Provided by: libbio-perl-perl_1.7.2-3_all bug


       Bio::SeqIO - Handler for SeqIO Formats


           use Bio::SeqIO;

           $in  = Bio::SeqIO->new(-file => "inputfilename" ,
                                  -format => 'Fasta');
           $out = Bio::SeqIO->new(-file => ">outputfilename" ,
                                  -format => 'EMBL');

           while ( my $seq = $in->next_seq() ) {

         # Now, to actually get at the sequence object, use the standard Bio::Seq
         # methods (look at Bio::Seq if you don't know what they are)

           use Bio::SeqIO;

           $in  = Bio::SeqIO->new(-file => "inputfilename" ,
                                  -format => 'genbank');

           while ( my $seq = $in->next_seq() ) {
              print "Sequence ",$seq->id, " first 10 bases ",
                    $seq->subseq(1,10), "\n";

         # The SeqIO system does have a filehandle binding. Most people find this
         # a little confusing, but it does mean you can write the world's
         # smallest reformatter

           use Bio::SeqIO;

           $in  = Bio::SeqIO->newFh(-file => "inputfilename" ,
                                    -format => 'Fasta');
           $out = Bio::SeqIO->newFh(-format => 'EMBL');

           # World's shortest Fasta<->EMBL format converter:
           print $out $_ while <$in>;


       Bio::SeqIO is a handler module for the formats in the SeqIO set (eg, Bio::SeqIO::fasta).
       It is the officially sanctioned way of getting at the format objects, which most people
       should use.

       The Bio::SeqIO system can be thought of like biological file handles.  They are attached
       to filehandles with smart formatting rules (eg, genbank format, or EMBL format, or binary
       trace file format) and can either read or write sequence objects (Bio::Seq objects, or
       more correctly, Bio::SeqI implementing objects, of which Bio::Seq is one such object). If
       you want to know what to do with a Bio::Seq object, read Bio::Seq.

       The idea is that you request a stream object for a particular format.  All the stream
       objects have a notion of an internal file that is read from or written to. A particular
       SeqIO object instance is configured for either input or output. A specific example of a
       stream object is the Bio::SeqIO::fasta object.

       Each stream object has functions




       As an added bonus, you can recover a filehandle that is tied to the SeqIO object, allowing
       you to use the standard <> and print operations to read and write sequence objects:

           use Bio::SeqIO;

           $stream = Bio::SeqIO->newFh(-format => 'Fasta',
                                       -fh     => \*ARGV);
           # read from standard input or the input filenames

           while ( $seq = <$stream> ) {
               # do something with $seq


           print $stream $seq; # when stream is in output mode

       This makes the simplest ever reformatter

           use strict;
           my $format1 = shift;
           my $format2 = shift || die
              "Usage: reformat format1 format2 < input > output";

           use Bio::SeqIO;

           my $in  = Bio::SeqIO->newFh(-format => $format1, -fh => \*ARGV );
           my $out = Bio::SeqIO->newFh(-format => $format2 );
           # Note: you might want to quote -format to keep older
           # perl's from complaining.

           print $out $_ while <$in>;


          $seqIO = Bio::SeqIO->new(-file   => 'seqs.fasta', -format => $format);
          $seqIO = Bio::SeqIO->new(-fh     => \*FILEHANDLE, -format => $format);
          $seqIO = Bio::SeqIO->new(-string => $string     , -format => $format);
          $seqIO = Bio::SeqIO->new(-format => $format);

       The new() class method constructs a new Bio::SeqIO object. The returned object can be used
       to retrieve or print Seq objects. new() accepts the following parameters:

            A file path to be opened for reading or writing.  The usual Perl conventions apply:

               'file'       # open file for reading
               '>file'      # open file for writing
               '>>file'     # open file for appending
               '+<file'     # open file read/write

            To read from or write to a piped command, open a filehandle and use the -fh option.

       -fh  You may use new() with a opened filehandle, provided as a glob reference. For
            example, to read from STDIN:

               my $seqIO = Bio::SeqIO->new(-fh => \*STDIN);

            A string filehandle is handy if you want to modify the output in the memory, before
            printing it out. The following program reads in EMBL formatted entries from a file
            and prints them out in fasta format with some HTML tags:

              use Bio::SeqIO;
              use IO::String;
              my $in = Bio::SeqIO->new(-file => "emblfile",
                                       -format => 'EMBL');
              while ( my $seq = $in->next_seq() ) {
                  # the output handle is reset for every file
                  my $stringio = IO::String->new($string);
                  my $out = Bio::SeqIO->new(-fh => $stringio,
                                            -format => 'fasta');
                  # output goes into $string
                  # modify $string
                  $string =~ s|(>)(\w+)|$1<font color="Red">$2</font>|g;
                  # print into STDOUT
                  print $string;

