https://github.com/pysam-developers/pysam
Tip revision: 43c10664834cf3914000a744e6057826c6a6fa65 authored by John Marshall on 13 May 2024, 11:08:48 UTC
Increase test data creation idempotency
Increase test data creation idempotency
Tip revision: 43c1066
VCF.py.obsolete
#
# Code to read, write and edit VCF files
#
# VCF lines are encoded as a dictionary with these keys (note: all lowercase):
# 'chrom': string
# 'pos': integer
# 'id': string
# 'ref': string
# 'alt': list of strings
# 'qual': integer
# 'filter': None (missing value), or list of keys (strings); empty list parsed as ["PASS"]
# 'info': dictionary of values (see below)
# 'format': list of keys (strings)
# sample keys: dictionary of values (see below)
#
# The sample keys are accessible through vcf.getsamples()
#
# A dictionary of values contains value keys (defined in ##INFO or ##FORMAT lines) which map
# to a list, containign integers, floats, strings, or characters. Missing values are replaced
# by a particular value, often -1 or .
#
# Genotypes are not stored as a string, but as a list of 1 or 3 elements (for haploid and diploid samples),
# the first (and last) the integer representing an allele, and the second the separation character.
# Note that there is just one genotype per sample, but for consistency the single element is stored in a list.
#
# Header lines other than ##INFO, ##FORMAT and ##FILTER are stored as (key, value) pairs and are accessible
# through getheader()
#
# The VCF class can be instantiated with a 'regions' variable consisting of tuples (chrom,start,end) encoding
# 0-based half-open segments. Only variants with a position inside the segment will be parsed. A regions
# parser is available under parse_regions.
#
# When instantiated, a reference can be passed to the VCF class. This may be any class that supports a
# fetch(chrom, start, end) method.
#
#
#
# NOTE: the position that is returned to Python is 0-based, NOT 1-based as in the VCF file.
#
#
#
# TODO:
# only v4.0 writing is complete; alleles are not converted to v3.3 format
#
from collections import namedtuple, defaultdict
from operator import itemgetter
import sys, re, copy, bisect
import pysam
gtsRegEx = re.compile("[|/\\\\]")
alleleRegEx = re.compile('^[ACGTN]+$')
# Utility function. Uses 0-based coordinates
def get_sequence(chrom, start, end, fa):
# obtain sequence from .fa file, without truncation
if end<=start: return ""
if not fa: return "N"*(end-start)
if start<0: return "N"*(-start) + get_sequence(chrom, 0, end, fa).upper()
sequence = fa.fetch(chrom, start, end).upper()
if len(sequence) < end-start: sequence += "N"*(end-start-len(sequence))
return sequence
# Utility function. Parses a region string
def parse_regions( string ):
result = []
for r in string.split(','):
elts = r.split(':')
chrom, start, end = elts[0], 0, 3000000000
if len(elts)==1: pass
elif len(elts)==2:
if len(elts[1])>0:
ielts = elts[1].split('-')
if len(ielts) != 2: ValueError("Don't understand region string '%s'" % r)
try: start, end = int(ielts[0])-1, int(ielts[1])
except: raise ValueError("Don't understand region string '%s'" % r)
else:
raise ValueError("Don't understand region string '%s'" % r)
result.append( (chrom,start,end) )
return result
FORMAT = namedtuple('FORMAT','id numbertype number type description missingvalue')
###########################################################################################################
#
# New class
#
###########################################################################################################
class VCFRecord(object):
'''vcf record.
initialized from data and vcf meta
'''
data = None
vcf = None
def __init__(self, data, vcf):
self.data, self.vcf = data, vcf
if len(data) != len(self.vcf._samples):
self.error(str(data),
self.BAD_NUMBER_OF_COLUMNS,
"expected %s for %s samples (%s), got %s" % \
(len(self.vcf._samples),
len(self.vcf._samples),
self.vcf._samples,
len(data)))
property contig:
def __get__( self ): return self.data[0]
property pos:
def __get__( self ):
return self.data.pos
property id:
def __get__( self ): return self.data[2]
property ref:
def __get__(self ):
# note: gerton substitutes reference if it can be fixed.
return self.data[3].upper()
property alt:
def __get__(self):
# convert v3.3 to v4.0 alleles below
alt = self.data[4]
if alt == ".": alt = []
else: alt = alt.upper().split(',')
return alt
property qual:
def __get__(self):
qual = self.data[5]
if qual == ".": qual = -1
else:
try: qual = float(qual)
except: self.error(line,self.QUAL_NOT_NUMERICAL)
property filter:
def __get__(self):
# postpone checking that filters exist. Encode missing filter or no filtering as empty list
if cols[6] == "." or cols[6] == "PASS" or cols[6] == "0": filter = []
else: filter = cols[6].split(';')
return filter
property info:
def __get__(self):
col = self.data[7]
# dictionary of keys, and list of values
info = {}
if col != ".":
for blurp in col.split(';'):
elts = blurp.split('=')
if len(elts) == 1: v = None
elif len(elts) == 2: v = elts[1]
else: self.error(str(self.data),self.ERROR_INFO_STRING)
info[elts[0]] = self.parse_formatdata(elts[0], v, self.vcf._info, line)
return info
property format:
def __get__(self):
return self.data[8].split(':')
def __getitem__(self, key):
# parse sample columns
values = self.data[self.vcf._sample2column[key]].split(':')
alt = self.alt
format = self.format
if len(values) > len(format):
self.error(line,self.BAD_NUMBER_OF_VALUES,"(found %s values in element %s; expected %s)" % (len(values),sample,len(format)))
result = {}
for idx in range(len(format)):
expected = self.vcf.get_expected(format[idx], self.vcf._format, alt)
if idx < len(values): value = values[idx]
else:
if expected == -1: value = "."
