result;
print $result->algorithm, "\n";
my $hit = $result->next_hit;
print $hit->description, "\n";
my $hsp = $hit->next_hsp;
print $hsp->bits, "\n";
This object allows one to build an index on a blast file (or files) and provide
quick access to the blast report for that accession.
This also allows for ID parsing using a callback:
$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;
}
The indexer is capable of indexing based on multiple IDs passed back from the
callback; this is assuming of course all IDs are unique.
Note: for best results 'use strict'.
User feedback is an integral part of the evolution of this and other Bioperl
modules. Send your comments and suggestions preferably to the Bioperl mailing
list. Your participation is much appreciated.
[email protected] - General discussion
http://bioperl.org/wiki/Mailing_lists - About the mailing lists
Please direct usage questions or support issues to the mailing list:
[email protected]
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 of the bugs
and their resolution. Bug reports can be submitted via the web:
https://github.com/bioperl/bioperl-live/issues
Email jason-at-bioperl-dot-org
The rest of the documentation details each of the object methods. Internal
methods are usually preceded with a _
Usage : $index = Bio::Index::Abstract->new(
-filename => $dbm_file,
-write_flag => 0,
-dbm_package => 'DB_File',
-verbose => 0);
Function: Returns a new index object. If filename is
specified, then open_dbm() is immediately called.
Bio::Index::Abstract->new() will usually be called
directly only when opening an existing index.
Returns : A new index object
Args : -filename The name of the dbm index file.
-write_flag TRUE if write access to the dbm file is
needed.
-dbm_package The Perl dbm module to use for the
index.
-verbose Print debugging output to STDERR if
TRUE.
Title : fetch_report
Usage : my $blastreport = $idx->fetch_report($id);
Function: Returns a Bio::SearchIO report object
for a specific blast report
Returns : Bio::SearchIO
Args : valid id
Title : fetch_result
Usage : my $blastreport = $idx->fetch_result($id);
Function: Returns a Bio::SearchIO report object
for a specific blast report
Returns : Bio::SearchIO
Args : valid id
Note : alias of fetch_report()
Title : _index_file
Usage : $index->_index_file( $file_name, $i )
Function: Specialist function to index BLAST report file(s).
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 blast dbs.
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 Blast Query ID parser for Bio::Index::Blast.pm
Returns $1 from applying the regexp /^>\s*(\S+)/
to $header.
Returns : ID string
Args : a header line string
Title : blast_parser_type
Usage : $index->blast_parser_type() # returns
Function: Get/Set SearchIO-based text (-m0) BLAST parser. Only values in
local %VALID_PARSERS hash allowed.
Returns : String
Args : [optional]
Note : This only allows simple text-based parsing options; tabular, XML,
or others are not supported (see Bio::Index::BlastTable for tab
output).
Title : filename
Usage : $value = $self->filename();
$self->filename($value);
Function: Gets or sets the name of the dbm index file.
Returns : The current value of filename
Args : Value of filename if setting, or none if
getting the value.
Title : write_flag
Usage : $value = $self->write_flag();
$self->write_flag($value);
Function: Gets or sets the value of write_flag, which
is whether the dbm file should be opened with
write access.
Returns : The current value of write_flag (default 0)
Args : Value of write_flag if setting, or none if
getting the value.
Usage : $value = $self->dbm_package();
$self->dbm_package($value);
Function: Gets or sets the name of the Perl dbm module used.
If the value is unset, then it returns the value of
the package variable $USE_DBM_TYPE or if that is
unset, then it chooses the best available dbm type,
choosing 'DB_File' in preference to 'SDBM_File'.
Bio::Abstract::Index may work with other dbm file
types.
Returns : The current value of dbm_package
Args : Value of dbm_package if setting, or none if
getting the value.
Title : get_stream
Usage : $stream = $index->get_stream( $id );
Function: Returns a file handle with the file pointer
at the approprite place
This provides for a way to get the actual
file contents and not an object
WARNING: you must parse the record deliminter
*yourself*. Abstract won't do this for you
So this code
$fh = $index->get_stream($myid);
while( <$fh> ) {
# do something
}
will parse the entire file if you do not put in
a last statement in, like
while( <$fh> ) {
/^\/\// && last; # end of record
# do something
}
Returns : A filehandle object
Args : string represents the accession number
Notes : This method should not be used without forethought
Usage : $index->open_dbm()
Function: Opens the dbm file associated with the index
object. Write access is only given if explicitly
asked for by calling new(-write => 1) or having set
the write_flag(1) on the index object. The type of
dbm file opened is that returned by dbm_package().
The name of the file to be is opened is obtained by
calling the filename() method.
Example : $index->_open_dbm()
Returns : 1 on success
Title : _version
Usage : $type = $index->_version()
Function: Returns a string which identifes the version of an
index module. Used to permanently identify an index
file as having been created by a particular version
of the index module. Must be provided by the sub class
Example :
Returns :
Args : none
Title : _filename
Usage : $index->_filename( FILE INT )
Function: Indexes the file
Example :
Returns :
Args :
Title : _file_handle
Usage : $fh = $index->_file_handle( INT )
Function: Returns an open filehandle for the file
index INT. On opening a new filehandle it
caches it in the @{$index->_filehandle} array.
If the requested filehandle is already open,
it simply returns it from the array.
Example : $fist_file_indexed = $index->_file_handle( 0 );
Returns : ref to a filehandle
Args : INT
Title : _file_count
Usage : $index->_file_count( INT )
Function: Used by the index building sub in a sub class to
track the number of files indexed. Sets or gets
the number of files indexed when called with or
without an argument.
Example :
Returns : INT
Args : INT
Title : add_record
Usage : $index->add_record( $id, @stuff );
Function: Calls pack_record on @stuff, and adds the result
of pack_record to the index database under key $id.
If $id is a reference to an array, then a new entry
is added under a key corresponding to each element
of the array.
Example : $index->add_record( $id, $fileNumber, $begin, $end )
Returns : TRUE on success or FALSE on failure
Args : ID LIST
Title : pack_record
Usage : $packed_string = $index->pack_record( LIST )
Function: Packs an array of scalars into a single string
joined by ASCII 034 (which is unlikely to be used
in any of the strings), and returns it.
Example : $packed_string = $index->pack_record( $fileNumber, $begin, $end )
Returns : STRING or undef
Args : LIST
Title : unpack_record
Usage : $index->unpack_record( STRING )
Function: Splits the sting provided into an array,
splitting on ASCII 034.
Example : ( $fileNumber, $begin, $end ) = $index->unpack_record( $self->db->{$id} )
Returns : A 3 element ARRAY
Args : STRING containing ASCII 034
Title : DESTROY
Usage : Called automatically when index goes out of scope
Function: Closes connection to database and handles to
sequence files
Returns : NEVER
Args : NONE