Mercurial > repos > xuebing > sharplab_seq_motif
diff mytools/sequence.py @ 0:39217fa39ff2
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| author | xuebing |
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| date | Tue, 13 Mar 2012 23:34:52 -0400 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/mytools/sequence.py Tue Mar 13 23:34:52 2012 -0400 @@ -0,0 +1,720 @@ +#!@WHICHPYTHON@ + +import copy, string, sys + +#------------------ Alphabet ------------------- + +class Alphabet(object): + """Biological alphabet class. + This defines the set of symbols from which various objects can be built, e.g. sequences and motifs. + The symbol set is immutable and accessed as a tuple. + symstr: symbols in alphabet as either a tuple or string + complement: dictionary defining letters and their complement + """ + def __init__(self, symstr, complement = None): + """Construct an alphabet from a string or tuple of characters. + Lower case characters will be converted to upper case. + An optional mapping for complements may be provided. + Example: + >>> alpha = sequence.Alphabet('ACGTttga', {'A':'C', 'G':'T'}) + >>> alpha.getSymbols() + will construct the DNA alphabet and output: + ('A', 'C', 'G', 'T') + """ + symlst = [] + for s in [str(sym).upper()[0] for sym in symstr]: + if not s in symlst: + symlst.append(s) + self.symbols = tuple(symlst) + if complement != None: + # expand the mapping and check for contradictions + cmap = {} + for s in self.symbols: + c = complement.get(s, None) + if c != None: + if s in cmap and cmap[s] != c: + raise RuntimeError("Alphabet complement map " + "contains contradictory mapping") + cmap[s] = c + cmap[c] = s + # replace mapping with indicies + cimap = {} + for idx in range (len(self.symbols)): + s = self.symbols[idx] + if s in cmap: + cimap[cmap[s]] = idx + # create tuple + cidxlst = [] + for idx in range (len(self.symbols)): + cidxlst.append(cimap.get(self.symbols[idx], None)) + self.complements = tuple(cidxlst) + else: + self.complements = None + + def getSymbols(self): + """Retrieve a tuple with all symbols, immutable membership and order""" + return self.symbols + + def getComplements(self): + """Retrieve a tuple with all complement indicies, immutable""" + return self.complements + + def isValidSymbol(self, sym): + """Check if the symbol is a member of alphabet""" + return any([s==sym for s in self.symbols]) + + def getIndex(self, sym): + """Retrieve the index of the symbol (immutable)""" + for idx in range (len(self.symbols)): + if self.symbols[idx] == sym: + return idx + raise RuntimeError("Symbol " + sym + " does not exist in alphabet") + + def isComplementable(self): + return self.complements != None + + def getComplement(self, sym): + """Retrieve the complement of the symbol (immutable)""" + return self.symbols[self.complements[self.getIndex(sym)]]; + + def isValidString(self, symstr): + """Check if the string contains only symbols that belong to the alphabet""" + found = True + for sym in symstr: + if self.isValidSymbol(sym) == False: + return False + return True + + def getLen(self): + """Retrieve the number of symbols in (the length of) the alphabet""" + return len(self.symbols) + +# pre-defined alphabets that can be specified by their name +predefAlphabets = [ + ("DNA" , Alphabet('ACGT', {'A':'T', 'G':'C'})), + ("RNA" , Alphabet('ACGU')), + ("Extended DNA" , Alphabet('ACGTYRN')), + ("Protein" , Alphabet('ACDEFGHIKLMNPQRSTVWY')), + ("Extended Protein" , Alphabet('ACDEFGHIKLMNPQRSTVWYX')), + ("TM Labels" , Alphabet('MIO')) +] + +def getAlphabet(name): + """Retrieve a pre-defined alphabet by name. + Currently, "Protein", "DNA", "RNA", "Extended DNA", "Extended Protein" and "TM Labels" are available. + Example: + >>> alpha = sequence.getAlphabet('Protein') + >>> alpha.getSymbols() + will retrieve the 20 amino acid alphabet and output the tuple: + ('A', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'K', 'L', 'M', 'N', 'P', 'Q', 'R', 'S', 'T', 'V', 'W', 'Y') + """ + for (xname, xalpha) in predefAlphabets: + if xname == name: + return xalpha + return None + +#------------------ Sequence ------------------- + +class Sequence(object): + """Biological sequence class. Sequence data is immutable. + + data: the sequence data as a tuple or string + alpha: the alphabet from which symbols are taken + name: the sequence name, if any + info: can contain additional sequence information apart from the name + """ + def __init__(self, sequence, alpha = None, name = "", seqinfo = ""): + """Create a sequence with sequence data. + Specifying the alphabet is optional, so is the name and info. + Example: + >>> myseq = sequence.Sequence('MVSAKKVPAIAMSFGVSF') + will create a sequence with name "", and assign one of the predefined alphabets on basis of what symbols were used. + >>> myseq.getAlphabet().getSymbols() + will most likely output the standard protein alphabet: + ('A', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'K', 'L', 'M', 'N', 'P', 'Q', 'R', 'S', 'T', 'V', 'W', 'Y') + """ + if type(sequence) is str: + self.data = tuple(sequence.upper()) + elif type(sequence) is tuple: + self.data = sequence + elif type(sequence) is list: + self.data = tuple([s.upper() for s in sequence]) + else: + raise RuntimeError("Sequence data is not specified correctly: must be string or tuple") + # Resolve choice of alphabet + validAlphabet = False + if alpha == None: # Alphabet is not set, attempt to set it automatically... + for (xname, xalpha) in predefAlphabets: # Iterate through each predefined alphabet, in order + if xalpha.isValidString( self.data ): # This alphabet works, go with it + self.alpha = alpha = xalpha + validAlphabet = True + break + self.name = name + self.info = seqinfo + if validAlphabet == False: # we were either unsuccessful above or the alphabet was specified so test it + if type(alpha) is str: # check if name is a predefined alphabet + for (xname, xalpha) in predefAlphabets: # Iterate through each predefined alphabet, check for name + if (xname == alpha): + alpha = xalpha + break + if type(alpha) is Alphabet: # the alphabet is specified + if alpha.isValidString(self.data) == False: + raise RuntimeError("Invalid alphabet specified: "+"".join(alpha.getSymbols())+" is not compatible with sequence '"+"".join(self.data)+"'") + else: + self.alpha = alpha + else: + raise RuntimeError("Could not identify alphabet from sequence") + + #basic getters and setters for the class + def getName(self): + """Get the name of the sequence""" + return self.name + def getInfo(self): + """Get additional info of the sequence (e.g. from the defline in a FASTA file)""" + return self.info + def getAlphabet(self): + """Retrieve the alphabet that is assigned to this sequence""" + return self.alpha + def setName(self, name): + """Change the name of the sequence""" + self.name = name + def setAlphabet(self, alpha): + """Set the alphabet, throws an exception if it is not compatible with the sequence data""" + if type(alpha) is Alphabet: + if alpha.isValid( sequence ) == False: + raise RuntimeError( "Invalid alphabet specified" ) + #sequence functions + def getSequence(self): + """Retrieve the sequence data (a tuple of symbols)""" + return self.data + def getString(self): + """Retrieve the sequence data as a string (copy of actual data)""" + return "".join(self.data) + def getLen(self): + """Get the length of the sequence (number of symbols)""" + return len(self.data) + def getSite(self, position, length = 1): + """Retrieve a site in the sequence of desired length. + Note that positions go from 0 to length-1, and that if the requested site + extends beyond those the method throws an exception. + """ + if position >= 0 and position <= self.getLen() - length: + if length == 1: + return self.data[position] + else: + return self.data[position:position+length] + else: + raise RuntimeError( "Attempt to access invalid position in sequence "+self.getName() ) + + def nice(self): + """ A short description of the sequence """ + print self.getName(), ":", self.getLen() + +def readStrings(filename): + """ Read one or more lines of text from a file--for example an alignment. + Return as a list of strings. + filename: name of file + """ + txtlist = [] + f = open(filename) + for line in f.readlines(): + txtlist.extend(line.split()) + return txtlist + +def readFASTA(filename, alpha = None): + """ Read one or more sequences from a file in FASTA format. + filename: name of file to load sequences from + alpha: alphabet that is used (if left unspecified, an attempt is made to identify the alphabet for each individual sequence) + """ + seqlist = [] + seqname = None + seqinfo = None + seqdata = [] + fh = open(filename) + thisline = fh.readline() + while (thisline): + if (thisline[0] == '>'): # new sequence + if (seqname): # take care of the data that is already in the buffer before processing the new sequence + try: + seqnew = Sequence(seqdata, alpha, seqname, seqinfo) + seqlist.append(seqnew) + except RuntimeError, e: + print >> sys.stderr, "Warning: "+seqname+" is invalid (ignored): ", e + seqinfo = thisline[1:-1] # everything on the defline is "info" + seqname = seqinfo.split()[0] # up to first space + seqdata = [] + else: # pull out the sequence data + cleanline = thisline.split() + for line in cleanline: + seqdata.extend(tuple(line.strip('*'))) # sometimes a line ends with an asterisk in FASTA files + thisline = fh.readline() + + if (seqname): + try: + seqnew = Sequence(seqdata, alpha, seqname, seqinfo) + seqlist.append(seqnew) + except RuntimeError, e: + print >> sys.stderr, "Warning: " + seqname + " is invalid (ignored): ", e + else: + raise RuntimeError("No sequences on FASTA format found in this file") + fh.close() + return seqlist + +def _writeOneFASTA(sequence, filehandle): + """Write one sequence in FASTA format to an already open file""" + filehandle.write(">" + sequence.getName()+"\n") + data = sequence.getSequence() + lines = ( sequence.getLen() - 1) / 60 + 1 + for i in range(lines): + #note: python lets us get the last line (var length) free + #lineofseq = data[i*60 : (i+1)*60] + "\n" + lineofseq = "".join(data[i*60 : (i+1)*60]) + "\n" + filehandle.write(lineofseq) + +def writeFASTA(sequence, filename): + """Write a list (or a single) of sequences to a file in the FASTA format""" + fh = open(filename, "w") + if isinstance(sequence, Sequence): + _writeOneFASTA(sequence, fh) + else: + for seq in sequence: + if isinstance(seq, Sequence): + _writeOneFASTA(seq, fh) + else: + print >> sys.stderr, "Warning: could not write " + seq.getName() + " (ignored)." + fh.flush() + fh.close() + +#------------------ Distrib ------------------- + +class Distrib(object): + """Class for storing a multinomial probability distribution over the symbols in an alphabet""" + def __init__(self, alpha, pseudo_count = 0.0): + self.alpha = alpha + self.tot = pseudo_count * self.alpha.getLen() + self.cnt = [pseudo_count for _ in range( self.alpha.getLen() )] + + def __deepcopy__(self, memo): + dup = Distrib(self.alpha) + dup.tot = copy.deepcopy(self.tot, memo) + dup.cnt = copy.deepcopy(self.cnt, memo) + return dup + + def count(self, syms = None ): + """Count an observation of a symbol""" + if syms == None: + syms = self.alpha.getSymbols() + for sym in syms: + idx = self.alpha.getIndex( sym ) + self.cnt[idx] += 1.0 + self.tot += 1 + + def complement(self): + """Complement the counts, throw an error if this is impossible""" + if not self.alpha.isComplementable(): + raise RuntimeError("Attempt to complement a Distrib " + "based on a non-complementable alphabet.") + coms = self.alpha.getComplements() + new_count = [] + for idx in range(len(coms)): + cidx = coms[idx] + if cidx == None: + cidx = idx + new_count.append(self.cnt[cidx]) + self.cnt = new_count + return self + + def reset(self): + """Reset the distribution, that is, restart counting.""" + self.tot = 0 + self.cnt = [0.0 for _ in range( self.alpha.getLen() )] + + def getFreq(self, sym = None): + """Determine the probability distribution from the current counts. + The order in which probabilities are given follow the order of the symbols in the alphabet.""" + if self.tot > 0: + if sym == None: + freq = tuple([ y / self.tot for y in self.cnt ]) + return freq + else: + idx = self.alpha.getIndex( sym ) + return self.cnt[idx] / self.tot + return None + + def pretty(self): + """Retrieve the probabilites for all symbols and return as a pretty table (a list of text strings)""" + table = ["".join(["%4s " % s for s in self.alpha.getSymbols()])] + table.append("".join(["%3.2f " % y for y in Distrib.getFreq(self)])) + return table + + def getSymbols(self): + """Get the symbols in the alphabet in the same order as probabilities are given.""" + return self.alpha.getSymbols() + + def getAlphabet(self): + """Get the alphabet over which the distribution is defined.""" + return self.alpha + +#------------------ Motif (and subclasses) ------------------- + +class Motif(object): + """ Sequence motif class--defining a pattern that can be searched in sequences. + This class is not intended for direct use. Instead use and develop sub-classes (see below). + """ + def __init__(self, alpha): + self.len = 0 + self.alpha = alpha + + def getLen(self): + """Get the length of the motif""" + return self.len + + def getAlphabet(self): + """Get the alphabet that is used in the motif""" + return self.alpha + + def isAlphabet(self, seqstr): + """Check if the sequence can be processed by this motif""" + mystr = seqstr + if type(seqstr) is Sequence: + mystr = seqstr.getString() + return self.getAlphabet().isValidString(mystr) + +import re + +class RegExp(Motif): + """A motif class that defines the pattern in terms of a regular expression""" + def __init__(self, alpha, re_string): + Motif.__init__(self, alpha) + self.pattern = re.compile(re_string) + + def match(self, seq): + """Find matches to the motif in a specified sequence. + The method is a generator, hence subsequent hits can be retrieved using next(). + The returned result is a tuple (position, match-sequence, score), where score is + always 1.0 since a regular expression is either true or false (not returned). + """ + myseq = seq + if not type(seq) is Sequence: + myseq = Sequence(seq, self.alpha) + mystr = myseq.getString() + if not Motif.isAlphabet(self, mystr): + raise RuntimeError("Motif alphabet is not valid for sequence " + myseq.getName()) + for m in re.finditer(self.pattern, mystr): + yield (m.start(), m.group(), 1.0) + +import math, time + +# Variables used by the PWM for creating an EPS file +_colour_def = ( + "/black [0 0 0] def\n" + "/red [0.8 0 0] def\n" + "/green [0 0.5 0] def\n" + "/blue [0 0 0.8] def\n" + "/yellow [1 1 0] def\n" + "/purple [0.8 0 0.8] def\n" + "/magenta [1.0 0 1.0] def\n" + "/cyan [0 1.0 1.0] def\n" + "/pink [1.0 0.8 0.8] def\n" + "/turquoise [0.2 0.9 0.8] def\n" + "/orange [1 0.7 0] def\n" + "/lightred [0.8 0.56 0.56] def\n" + "/lightgreen [0.35 0.5 0.35] def\n" + "/lightblue [0.56 0.56 0.8] def\n" + "/lightyellow [1 1 0.71] def\n" + "/lightpurple [0.8 0.56 0.8] def\n" + "/lightmagenta [1.0 0.7 1.0] def\n" + "/lightcyan [0.7 1.0 1.0] def\n" + "/lightpink [1.0 0.9 0.9] def\n" + "/lightturquoise [0.81 0.9 0.89] def\n" + "/lightorange [1 0.91 0.7] def\n") +_colour_dict = ( + "/fullColourDict <<\n" + " (G) orange\n" + " (T) green\n" + " (C) blue\n" + " (A) red\n" + " (U) green\n" + ">> def\n" + "/mutedColourDict <<\n" + " (G) lightorange\n" + " (T) lightgreen\n" + " (C) lightblue\n" + " (A) lightred\n" + " (U) lightgreen\n" + ">> def\n" + "/colorDict fullColourDict def\n") + +_eps_defaults = { + 'LOGOTYPE': 'NA', + 'FONTSIZE': '12', + 'TITLEFONTSIZE': '12', + 'SMALLFONTSIZE': '6', + 'TOPMARGIN': '0.9', + 'BOTTOMMARGIN': '0.9', + 'YAXIS': 'true', + 'YAXISLABEL': 'bits', + 'XAXISLABEL': '', + 'TITLE': '', + 'ERRORBARFRACTION': '1.0', + 'SHOWINGBOX': 'false', + 'BARBITS': '2.0', + 'TICBITS': '1', + 'COLORDEF': _colour_def, + 'COLORDICT': _colour_dict, + 'SHOWENDS': 'false', + 'NUMBERING': 'true', + 'OUTLINE': 'false', +} +class PWM(Motif): + """This motif subclass defines a pattern in terms of a position weight matrix. + An alphabet must be provided. A pseudo-count to be added to each count is + optional. A uniform background distribution is used by default. + """ + def __init__(self, alpha): + Motif.