else: value = ",".join(["."]*expected)
result[format[idx]] = self.vcf.parse_formatdata(format[idx], value, self.vcf._format, line)
if expected != -1 and len(result[format[idx]]) != expected:
self.error(str(self.data),self.BAD_NUMBER_OF_PARAMETERS,
"id=%s, expected %s parameters, got %s" % (format[idx],expected,result[format[idx]]))
if len(result[format[idx]] ) < expected: result[format[idx]] += [result[format[idx]][-1]]*(expected-len(result[format[idx]]))
result[format[idx]] = result[format[idx]][:expected]
return result
def __str__(self):
return str(self.data)
class VCF:
# types
NT_UNKNOWN = 0
NT_NUMBER = 1
NT_ALLELES = 2
NT_NR_ALLELES = 3
NT_GENOTYPES = 4
NT_PHASED_GENOTYPES = 5
_errors = { 0:"UNKNOWN_FORMAT_STRING:Unknown file format identifier",
1:"BADLY_FORMATTED_FORMAT_STRING:Formatting error in the format string",
2:"BADLY_FORMATTED_HEADING:Did not find 9 required headings (CHROM, POS, ..., FORMAT) %s",
3:"BAD_NUMBER_OF_COLUMNS:Wrong number of columns found (%s)",
4:"POS_NOT_NUMERICAL:Position column is not numerical",
5:"UNKNOWN_CHAR_IN_REF:Unknown character in reference field",
6:"V33_BAD_REF:Reference should be single-character in v3.3 VCF",
7:"V33_BAD_ALLELE:Cannot interpret allele for v3.3 VCF",
8:"POS_NOT_POSITIVE:Position field must be >0",
9:"QUAL_NOT_NUMERICAL:Quality field must be numerical, or '.'",
10:"ERROR_INFO_STRING:Error while parsing info field",
11:"ERROR_UNKNOWN_KEY:Unknown key (%s) found in formatted field (info; format; or filter)",
12:"ERROR_FORMAT_NOT_NUMERICAL:Expected integer or float in formatted field; got %s",
13:"ERROR_FORMAT_NOT_CHAR:Eexpected character in formatted field; got string",
14:"FILTER_NOT_DEFINED:Identifier (%s) in filter found which was not defined in header",
15:"FORMAT_NOT_DEFINED:Identifier (%s) in format found which was not defined in header",
16:"BAD_NUMBER_OF_VALUES:Found too many of values in sample column (%s)",
17:"BAD_NUMBER_OF_PARAMETERS:Found unexpected number of parameters (%s)",
18:"BAD_GENOTYPE:Cannot parse genotype (%s)",
19:"V40_BAD_ALLELE:Bad allele found for v4.0 VCF (%s)",
20:"MISSING_REF:Reference allele missing",
21:"V33_UNMATCHED_DELETION:Deleted sequence does not match reference (%s)",
22:"V40_MISSING_ANGLE_BRACKETS:Format definition is not deliminted by angular brackets",
23:"FORMAT_MISSING_QUOTES:Description field in format definition is not surrounded by quotes",
24:"V40_FORMAT_MUST_HAVE_NAMED_FIELDS:Fields in v4.0 VCF format definition must have named fields",
25:"HEADING_NOT_SEPARATED_BY_TABS:Heading line appears separated by spaces, not tabs",
26:"WRONG_REF:Wrong reference %s",
27:"ERROR_TRAILING_DATA:Numerical field ('%s') has semicolon-separated trailing data",
28:"BAD_CHR_TAG:Error calculating chr tag for %s",
29:"ZERO_LENGTH_ALLELE:Found zero-length allele",
30:"MISSING_INDEL_ALLELE_REF_BASE:Indel alleles must begin with single reference base"
}
# tag-value pairs; tags are not unique; does not include fileformat, INFO, FILTER or FORMAT fields
_header = []
# version number; 33=v3.3; 40=v4.0
_version = 40
# info, filter and format data
_info = {}
_filter = {}
_format = {}
# header; and required columns
_required = ["CHROM","POS","ID","REF","ALT","QUAL","FILTER","INFO","FORMAT"]
_samples = []
# control behaviour
_ignored_errors = set([11]) # ERROR_UNKNOWN_KEY
_warn_errors = set([])
_leftalign = False
# reference sequence
_reference = None
# regions to include; None includes everything
_regions = None
# statefull stuff
_lineno = -1
_line = None
_lines = None
def __init__(self, _copy=None, reference=None, regions=None, lines=None, leftalign=False):
# make error identifiers accessible by name
for id in self._errors.keys(): self.__dict__[self._errors[id].split(':')[0]] = id
if _copy != None:
