【2】文件读写-2-5-python读写vcf--pyvcf

做二代测序分析的时候，离不开vcf文件，因此对vcf中数据快速的提取以及整合，就显得尤为重要了，这里了解一下读取vcf的一个python包pyvcf

一、pyvcf介绍

官网： http://pyvcf.readthedocs.io/en/latest/INTRO.html

安装：

pip install pyvcf

读取数据：

>>> import vcf
>>> vcf_reader = vcf.Reader(open('vcf/test/example-4.0.vcf', 'r'))
>>> for record in vcf_reader:
...     print record
Record(CHROM=20, POS=14370, REF=G, ALT=[A])
Record(CHROM=20, POS=17330, REF=T, ALT=[A])
Record(CHROM=20, POS=1110696, REF=A, ALT=[G, T])
Record(CHROM=20, POS=1230237, REF=T, ALT=[None])
Record(CHROM=20, POS=1234567, REF=GTCT, ALT=[G, GTACT])


* ``Record.CHROM``
* ``Record.POS``
* ``Record.ID``
* ``Record.REF``
* ``Record.ALT``
* ``Record.QUAL``
* ``Record.FILTER``
* ``Record.INFO``

读取samples数据：

>>> record = next(vcf_reader)
>>> for sample in record.samples:
...     print sample['GT']
0|0
0|1
0/0
>>> print record.genotype('NA00001')['GT']
0|0


>>> call = record.genotype('NA00001')
>>> print call.site
Record(CHROM=20, POS=17330, REF=T, ALT=[A])
>>> print call.sample
NA00001
>>> print call.data
CallData(GT=0|0, GQ=49, DP=3, HQ=[58, 50])

>>> print call.called, call.gt_type, call.gt_bases, call.phased
True 0 T|T True

获得样本以及注释信息

>>> vcf_reader.metadata['fileDate']
'20090805'
>>> vcf_reader.samples
['NA00001', 'NA00002', 'NA00003']
>>> vcf_reader.filters
OrderedDict([('q10', Filter(id='q10', desc='Quality below 10')), ('s50', Filter(id='s50', desc='Less than 50% of samples have data'))])
>>> vcf_reader.infos['AA'].desc
'Ancestral Allele'