__init__(self, alpha) # set alphabet of this multinomial distribution + self.background = Distrib(alpha) # the default background ... + self.background.count(alpha.getSymbols()) # ... is uniform + self.nsites = 0 + + def setFromAlignment(self, aligned, pseudo_count = 0.0): + """Set the probabilities in the PWM from an alignment. + The alignment is a list of equal-length strings (see readStrings), OR + a list of Sequence. + """ + self.cols = -1 + self.nsites = len(aligned) + seqs = [] + # Below we create a list of Sequence from the alignment, + # while doing some error checking, and figure out the number of columns + for s in aligned: + # probably a text string, so we make a nameless sequence from it + if not type(s) is Sequence: + s=Sequence(s, Motif.getAlphabet(self)) + else: + # it was a sequence, so we check that the alphabet in + # this motif will be able to process it + if not Motif.isAlphabet(self, s): + raise RuntimeError("Motif alphabet is not valid for sequence " + s.getName()) + if self.cols == -1: + self.cols = s.getLen() + elif self.cols != s.getLen(): + raise RuntimeError("Sequences in alignment are not of equal length") + seqs.append(s) + # The line below initializes the list of Distrib (one for each column of the alignment) + self.counts = [Distrib(Motif.getAlphabet(self), pseudo_count) for _ in range(self.cols)] + # Next, we do the counting, column by column + for c in range( self.cols ): # iterate through columns + for s in seqs: # iterate through rows + # determine the index of the symbol we find at this position (row, column c) + self.counts[c].count(s.getSite(c)) + # Update the length + self.len = self.cols + + def reverseComplement(self): + """Reverse complement the PWM""" + i = 0 + j = len(self.counts)-1 + while (i < j): + temp = self.counts[i]; + self.counts[i] = self.counts[j] + self.counts[j] = temp + self.counts[i].complement() + self.counts[j].complement() + i += 1; + j -= 1; + if i == j: + self.counts[i].complement() + return self + + def getNSites(self): + """Get the number of sites that made the PWM""" + return self.nsites + + def setBackground(self, distrib): + """Set the background distribution""" + if not distrib.getAlphabet() == Motif.getAlphabet(self): + raise RuntimeError("Incompatible alphabets") + self.background = distrib + + def getFreq(self, col = None, sym = None): + """Get the probabilities for all positions in the PWM (a list of Distribs)""" + if (col == None): + return [y.getFreq() for y in self.counts] + else: + return self.counts[col].getFreq(sym) + + def pretty(self): + """Retrieve the probabilites for all positions in the PWM as a pretty table (a list of text strings)""" + #table = ["".join(["%8s " % s for s in self.alpha.getSymbols()])] + table = [] + for row in PWM.getFreq(self): + table.append("".join(["%8.6f " % y for y in row])) + return table + + def logoddsPretty(self, bkg): + """Retrieve the (base-2) log-odds for all positions in the PWM as a pretty table (a list of text strings)""" + table = [] + for row in PWM.getFreq(self): + #table.append("".join(["%8.6f " % (math.log((row[i]+1e-6)/bkg[i])/math.log(2)) for i in range(len(row))])) + table.append("".join(["%8.6f " % (math.log((row[i])/bkg[i])/math.log(2)) for i in range(len(row))])) + #table.append("".join(["%8.6f " % row[i] for i in range(len(row))])) + return table + + + def consensus_sequence(self): + """ + Get the consensus sequence corresponding to a PWM. + Consensus sequence is the letter in each column + with the highest probability. + """ + consensus = "" + alphabet = Motif.getAlphabet(self).getSymbols() + for pos in range(self.cols): + best_letter = alphabet[0] + best_p = self.counts[pos].getFreq(best_letter) + for letter in alphabet[1:]: + p = self.counts[pos].getFreq(letter) + if p > best_p: + best_p = p + best_letter = letter + consensus += best_letter + return consensus + + + def consensus(self): + """ + Get the consensus corresponding to a PWM. + Consensus at each column of motif is a list of + characters with non-zero probabilities. + """ + consensus = [] + for pos in range(self.cols): + matches = [] + for letter in Motif.getAlphabet(self).getSymbols(): + p = self.counts[pos].getFreq(letter) + if