self._leftalign = _copy._leftalign
self._header = _copy._header[:]
self._version = _copy._version
self._info = copy.deepcopy(_copy._info)
self._filter = copy.deepcopy(_copy._filter)
self._format = copy.deepcopy(_copy._format)
self._samples = _copy._samples[:]
self._sample2column = copy.deepcopy(_copy._sample2column)
self._ignored_errors = copy.deepcopy(_copy._ignored_errors)
self._warn_errors = copy.deepcopy(_copy._warn_errors)
self._reference = _copy._reference
self._regions = _copy._regions
if reference: self._reference = reference
if regions: self._regions = regions
if leftalign: self._leftalign = leftalign
self._lines = lines
def error(self,line,error,opt=None):
if error in self._ignored_errors: return
errorlabel, errorstring = self._errors[error].split(':')
if opt: errorstring = errorstring % opt
errwarn = ["Error","Warning"][error in self._warn_errors]
sys.stderr.write("Line %s: '%s'\n%s %s: %s\n" % (self._lineno,line,errwarn,errorlabel,errorstring))
if error in self._warn_errors: return
raise ValueError(errorstring)
def parse_format(self,line,format,filter=False):
if self._version >= 40:
if not format.startswith('<'):
self.error(line,self.V40_MISSING_ANGLE_BRACKETS)
format = "<"+format
if not format.endswith('>'):
self.error(line,self.V40_MISSING_ANGLE_BRACKETS)
format += ">"
format = format[1:-1]
data = {'id':None,'number':None,'type':None,'descr':None}
idx = 0
while len(format.strip())>0:
elts = format.strip().split(',')
first, rest = elts[0], ','.join(elts[1:])
if first.find('=') == -1 or (first.find('"')>=0 and first.find('=') > first.find('"')):
if self._version >= 40: self.error(line,self.V40_FORMAT_MUST_HAVE_NAMED_FIELDS)
if idx == 4: self.error(line,self.BADLY_FORMATTED_FORMAT_STRING)
first = ["ID=","Number=","Type=","Description="][idx] + first
if first.startswith('ID='): data['id'] = first.split('=')[1]
elif first.startswith('Number='): data['number'] = first.split('=')[1]
elif first.startswith('Type='): data['type'] = first.split('=')[1]
elif first.startswith('Description='):
elts = format.split('"')
if len(elts)<3:
self.error(line,self.FORMAT_MISSING_QUOTES)
elts = first.split('=') + [rest]
data['descr'] = elts[1]
rest = '"'.join(elts[2:])
if rest.startswith(','): rest = rest[1:]
else:
self.error(line,self.BADLY_FORMATTED_FORMAT_STRING)
format = rest
idx += 1
if filter and idx==1: idx=3 # skip number and type fields for FILTER format strings
if not data['id']: self.error(line,self.BADLY_FORMATTED_FORMAT_STRING)
if not data['descr']:
self.error(line,self.BADLY_FORMATTED_FORMAT_STRING)
data['descr'] = '<none>'
if not data['type'] and not data['number']:
# fine, ##filter format
return FORMAT(data['id'],self.NT_NUMBER,0,"Flag",data['descr'],'.')
if not data['type'] in ["Integer","Float","Character","String","Flag"]:
self.error(line,self.BADLY_FORMATTED_FORMAT_STRING)
# I would like a missing-value field, but it isn't there
if data['type'] in ['Integer','Float']: data['missing'] = None # Do NOT use arbitrary int/float as missing value
else: data['missing'] = '.'
if not data['number']: self.error(line,self.BADLY_FORMATTED_FORMAT_STRING)
try:
n = int(data['number'])
t = self.NT_NUMBER
except ValueError:
n = -1
if data['number'] == '.': t = self.NT_UNKNOWN
elif data['number'] == '#alleles': t = self.NT_ALLELES
elif data['number'] == '#nonref_alleles': t = self.NT_NR_ALLELES
elif data['number'] == '#genotypes': t = self.NT_GENOTYPES
elif data['number'] == '#phased_genotypes': t = self.NT_PHASED_GENOTYPES
else:
self.error(line,self.BADLY_FORMATTED_FORMAT_STRING)
return FORMAT(data['id'],t,n,data['type'],data['descr'],data['missing'])
def format_format( self, fmt, filter=False ):
values = [('ID',fmt.id)]
if fmt.number != None and not filter:
if fmt.numbertype == self.NT_UNKNOWN: nmb = "."