            Filehandles can also be used to read from or write to a piped command:

              use Bio::SeqIO;
              #convert .fastq.gz to .fasta
              open my $zcat, 'zcat seq.fastq.gz |' or die $!;
              my $in=Bio::SeqIO->new(-fh=>$zcat,
              my $out=Bio::SeqIO->new(-file=>'>seq.fasta',
              while (my $seq=$in->next_seq) {

            A string to read the sequences from. For example:

               my $string = ">seq1\nACGCTAGCTAGC\n";
               my $seqIO = Bio::SeqIO->new(-string => $string);

            Specify the format of the file.  Supported formats include fasta, genbank, embl,
            swiss (SwissProt), Entrez Gene and tracefile formats such as abi (ABI) and scf. There
            are many more, for a complete listing see the SeqIO HOWTO

            If no format is specified and a filename is given then the module will attempt to
            deduce the format from the filename suffix. If there is no suffix that Bioperl
            understands then it will attempt to guess the format based on file content. If this
            is unsuccessful then SeqIO will throw a fatal error.

            The format name is case-insensitive: 'FASTA', 'Fasta' and 'fasta' are all valid.

            Currently, the tracefile formats (except for SCF) require installation of the
            external Staden "io_lib" package, as well as the Bio::SeqIO::staden::read package
            available from the bioperl-ext repository.

            Sets the alphabet ('dna', 'rna', or 'protein'). When the alphabet is set then Bioperl
            will not attempt to guess what the alphabet is. This may be important because Bioperl
            does not always guess correctly.

            By default, all files (or filehandles) opened for writing sequences will be flushed
            after each write_seq() (making the file immediately usable).  If you do not need this
            facility and would like to marginally improve the efficiency of writing multiple
            sequences to the same file (or filehandle), pass the -flush option '0' or any other
            value that evaluates as defined but false:

              my $gb = Bio::SeqIO->new(-file   => "<gball.gbk",
                                       -format => "gb");
              my $fa = Bio::SeqIO->new(-file   => ">gball.fa",
                                       -format => "fasta",
                                       -flush  => 0); # go as fast as we can!
              while($seq = $gb->next_seq) { $fa->write_seq($seq) }

            Provide a Bio::Factory::SequenceFactoryI object. See the sequence_factory() method.

            Provide a Bio::Factory::LocationFactoryI object. See the location_factory() method.

            Provide a Bio::Factory::ObjectBuilderI object. See the object_builder() method.

          $fh = Bio::SeqIO->newFh(-fh => \*FILEHANDLE, -format=>$format);
          $fh = Bio::SeqIO->newFh(-format => $format);
          # etc.

       This constructor behaves like new(), but returns a tied filehandle rather than a
       Bio::SeqIO object.  You can read sequences from this object using the familiar <>
       operator, and write to it using print().  The usual array and $_ semantics work.  For
       example, you can read all sequence objects into an array like this:

         @sequences = <$fh>;

       Other operations, such as read(), sysread(), write(), close(), and printf() are not


       See below for more detailed summaries.  The main methods are:

   $sequence = $seqIO->next_seq()
       Fetch the next sequence from the stream, or nothing if no more.

   $seqIO->write_seq($sequence [,$another_sequence,...])
       Write the specified sequence(s) to the stream.

       These provide the tie interface.  See perltie for more details.


   Mailing Lists
       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.
                  - General discussion  - About the mailing lists

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

       rather than to the module maintainer directly. Many experienced and responsive 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 the bugs and their
       resolution.  Bug reports can be submitted via the web:

AUTHOR - Ewan Birney, Lincoln Stein



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

        Title   : new
        Usage   : $stream = Bio::SeqIO->new(-file => 'sequences.fasta',
                                            -format => 'fasta');
        Function: Returns a new sequence stream
        Returns : A Bio::SeqIO stream initialised with the appropriate format
        Args    : Named parameters indicating where to read the sequences from or to
                  write them to:
                    -file   => filename, OR
                    -fh     => filehandle to attach to, OR
                    -string => string

                  Additional arguments, all with reasonable defaults:
                    -format     => format of the sequences, usually auto-detected
                    -alphabet   => 'dna', 'rna', or 'protein'
                    -flush      => 0 or 1 (default: flush filehandles after each write)
                    -seqfactory => sequence factory
                    -locfactory => location factory
                    -objbuilder => object builder

       See Bio::SeqIO::Handler

        Title   : newFh
        Usage   : $fh = Bio::SeqIO->newFh(-file=>$filename,-format=>'Format')
        Function: Does a new() followed by an fh()
        Example : $fh = Bio::SeqIO->newFh(-file=>$filename,-format=>'Format')
                  $sequence = <$fh>;   # read a sequence object
                  print $fh $sequence; # write a sequence object
        Returns : filehandle tied to the Bio::SeqIO::Fh class
        Args    :

