Bio::SearchIO::blast_pull - A parser for BLAST output


    # do not use this class directly it is available through Bio::SearchIO
    use Bio::SearchIO;
    my $in = Bio::SearchIO->new(-format => 'blast_pull',
                               -file   => 't/data/new_blastn.txt');
    while (my $result = $in->next_result) {
        # this is a Bio::Search::Result::BlastPullResult object
        print "Results for ", $result->query_name(), "\n";
        while (my $hit = $result->next_hit) {
            print $hit->name(), "\n";
            while (my $hsp = $hit->next_hsp) {
                print "length is ", $hsp->length(), "\n";


This object implements a pull-parser for BLAST output. It is fast since it only does work on request (hence 'pull').

Currently only NCBI BLASTN and BLASTP are supported.


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Please direct usage questions or support issues to the mailing list:

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.

Reporting Bugs

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:

AUTHOR - Sendu Bala



The rest of the documentation details each of the object methods. Internal methods are usually preceded with a _


 Title   : new
 Usage   : my $obj = Bio::SearchIO::blast_pull->new();
 Function: Builds a new Bio::SearchIO::blast_pull object 
 Returns : Bio::SearchIO::blast_pull
 Args    : -fh/-file => BLAST output filename
           -format   => 'blast_pull'
           -evalue   => float or scientific notation number to be used
                        as an evalue cutoff for hits
           -score    => integer or scientific notation number to be used
                        as a score value cutoff for hits
           -piped_behaviour => 'temp_file'|'memory'|'sequential_read'

           -piped_behaviour defines what the parser should do if the input is
            an unseekable filehandle (eg. piped input), see
            Bio::PullParserI::chunk for details. Default is 'memory'.


 Title   : next_result
 Usage   : my $hit = $searchio->next_result;
 Function: Returns the next Result from a search
 Returns : Bio::Search::Result::ResultI object
 Args    : none


 Title   : result_count
 Usage   : my $count = $searchio->result_count
 Function: Returns the number of results we have processed.
 Returns : integer
 Args    : none


 Title   : rewind
 Usage   : $searchio->rewind;
 Function: Allow one to reset the Result iterator to the beginning, so that
           next_result() will subsequently return the first result and so on.

           NB: result objects are not cached, so you will get new result objects
           each time you rewind. Also, note that result_count() counts the
           number of times you have called next_result(), so will not be able
           tell you how many results there were in the file if you use rewind().

 Returns : n/a
 Args    : none