elif fmt.numbertype == self.NT_NUMBER: nmb = str(fmt.number)
elif fmt.numbertype == self.NT_ALLELES: nmb = "#alleles"
elif fmt.numbertype == self.NT_NR_ALLELES: nmb = "#nonref_alleles"
elif fmt.numbertype == self.NT_GENOTYPES: nmb = "#genotypes"
elif fmt.numbertype == self.NT_PHASED_GENOTYPES: nmb = "#phased_genotypes"
else:
raise ValueError("Unknown number type encountered: %s" % fmt.numbertype)
values.append( ('Number',nmb) )
values.append( ('Type', fmt.type) )
values.append( ('Description', '"' + fmt.description + '"') )
if self._version == 33:
format = ",".join(v for k,v in values)
else:
format = "<" + (",".join( "%s=%s" % (k,v) for (k,v) in values )) + ">"
return format
def get_expected(self, format, formatdict, alt):
fmt = formatdict[format]
if fmt.numbertype == self.NT_UNKNOWN: return -1
if fmt.numbertype == self.NT_NUMBER: return fmt.number
if fmt.numbertype == self.NT_ALLELES: return len(alt)+1
if fmt.numbertype == self.NT_NR_ALLELES: return len(alt)
if fmt.numbertype == self.NT_GENOTYPES: return ((len(alt)+1)*(len(alt)+2)) // 2
if fmt.numbertype == self.NT_PHASED_GENOTYPES: return (len(alt)+1)*(len(alt)+1)
return 0
def _add_definition(self, formatdict, key, data, line ):
if key in formatdict: return
self.error(line,self.ERROR_UNKNOWN_KEY,key)
if data == None:
formatdict[key] = FORMAT(key,self.NT_NUMBER,0,"Flag","(Undefined tag)",".")
return
if data == []: data = [""] # unsure what type -- say string
if type(data[0]) == type(0.0):
formatdict[key] = FORMAT(key,self.NT_UNKNOWN,-1,"Float","(Undefined tag)",None)
return
if type(data[0]) == type(0):
formatdict[key] = FORMAT(key,self.NT_UNKNOWN,-1,"Integer","(Undefined tag)",None)
return
formatdict[key] = FORMAT(key,self.NT_UNKNOWN,-1,"String","(Undefined tag)",".")
# todo: trim trailing missing values
def format_formatdata( self, data, format, key=True, value=True, separator=":" ):
output, sdata = [], []
if type(data) == type([]): # for FORMAT field, make data with dummy values
d = {}
for k in data: d[k] = []
data = d
# convert missing values; and silently add definitions if required
for k in data:
self._add_definition( format, k, data[k], "(output)" )
for idx,v in enumerate(data[k]):
if v == format[k].missingvalue: data[k][idx] = "."
# make sure GT comes first; and ensure fixed ordering; also convert GT data back to string
for k in data:
if k != 'GT': sdata.append( (k,data[k]) )
sdata.sort()
if 'GT' in data:
sdata = [('GT',map(self.convertGTback,data['GT']))] + sdata
for k,v in sdata:
if v == []: v = None
if key and value:
if v != None: output.append( k+"="+','.join(map(str,v)) )
else: output.append( k )
elif key: output.append(k)
elif value:
if v != None: output.append( ','.join(map(str,v)) )
else: output.append( "." ) # should not happen
# snip off trailing missing data
while len(output) > 1:
last = output[-1].replace(',','').replace('.','')
if len(last)>0: break
output = output[:-1]
return separator.join(output)
def enter_default_format(self):
for f in [FORMAT('GT',self.NT_NUMBER,1,'String','Genotype','.'),
FORMAT('GQ',self.NT_NUMBER,1,'Integer','Genotype Quality',-1),
FORMAT('DP',self.NT_NUMBER,1,'Integer','Read depth at this position for this sample',-1),
FORMAT('HQ',self.NT_UNKNOWN,-1,'Integer','Haplotype Quality',-1), # unknown number, since may be haploid
FORMAT('FT',self.NT_NUMBER,1,'String','Sample Genotype Filter','.')]:
if f.id not in self._format:
self._format[f.id] = f
def parse_header( self, line ):
assert line.startswith('##')
elts = line[2:].split('=')
key = elts[0].strip()
value = '='.join(elts[1:]).strip()
if key == "fileformat":
if value == "VCFv3.3":
self._version = 33
elif value == "VCFv4.0":
self._version = 40
elif value == "VCFv4.1":
self._version = 41
else:
self.error(line,self.UNKNOWN_FORMAT_STRING)
elif key == "INFO":
f = self.parse_format(line, value)
self._info[ f.id ] = f
elif key == "FILTER":
f = self.parse_format(line, value, filter=True)
self._filter[ f.id ] = f
elif key == "FORMAT":
f = self.parse_format(line, value)
self._format[ f.id ] = f
else:
# keep other keys in the header field
self._header.append( (key,value) )
def write_header( self, stream ):
stream.write("##fileformat=VCFv%s.%s\n" % (self._version // 10, self._version % 10))
for key,value in self._header: stream.write("##%s=%s\n" % (key,value))
for var,label in [(self._info,"INFO"),(self._filter,"FILTER"),(self._format,"FORMAT")]:
for f in var.itervalues(): stream.write("##%s=%s\n" % (label,self.format_format(f,filter=(label=="FILTER"))))
def parse_heading( self, line ):
assert line.startswith('#')
assert not line.startswith('##')
headings = line[1:].split('\t')
if len(headings)==1 and len(line[1:].split()) >= 9:
self.error(line,self.HEADING_NOT_SEPARATED_BY_TABS)
headings = line[1:].split()
for i,s in enumerate(self._required):
if len(headings)<=i or headings[i] != s:
if len(headings) <= i:
err = "(%sth entry not found)" % (i+1)
else:
err = "(found %s, expected %s)" % (headings[i],s)
#self.error(line,self.BADLY_FORMATTED_HEADING,err)
# allow FORMAT column to be absent
if len(headings) == 8:
headings.append("FORMAT")
else:
self.error(line,self.BADLY_FORMATTED_HEADING,err)
self._samples = headings[9:]
self._sample2column = dict( [(y,x) for x,y in enumerate( self._samples ) ] )
def write_heading( self, stream ):
stream.write("#" + "\t".join(self._required + self._samples) + "\n")
def convertGT(self, GTstring):
if GTstring == ".": return ["."]
