Mercurial > repos > ulfschaefer > filter_vcf
comparison phe/variant_filters/QualFilter.py @ 0:834a312c0114 draft
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author | ulfschaefer |
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date | Thu, 10 Dec 2015 09:22:39 -0500 |
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-1:000000000000 | 0:834a312c0114 |
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1 '''Filter VCF on GQ parameter. | |
2 Created on 24 Sep 2015 | |
3 | |
4 @author: alex | |
5 ''' | |
6 | |
7 import argparse | |
8 import logging | |
9 | |
10 from phe.variant_filters import PHEFilterBase | |
11 | |
12 | |
13 class QualFilter(PHEFilterBase): | |
14 '''Filter sites by QUAL score.''' | |
15 | |
16 name = "LowSNPQual" | |
17 _default_threshold = 40.0 | |
18 parameter = "qual_score" | |
19 | |
20 @classmethod | |
21 def customize_parser(self, parser): | |
22 arg_name = self.parameter.replace("_", "-") | |
23 parser.add_argument("--%s" % arg_name, type=float, default=self._default_threshold, | |
24 help="Filter sites below given GQ score (default: %s)" % self._default_threshold) | |
25 | |
26 def __init__(self, args): | |
27 """Min Depth constructor.""" | |
28 # This needs to happen first, because threshold is initialised here. | |
29 super(QualFilter, self).__init__(args) | |
30 | |
31 # Change the threshold to custom gq value. | |
32 self.threshold = self._default_threshold | |
33 if isinstance(args, argparse.Namespace): | |
34 self.threshold = args.gq_score | |
35 elif isinstance(args, dict): | |
36 try: | |
37 self.threshold = float(args.get(self.parameter)) | |
38 except TypeError: | |
39 logging.error("Could not retrieve threshold from %s", args.get(self.parameter)) | |
40 self.threshold = None | |
41 | |
42 def __call__(self, record): | |
43 """Filter a :py:class:`vcf.model._Record`.""" | |
44 | |
45 | |
46 record_qual = record.QUAL | |
47 | |
48 if record_qual is None or record_qual < self.threshold: | |
49 # FIXME: when record_gq is None, i,e, error, what do you do? | |
50 return record_qual or False | |
51 else: | |
52 return None | |
53 | |
54 def short_desc(self): | |
55 short_desc = self.__doc__ or '' | |
56 | |
57 if short_desc: | |
58 short_desc = "%s (QUAL > %s)" % (short_desc, self.threshold) | |
59 | |
60 return short_desc |