my $parser = Bio::ASN1::Sequence->new('file' => "downloaded.asn1");
while(my $result = $parser->next_seq)
# extract data from $result, or Dumpvalue->new->dumpValue($result);
# a new way to get the $result data hash for a particular sequence id:
my $inx = Bio::ASN1::Sequence::Indexer->new(-filename => 'seq.idx');
my $seq = $inx->fetch_hash('AF093062');
# for creation of .idx index files please refer to
# Bio::ASN1::Sequence::Indexer perldoc
DESCRIPTIONBio::ASN1::Sequence is a regular expression-based Perl Parser for ASN.1-formatted NCBI sequences. It parses an ASN.1-formatted sequence record and returns a data structure that contains all data items from the sequence record.
The parser will report error & line number if input data does not conform to the NCBI Sequence annotation file format.
The sequence parser is basically a modified version of the high-performance Bio::ASN1::EntrezGene parser. However, I created a standalone module for sequence since it is more efficient to keep Sequence-specific code out of EntrezGene.pm.
In fact it is possible to provide reading of all NCBI's ASN.1-formatted files through simple variations of the Entrez Gene parser (I need more investigation to be sure, but at least the sequence parser works well).
Since demand for parsing NCBI ASN.1-formatted sequences is much lower than EntrezGene, this module is more like a beta version that works on the examples I checked, but I did not check all available records or data definitions. The error-reporting function of this module has to be useful sometimes. :)
Parameters: $maxerrstr (optional) - maximum number of characters after offending element, used by error reporting, default is 20 Example: $parser->maxerrstr(20); Function: get/set maxerrstr. Returns: maxerrstr. Notes:
Parameters: $filename for file that contains Sequence record(s) Example: $parser->input_file($filename); Function: Takes in name of a file containing Sequence records. opens the file and stores file handle Returns: none. Notes: Attempts to open file larger than 2 GB even on Perl that does not support 2 GB file (accomplished by calling "cat" and piping output. On OS that does not have "cat" error message will be displayed)
Parameters: maxerrstr => 20 (optional) - maximum number of characters after offending element, used by error reporting, default is 20 file or -file => $filename (optional) - name of the file to be parsed. call next_seq to parse! fh or -fh => $filehandle (optional) - handle of the file to be parsed. Example: my $parser = Bio::ASN1::Sequence->new(); Function: Instantiate a parser object Returns: Object reference Notes: Setting file or fh will reset line numbers etc. that are used for error reporting purposes, and seeking on file handle would mess up linenumbers!
Parameters: $string that contains Sequence record, $trimopt (optional) that specifies how the data structure returned should be trimmed. 2 is recommended and default $noreset (optional) that species that line number should not be reset DEPRECATED as external function!!! Do not call this function directly! Call next_seq() instead Example: my $value = $parser->parse($text); # DEPRECATED as # external function!!! Do not call this function # directly! Call next_seq() instead Function: Takes in a string representing Sequence record, parses the record and returns a data structure. Returns: A data structure containing all data items from the sequence record. Notes: DEPRECATED as external function!!! Do not call this function directly! Call next_seq() instead $string should not contain 'Seq-entry ::= set' at beginning!
Parameters: $trimopt (optional) that specifies how the data structure returned should be trimmed. option 2 is recommended and default Example: my $value = $parser->next_seq(); Function: Use the file handle generated by input_file, parses the next the record and returns a data structure. Returns: A data structure containing all data items from the sequence record. Notes: Must pass in a filename through new() or input_file() first! For details on how to use the $trimopt data trimming option please see comment for the trimdata method. An option of 2 is recommended and default The acceptable values for $trimopt include: 1 - trim as much as possibile 2 (or 0, undef) - trim to an easy-to-use structure 3 - no trimming (in version 1.06, prior to version 1.06, 0 or undef means no trimming)
Parameters: $hashref or $arrayref $trimflag (optional, see Notes) Example: trimdata($datahash); # using the default flag Function: recursively process all attributes of a hash/array hybrid and get rid of any arrayref that points to one-element arrays (trims data structure) depending on the optional flag. Returns: none - trimming happenes in-place Notes: This function is useful to compact a data structure produced by Bio::ASN1::Sequence::parse. The acceptable values for $trimopt include: 1 - trim as much as possibile 2 (or 0, undef) - trim to an easy-to-use structure 3 - no trimming (in version 1.06, prior to version 1.06, 0 or undef means no trimming) This function is duplicate to EntrezGene.pm's and code should be compressed in the future (using util module & subclass).
Parameters: $filehandle (optional) Example: trimdata($datahash); # using the default flag Function: getter/setter for file handle Returns: file handle for current file being parsed. Notes: Use with care! Line number report would not be corresponding to file's line number if seek operation is performed on the file handle!
Parameters: none Example: my $data = $parser->rawdata(); Function: Get the sequence data file that was just parsed Returns: a string containing the ASN1-formatted sequence record Notes: Must first parse a record then call this function! Could be useful in interpreting line number value in error report (if user did a seek on file handle right before parsing call)
_parseNCBI's Apr 05, 2005 format change forced much usage of lookahead, which would for sure slows parser down. But can't code efficiently without it.
INSTALLATIONBio::ASN1::Sequence is part of the Bio::ASN1::EntrezGene package. Bio::ASN1::EntrezGene package can be installed & tested as follows:
perl Makefile.PL make make test make install
CITATIONLiu, Mingyi, and Andrei Grigoriev. ``Fast parsers for Entrez Gene.'' Bioinformatics 21, no. 14 (2005): 3189-3190.
OPERATION SYSTEMS SUPPORTEDAny OS that Perl runs on.
Mailing listsUser 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
SupportPlease 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.
Reporting bugsReport 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:
AUTHORDr. Mingyi Liu <[email protected]>
COPYRIGHTThis software is copyright (c) 2005 by Mingyi Liu, 2005 by GPC Biotech AG, and 2005 by Altana Research Institute.
This software is available under the same terms as the perl 5 programming language system itself.