try:
gts = gtsRegEx.split(GTstring)
if len(gts) == 1: return [int(gts[0])]
if len(gts) != 2: raise ValueError()
if gts[0] == "." and gts[1] == ".": return [gts[0],GTstring[len(gts[0]):-len(gts[1])],gts[1]]
return [int(gts[0]),GTstring[len(gts[0]):-len(gts[1])],int(gts[1])]
except ValueError:
self.error(self._line,self.BAD_GENOTYPE,GTstring)
return [".","|","."]
def convertGTback(self, GTdata):
return ''.join(map(str,GTdata))
def parse_formatdata( self, key, value, formatdict, line ):
# To do: check that the right number of values is present
f = formatdict.get(key,None)
if f == None:
self._add_definition(formatdict, key, value, line )
f = formatdict[key]
if f.type == "Flag":
if value is not None: self.error(line,self.ERROR_FLAG_HAS_VALUE)
return []
values = value.split(',')
# deal with trailing data in some early VCF files
if f.type in ["Float","Integer"] and len(values)>0 and values[-1].find(';') > -1:
self.error(line,self.ERROR_TRAILING_DATA,values[-1])
values[-1] = values[-1].split(';')[0]
if f.type == "Integer":
for idx,v in enumerate(values):
try:
if v == ".": values[idx] = f.missingvalue
else: values[idx] = int(v)
except:
self.error(line,self.ERROR_FORMAT_NOT_NUMERICAL,values)
return [0] * len(values)
return values
elif f.type == "String":
self._line = line
if f.id == "GT": values = map( self.convertGT, values )
return values
elif f.type == "Character":
for v in values:
if len(v) != 1: self.error(line,self.ERROR_FORMAT_NOT_CHAR)
return values
elif f.type == "Float":
for idx,v in enumerate(values):
if v == ".": values[idx] = f.missingvalue
try: return map(float,values)
except:
self.error(line,self.ERROR_FORMAT_NOT_NUMERICAL,values)
return [0.0] * len(values)
else:
# can't happen
self.error(line,self.ERROR_INFO_STRING)
def inregion(self, chrom, pos):
if not self._regions: return True
for r in self._regions:
if r[0] == chrom and r[1] <= pos < r[2]: return True
return False
def parse_data( self, line, lineparse=False ):
cols = line.split('\t')
if len(cols) != len(self._samples)+9:
# gracefully deal with absent FORMAT column
if len(cols) == 8 and len(self._samples)==0:
cols.append("")
else:
self.error(line,
self.BAD_NUMBER_OF_COLUMNS,
"expected %s for %s samples (%s), got %s" % (len(self._samples)+9, len(self._samples), self._samples, len(cols)))
chrom = cols[0]
# get 0-based position
try: pos = int(cols[1])-1
except: self.error(line,self.POS_NOT_NUMERICAL)
if pos < 0: self.error(line,self.POS_NOT_POSITIVE)
# implement filtering
if not self.inregion(chrom,pos): return None
# end of first-pass parse for sortedVCF
if lineparse: return chrom, pos, line
id = cols[2]
ref = cols[3].upper()
if ref == ".":
self.error(line,self.MISSING_REF)
if self._version == 33: ref = get_sequence(chrom,pos,pos+1,self._reference)
else: ref = ""
else:
for c in ref:
if c not in "ACGTN": self.error(line,self.UNKNOWN_CHAR_IN_REF)
if "N" in ref: ref = get_sequence(chrom,pos,pos+len(ref),self._reference)
# make sure reference is sane
if self._reference:
left = max(0,pos-100)
faref_leftflank = get_sequence(chrom,left,pos+len(ref),self._reference)
faref = faref_leftflank[pos-left:]
if faref != ref: self.error(line,self.WRONG_REF,"(reference is %s, VCF says %s)" % (faref,ref))
ref = faref
# convert v3.3 to v4.0 alleles below
if cols[4] == ".": alt = []
else: alt = cols[4].upper().split(',')
if cols[5] == ".": qual = -1
else:
try: qual = float(cols[5])
except: self.error(line,self.QUAL_NOT_NUMERICAL)
# postpone checking that filters exist. Encode missing filter or no filtering as empty list
if cols[6] == "." or cols[6] == "PASS" or cols[6] == "0": filter = []
else: filter = cols[6].split(';')
# dictionary of keys, and list of values
info = {}
if cols[7] != ".":
for blurp in cols[7].split(';'):
elts = blurp.split('=')
if len(elts) == 1: v = None
elif len(elts) == 2: v = elts[1]
else: self.error(line,self.ERROR_INFO_STRING)
info[elts[0]] = self.parse_formatdata(elts[0], v, self._info, line)
# Gracefully deal with absent FORMAT column
if cols[8] == "": format = []
else: format = cols[8].split(':')
# check: all filters are defined
for f in filter:
if f not in self._filter: self.error(line,self.FILTER_NOT_DEFINED, f)
# check: format fields are defined
for f in format:
if f not in self._format: self.error(line,self.FORMAT_NOT_DEFINED, f)
# convert v3.3 alleles
if self._version == 33:
