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On 07/17/2014 02:11 PM, Peter Cock wrote:
You could do something like that, and we already have Biopython packages in the ToolShed which can be listed as dependencies :)
If my module depends on the biopython from the toolshed, will that be accessible within a datatype? Would it be as simple as "from Bio import X"? Most of what I've seen of dependencies (and please forgive my lack of knowledge about them) consists of env.sh being sourced with paths to binaries, prior to tool run.
However, some things like GenBank are tricky - in order to tolerate NCBI dumps the Biopython parser will ignore any free text before the first LOCUS line. A confusing side effect is most text files are then treated as a GenBank file with zero records. But if it came back with some records it is probably OK :)
Interesting, very good to know.
Basically Biopython also does not care to offer file format detection simply because it is a can of worms.
Zen of Python - explicit is better than implicit.
We want you to tell us which format you want to try parsing it as.
Yes! Exactly! Which is why it's perfectly fine here:
SeqIO.parse( dataset.file_name, "genbank" )
All I want to know is whether or not this parses as a genbank file (and has 1 or more records). BioPython may not do automatic format detection (yuck, agreed), but since I already know I'm looking for a genbank file, simply being able to parse it or not is "good enough".
Peter (Speaking as the Bio.SeqIO maintainer for Biopython)
On Thu, Jul 17, 2014 at 7:45 PM, Eric Rasche firstname.lastname@example.org wrote: Let's pretend for a second that I'm rather lazy (oh...wait), and I have ZERO interest in writing datatype parsers to sniff and validate whether or not a specific file is a specific datatype. I'm a sysadmin and bioinformatician, and I've worked with dozens of libraries that exist to parse file formats, and they all die in flames when I feed them bad data.
Would it be possible to somehow define requirements for datatypes?
I don't want to take on the burden of code I write saying "yes, I've sniffed+validated this and it is absolutely a genbank file". That's a lot of responsibility, especially if people have malformed genbank files and their tools fail as a result.
I would like to do this with BioPython and turf the validation to another library that exists to parse genbank files, that will raise and exception if they're invalid.
def sniff(self, filename): from Bio import SeqIO try: self.records = list(SeqIO.parse( filename, "genbank" )) return True except: self.records = None return False
def validate(self, dataset): from Bio import SeqIO errors = list() try: self.records = list(SeqIO.parse( dataset.file_name, "genbank" )) except Exception, e: errors.append(e) return errors
def set_meta(self, dataset, **kwd): if self.records is not None: dataset.metadata.number_of_sequences = len(self.records)
so much easier! And I can shift the burden of validation and sniffing to upstream, rather than any failures being my fault and requiring maintenance of a complex sniffer.
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- -- Eric Rasche Programmer II Center for Phage Technology Texas A&M University College Station, TX 77843 404-692-2048 email@example.com firstname.lastname@example.org