       See Bio::SeqIO::Fh

        Title   : fh
        Usage   : $obj->fh
        Function: Get or set the IO filehandle
        Example : $fh = $obj->fh;      # make a tied filehandle
                  $sequence = <$fh>;   # read a sequence object
                  print $fh $sequence; # write a sequence object
        Returns : filehandle tied to Bio::SeqIO class
        Args    : none

        Title   : next_seq
        Usage   : $seq = stream->next_seq
        Function: Reads the next sequence object from the stream and returns it.

                  Certain driver modules may encounter entries in the stream
                  that are either misformatted or that use syntax not yet
                  understood by the driver. If such an incident is
                  recoverable, e.g., by dismissing a feature of a feature
                  table or some other non-mandatory part of an entry, the
                  driver will issue a warning. In the case of a
                  non-recoverable situation an exception will be thrown.  Do
                  not assume that you can resume parsing the same stream
                  after catching the exception. Note that you can always turn
                  recoverable errors into exceptions by calling

        Returns : a Bio::Seq sequence object, or nothing if no more sequences
                  are available

        Args    : none

       See Bio::Root::RootI, Bio::Factory::SeqStreamI, Bio::Seq

        Title   : write_seq
        Usage   : $stream->write_seq($seq)
        Function: writes the $seq object into the stream
        Returns : 1 for success and 0 for error
        Args    : Bio::Seq object

        Title   : format
        Usage   : $format = $stream->format()
        Function: Get the sequence format
        Returns : sequence format, e.g. fasta, fastq
        Args    : none

        Title   : alphabet
        Usage   : $self->alphabet($newval)
        Function: Set/get the molecule type for the Seq objects to be created.
        Example : $seqio->alphabet('protein')
        Returns : value of alphabet: 'dna', 'rna', or 'protein'
        Args    : newvalue (optional)
        Throws  : Exception if the argument is not one of 'dna', 'rna', or 'protein'

        Title   : _load_format_module
        Usage   : *INTERNAL SeqIO stuff*
        Function: Loads up (like use) a module at run time on demand
        Example :
        Returns :
        Args    :

        Title   : _concatenate_lines
        Usage   : $s = _concatenate_lines($line, $continuation_line)
        Function: Private. Concatenates two strings assuming that the second stems
                  from a continuation line of the first. Adds a space between both
                  unless the first ends with a dash.

                  Takes care of either arg being empty.
        Example :
        Returns : A string.
        Args    :

        Title   : _filehandle
        Usage   : $obj->_filehandle($newval)
        Function: This method is deprecated. Call _fh() instead.
        Example :
        Returns : value of _filehandle
        Args    : newvalue (optional)

        Title   : _guess_format
        Usage   : $obj->_guess_format($filename)
        Function: guess format based on file suffix
        Example :
        Returns : guessed format of filename (lower case)
        Args    :
        Notes   : formats that _filehandle() will guess include fasta,
                  genbank, scf, pir, embl, raw, gcg, ace, bsml, swissprot,
                  fastq and phd/phred

        Title   : sequence_factory
        Usage   : $seqio->sequence_factory($seqfactory)
        Function: Get/Set the Bio::Factory::SequenceFactoryI
        Returns : Bio::Factory::SequenceFactoryI
        Args    : [optional] Bio::Factory::SequenceFactoryI

        Title   : object_factory
        Usage   : $obj->object_factory($newval)
        Function: This is an alias to sequence_factory with a more generic name.
        Example :
        Returns : value of object_factory (a scalar)
        Args    : on set, new value (a scalar or undef, optional)

        Title   : sequence_builder
        Usage   : $seqio->sequence_builder($seqfactory)
        Function: Get/Set the Bio::Factory::ObjectBuilderI used to build sequence
                  objects. This applies to rich sequence formats only, e.g. genbank
                  but not fasta.

                  If you do not set the sequence object builder yourself, it
                  will in fact be an instance of L<Bio::Seq::SeqBuilder>, and
                  you may use all methods documented there to configure it.

        Returns : a Bio::Factory::ObjectBuilderI compliant object
        Args    : [optional] a Bio::Factory::ObjectBuilderI compliant object

        Title   : location_factory
        Usage   : $seqio->location_factory($locfactory)
        Function: Get/Set the Bio::Factory::LocationFactoryI object to be used for
                  location string parsing
        Returns : a Bio::Factory::LocationFactoryI implementing object
        Args    : [optional] on set, a Bio::Factory::LocationFactoryI implementing