if len(ref) != 1: self.error(line,self.V33_BAD_REF)
newalts = []
have_deletions = False
for a in alt:
if len(a) == 1: a = a + ref[1:] # SNP; add trailing reference
elif a.startswith('I'): a = ref[0] + a[1:] + ref[1:] # insertion just beyond pos; add first and trailing reference
elif a.startswith('D'): # allow D<seq> and D<num>
have_deletions = True
try:
l = int(a[1:]) # throws ValueError if sequence
if len(ref) < l: # add to reference if necessary
addns = get_sequence(chrom,pos+len(ref),pos+l,self._reference)
ref += addns
for i,na in enumerate(newalts): newalts[i] = na+addns
a = ref[l:] # new deletion, deleting pos...pos+l
except ValueError:
s = a[1:]
if len(ref) < len(s): # add Ns to reference if necessary
addns = get_sequence(chrom,pos+len(ref),pos+len(s),self._reference)
if not s.endswith(addns) and addns != 'N'*len(addns):
self.error(line,self.V33_UNMATCHED_DELETION,
"(deletion is %s, reference is %s)" % (a,get_sequence(chrom,pos,pos+len(s),self._reference)))
ref += addns
for i,na in enumerate(newalts): newalts[i] = na+addns
a = ref[len(s):] # new deletion, deleting from pos
else:
self.error(line,self.V33_BAD_ALLELE)
newalts.append(a)
alt = newalts
# deletion alleles exist, add dummy 1st reference allele, and account for leading base
if have_deletions:
if pos == 0:
# Petr Danacek's: we can't have a leading nucleotide at (1-based) position 1
addn = get_sequence(chrom,pos+len(ref),pos+len(ref)+1,self._reference)
ref += addn
alt = [allele+addn for allele in alt]
else:
addn = get_sequence(chrom,pos-1,pos,self._reference)
ref = addn + ref
alt = [addn + allele for allele in alt]
pos -= 1
else:
# format v4.0 -- just check for nucleotides
for allele in alt:
if not alleleRegEx.match(allele):
self.error(line,self.V40_BAD_ALLELE,allele)
# check for leading nucleotide in indel calls
for allele in alt:
if len(allele) != len(ref):
if len(allele) == 0: self.error(line,self.ZERO_LENGTH_ALLELE)
if ref[0].upper() != allele[0].upper() and "N" not in (ref[0]+allele[0]).upper():
self.error(line,self.MISSING_INDEL_ALLELE_REF_BASE)
# trim trailing bases in alleles
for i in range(1,min(len(ref),min(map(len,alt)))):
if len(set(allele[-1].upper() for allele in alt)) > 1 or ref[-1].upper() != alt[0][-1].upper():
break
ref, alt = ref[:-1], [allele[:-1] for allele in alt]
# left-align alleles, if a reference is available
if self._leftalign and self._reference:
while left < pos:
movable = True
for allele in alt:
if len(allele) > len(ref):
longest, shortest = allele, ref
else:
longest, shortest = ref, allele
if len(longest) == len(shortest) or longest[:len(shortest)].upper() != shortest.upper():
movable = False
if longest[-1].upper() != longest[len(shortest)-1].upper():
movable = False
if not movable:
break
ref = ref[:-1]
alt = [allele[:-1] for allele in alt]
if min(len(allele) for allele in alt) == 0 or len(ref) == 0:
ref = faref_leftflank[pos-left-1] + ref
alt = [faref_leftflank[pos-left-1] + allele for allele in alt]
pos -= 1
# parse sample columns
samples = []
for sample in cols[9:]:
dict = {}
values = sample.split(':')
if len(values) > len(format):
self.error(line,self.BAD_NUMBER_OF_VALUES,"(found %s values in element %s; expected %s)" % (len(values),sample,len(format)))
for idx in range(len(format)):
expected = self.get_expected(format[idx], self._format, alt)
if idx < len(values): value = values[idx]
else:
if expected == -1: value = "."
else: value = ",".join(["."]*expected)
dict[format[idx]] = self.parse_formatdata(format[idx], value, self._format, line)
if expected != -1 and len(dict[format[idx]]) != expected:
self.error(line,self.BAD_NUMBER_OF_PARAMETERS,
"id=%s, expected %s parameters, got %s" % (format[idx],expected,dict[format[idx]]))
if len(dict[format[idx]] ) < expected: dict[format[idx]] += [dict[format[idx]][-1]]*(expected-len(dict[format[idx]]))
dict[format[idx]] = dict[format[idx]][:expected]
samples.append( dict )
# done
d = {'chrom':chrom,
'pos':pos, # return 0-based position
'id':id,
'ref':ref,
'alt':alt,
'qual':qual,
'filter':filter,
'info':info,
'format':format}
for key,value in zip(self._samples,samples):
d[key] = value
return d
def write_data(self, stream, data):
required = ['chrom','pos','id','ref','alt','qual','filter','info','format'] + self._samples
for k in required:
if k not in data: raise ValueError("Required key %s not found in data" % str(k))
if data['alt'] == []: alt = "."