p > 0: + matches += letter + consensus.append(matches) + return consensus + + + def getScore(self, seq, start): + """Score this particular list of symbols using the PFM (background needs to be set separately)""" + sum = 0.0 + seqdata = seq.getSequence()[start : start+self.cols] + for pos in range(len(seqdata)): + q = self.counts[pos].getFreq(seqdata[pos]) + if q == 0: + q = 0.0001 # to avoid log(0) == -Infinity + logodds = math.log(q / self.background.getFreq(seqdata[pos])) + sum += logodds + return sum + + def match(self, seq, _LOG0 = -10): + """Find matches to the motif in a specified sequence. + The method is a generator, hence subsequent hits can be retrieved using next(). + The returned result is a tuple (position, match-sequence, score). + The optional parameter _LOG0 specifies a lower bound on reported logodds scores. + """ + myseq = seq + if not type(seq) is Sequence: + myseq = Sequence(seq, self.alpha) + if not Motif.isAlphabet(self, myseq): + raise RuntimeError("Motif alphabet is not valid for sequence " + myseq.getName()) + for pos in range(myseq.getLen() - self.cols): + score = PWM.getScore(self, myseq, pos) + if score > _LOG0: + yield (pos, "".join(myseq.getSite(pos, self.cols)), score) + + def writeEPS(self, program, template_file, eps_fh, + timestamp = time.localtime()): + """Write out a DNA motif to EPS format.""" + small_dfmt = "%d.%m.%Y %H:%M" + full_dfmt = "%d.%m.%Y %H:%M:%S %Z" + small_date = time.strftime(small_dfmt, timestamp) + full_date = time.strftime(full_dfmt, timestamp) + points_per_cm = 72.0 / 2.54 + height = 4.5 + width = self.getLen() * 0.8 + 2 + width = min(30, width) + points_height = int(height * points_per_cm) + points_width = int(width * points_per_cm) + defaults = _eps_defaults.copy() + defaults['CREATOR'] = program + defaults['CREATIONDATE'] = full_date + defaults['LOGOHEIGHT'] = str(height) + defaults['LOGOWIDTH'] = str(width) + defaults['FINEPRINT'] = program + ' ' + small_date + defaults['CHARSPERLINE'] = str(self.getLen()) + defaults['BOUNDINGHEIGHT'] = str(points_height) + defaults['BOUNDINGWIDTH'] = str(points_width) + defaults['LOGOLINEHEIGHT'] = str(height) + with open(template_file, 'r') as template_fh: + m_var = re.compile("\{\$([A-Z]+)\}") + for line in template_fh: + last = 0 + match = m_var.search(line) + while (match): + if (last < match.start()): + prev = line[last:match.start()] + eps_fh.write(prev) + key = match.group(1) + if (key == "DATA"): + eps_fh.write("\nStartLine\n") + for pos in range(self.getLen()): + eps_fh.write("({0:d}) startstack\n".format(pos+1)) + stack = [] + # calculate the stack information content + alpha_ic = 2 + h = 0 + for sym in self.getAlphabet().getSymbols(): + freq = self.getFreq(pos, sym) + if (freq == 0): + continue + h -= (freq * math.log(freq, 2)) + stack_ic = alpha_ic - h + # calculate the heights of each symbol + for sym in self.getAlphabet().getSymbols(): + freq = self.getFreq(pos, sym) + if (freq == 0): + continue + stack.append((freq * stack_ic, sym)) + stack.sort(); + # output the symbols + for symh, sym in stack: + eps_fh.write(" {0:f} ({1:s}) numchar\n".format( + symh, sym)) + eps_fh.write("endstack\n\n") + eps_fh.write("EndLine\n") + elif (key in defaults): + eps_fh.write(defaults[key]) + else: + raise RuntimeError('Unknown variable "' + key + + '" in EPS template') + last = match.end(); + match = m_var.search(line, last) + if (last < len(line)): + eps_fh.write(line[last:]) + + +#------------------ Main method ------------------- +# Executed if you run this file from the operating system prompt, e.g. +# > python sequence.py + +if __name__=='__main__': + alpha = getAlphabet('Extended DNA') + #seqs = readFASTA('pos.fasta') + seqs = [] + aln = readStrings('tmp0') + #regexp = RegExp(alpha, '[AG]G.[DE]TT[AS].') + pwm = PWM(alpha) + pwm.setFromAlignment(aln) + for row in pwm.pretty(): + print row + for s in seqs: + print s.getName(), s.getLen(), s.getAlphabet().getSymbols() + for m in regexp.match( s ): + print "pos: %d pat: %s %4.2f" % (m[0], m[1], m[2]) + for m in pwm.match( s ): + print "pos: %d pat: %s %4.2f" % (m[0], m[1], m[2])