else: alt = ",".join(data['alt'])
if data['filter'] == None: filter = "."
elif data['filter'] == []:
if self._version == 33: filter = "0"
else: filter = "PASS"
else: filter = ';'.join(data['filter'])
if data['qual'] == -1: qual = "."
else: qual = str(data['qual'])
output = [data['chrom'],
str(data['pos']+1), # change to 1-based position
data['id'],
data['ref'],
alt,
qual,
filter,
self.format_formatdata( data['info'], self._info, separator=";" ),
self.format_formatdata( data['format'], self._format, value=False ) ]
for s in self._samples:
output.append( self.format_formatdata( data[s], self._format, key=False ) )
stream.write( "\t".join(output) + "\n" )
def _parse_header(self, stream):
self._lineno = 0
for line in stream:
self._lineno += 1
if line.startswith('##'):
self.parse_header( line.strip() )
elif line.startswith('#'):
self.parse_heading( line.strip() )
self.enter_default_format()
else:
break
return line
def _parse(self, line, stream):
if len(line.strip()) > 0:
d = self.parse_data( line.strip() )
if d: yield d
for line in stream:
self._lineno += 1
if self._lines and self._lineno > self._lines: raise StopIteration
d = self.parse_data( line.strip() )
if d: yield d
######################################################################################################
#
# API follows
#
######################################################################################################
def getsamples(self):
""" List of samples in VCF file """
return self._samples
def setsamples(self,samples):
""" List of samples in VCF file """
self._samples = samples
def getheader(self):
""" List of header key-value pairs (strings) """
return self._header
def setheader(self,header):
""" List of header key-value pairs (strings) """
self._header = header
def getinfo(self):
""" Dictionary of ##INFO tags, as VCF.FORMAT values """
return self._info
def setinfo(self,info):
""" Dictionary of ##INFO tags, as VCF.FORMAT values """
self._info = info
def getformat(self):
""" Dictionary of ##FORMAT tags, as VCF.FORMAT values """
return self._format
def setformat(self,format):
""" Dictionary of ##FORMAT tags, as VCF.FORMAT values """
self._format = format
def getfilter(self):
""" Dictionary of ##FILTER tags, as VCF.FORMAT values """
return self._filter
def setfilter(self,filter):
""" Dictionary of ##FILTER tags, as VCF.FORMAT values """
self._filter = filter
def setversion(self, version):
if version not in [33,40,41]: raise ValueError("Can only handle v3.3, v4.0 and v4.1 VCF files")
self._version = version
def setregions(self, regions):
self._regions = regions
def setreference(self, ref):
""" Provide a reference sequence; a Python class supporting a fetch(chromosome, start, end) method, e.g. PySam.FastaFile """
self._reference = ref
def ignoreerror(self, errorstring):
try: self._ignored_errors.add(self.__dict__[errorstring])
except KeyError: raise ValueError("Invalid error string: %s" % errorstring)
def warnerror(self, errorstring):
try: self._warn_errors.add(self.__dict__[errorstring])
except KeyError: raise ValueError("Invalid error string: %s" % errorstring)
def parse(self, stream):
""" Parse a stream of VCF-formatted lines. Initializes class instance and return generator """
last_line = self._parse_header(stream)
# now return a generator that does the actual work. In this way the pre-processing is done
# before the first piece of data is yielded
return self._parse(last_line, stream)
def write(self, stream, datagenerator):
""" Writes a VCF file to a stream, using a data generator (or list) """
self.write_header(stream)
self.write_heading(stream)
for data in datagenerator: self.write_data(stream,data)
def writeheader(self, stream):
""" Writes a VCF header """
self.write_header(stream)
self.write_heading(stream)
def compare_calls(self, pos1, ref1, alt1, pos2, ref2, alt2):
""" Utility function: compares two calls for equality """
# a variant should always be assigned to a unique position, one base before
# the leftmost position of the alignment gap. If this rule is implemented
# correctly, the two positions must be equal for the calls to be identical.
if pos1 != pos2: return False
# from both calls, trim rightmost bases when identical. Do this safely, i.e.
# only when the reference bases are not Ns
while len(ref1)>0 and len(alt1)>0 and ref1[-1] == alt1[-1]:
ref1 = ref1[:-1]
alt1 = alt1[:-1]
while len(ref2)>0 and len(alt2)>0 and ref2[-1] == alt2[-1]:
ref2 = ref2[:-1]
alt2 = alt2[:-1]
# now, the alternative alleles must be identical
return alt1 == alt2
###########################################################################################################
###########################################################################################################
## API functions added by Andreas
###########################################################################################################
def connect( self, filename ):
'''connect to tabix file.'''
self.tabixfile = pysam.Tabixfile( filename )
self._parse_header(self.tabixfile.header)
def fetch(self,
reference = None,
start = None,
end = None,
region = None ):
""" Parse a stream of VCF-formatted lines. Initializes class instance and return generator """
iter = self.tabixfile.fetch( reference, start, end, region, parser = pysam.asVCF() )
for x in iter:
yield VCFRecord( x, self )
def validate( self, record ):
'''validate vcf record.
returns a validated record.
'''
chrom, pos = record.chrom, record.pos
# check reference
ref = record.ref
if ref == ".":
self.error(str(record),self.MISSING_REF)
if self._version == 33: ref = get_sequence(chrom,pos,pos+1,self._reference)
else: ref = ""
else:
for c in ref:
if c not in "ACGTN": self.error(str(record),self.UNKNOWN_CHAR_IN_REF)
if "N" in ref: ref = get_sequence(chrom,
pos,
pos+len(ref),
self._reference)
# make sure reference is sane
if self._reference:
left = max(0,self.pos-100)
faref_leftflank = get_sequence(chrom,left,self.pos+len(ref),self._reference)
faref = faref_leftflank[pos-left:]
if faref != ref: self.error(line,self.WRONG_REF,"(reference is %s, VCF says %s)" % (faref,ref))
ref = faref
# check: format fields are defined
for f in record.format:
if f not in self._format: self.error(str(record),self.FORMAT_NOT_DEFINED, f)
# check: all filters are defined
for f in record.filter:
if f not in self._filter: self.error(str(record),self.FILTER_NOT_DEFINED, f)
# convert v3.3 alleles
if self._version == 33:
if len(ref) != 1: self.error(line,self.V33_BAD_REF)
newalts = []
have_deletions = False
for a in alt:
if len(a) == 1: a = a + ref[1:] # SNP; add trailing reference
elif a.startswith('I'): a = ref[0] + a[1:] + ref[1:] # insertion just beyond pos; add first and trailing reference
elif a.startswith('D'): # allow D<seq> and D<num>
have_deletions = True
try:
l = int(a[1:]) # throws ValueError if sequence
if len(ref) < l: # add to reference if necessary
addns = get_sequence(chrom,pos+len(ref),pos+l,self._reference)
ref += addns
for i,na in enumerate(newalts): newalts[i] = na+addns
a = ref[l:] # new deletion, deleting pos...pos+l
except ValueError:
s = a[1:]
if len(ref) < len(s): # add Ns to reference if necessary
addns = get_sequence(chrom,pos+len(ref),pos+len(s),self._reference)
if not s.endswith(addns) and addns != 'N'*len(addns):
self.error(line,self.V33_UNMATCHED_DELETION,
"(deletion is %s, reference is %s)" % (a,get_sequence(chrom,pos,pos+len(s),self._reference)))
ref += addns
for i,na in enumerate(newalts): newalts[i] = na+addns
a = ref[len(s):] # new deletion, deleting from pos
else:
self.error(line,self.V33_BAD_ALLELE)
newalts.append(a)
alt = newalts
# deletion alleles exist, add dummy 1st reference allele, and account for leading base
if have_deletions:
if pos == 0:
# Petr Danacek's: we can't have a leading nucleotide at (1-based) position 1
addn = get_sequence(chrom,pos+len(ref),pos+len(ref)+1,self._reference)
ref += addn
alt = [allele+addn for allele in alt]
else:
addn = get_sequence(chrom,pos-1,pos,self._reference)
ref = addn + ref
alt = [addn + allele for allele in alt]
pos -= 1
else:
# format v4.0 -- just check for nucleotides
for allele in alt:
if not alleleRegEx.match(allele):
self.error(line,self.V40_BAD_ALLELE,allele)
# check for leading nucleotide in indel calls
for allele in alt:
if len(allele) != len(ref):
if len(allele) == 0: self.error(line,self.ZERO_LENGTH_ALLELE)
if ref[0].upper() != allele[0].upper() and "N" not in (ref[0]+allele[0]).upper():
self.error(line,self.MISSING_INDEL_ALLELE_REF_BASE)
# trim trailing bases in alleles
for i in range(1,min(len(ref),min(map(len,alt)))):
if len(set(allele[-1].upper() for allele in alt)) > 1 or ref[-1].upper() != alt[0][-1].upper():
break
ref, alt = ref[:-1], [allele[:-1] for allele in alt]
# left-align alleles, if a reference is available
if self._leftalign and self._reference:
while left < pos:
movable = True
for allele in alt:
if len(allele) > len(ref):
longest, shortest = allele, ref
else:
longest, shortest = ref, allele
if len(longest) == len(shortest) or longest[:len(shortest)].upper() != shortest.upper():
movable = False
if longest[-1].upper() != longest[len(shortest)-1].upper():
movable = False
if not movable:
break
ref = ref[:-1]
alt = [allele[:-1] for allele in alt]
if min(len(allele) for allele in alt) == 0 or len(ref) == 0:
ref = faref_leftflank[pos-left-1] + ref
alt = [faref_leftflank[pos-left-1] + allele for allele in alt]
pos -= 1
