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Source code for galaxy.visualization.data_providers.phyloviz.nexusparser
import re
from .newickparser import Newick_Parser
MAX_READLINES = 200000
[docs]class Nexus_Parser(Newick_Parser):
[docs] def parseFile(self, filePath):
"""passes a file and extracts its Nexus content."""
return self.parseNexus(filePath)
[docs] def parseNexus(self, filename):
""" Nexus data is stored in blocks between a line starting with begin and another line starting with end;
Commends inside square brackets are to be ignored,
For more information: http://wiki.christophchamp.com/index.php/NEXUS_file_format
Nexus can store multiple trees
"""
with open(filename) as nex_file:
nexlines = nex_file.readlines()
rowCount = 0
inTreeBlock = False # sentinel to check if we are in a tree block
intranslateBlock = False # sentinel to check if we are in the translate region of the tree. Stores synonyms of the labellings
self.inCommentBlock = False
self.nameMapping = None # stores mapping representation used in nexus format
treeNames = []
for line in nexlines:
line = line.replace(";\n", "")
lline = line.lower()
if rowCount > MAX_READLINES or (not nex_file) :
break
rowCount += 1
# We are only interested in the tree block.
if "begin" in lline and "tree" in lline and not inTreeBlock:
inTreeBlock = True
continue
if inTreeBlock and "end" in lline[:3]:
inTreeBlock, currPhyloTree = False, None
continue
if inTreeBlock:
if "title" in lline: # Adding title to the tree
continue
if "translate" in lline:
intranslateBlock = True
self.nameMapping = {}
continue
if intranslateBlock:
mappingLine = self.splitLinebyWhitespaces(line)
key, value = mappingLine[1], mappingLine[2].replace(",", "").replace("'", "") # replacing illegal json characters
self.nameMapping[key] = value
# Extracting newick Trees
if "tree" in lline:
intranslateBlock = False
treeLineCols = self.splitLinebyWhitespaces(line)
treeName, newick = treeLineCols[2], treeLineCols[-1]
if newick == "": # Empty lines can be found in tree blocks
continue
currPhyloTree = self._parseNewickToJson(newick, treeName, nameMap=self.nameMapping)
self.phyloTrees.append(currPhyloTree)
treeIndex = len(self.phyloTrees) - 1
treeNames.append((treeName, treeIndex)) # appending name of tree, and its index
continue
return self.phyloTrees, treeNames
[docs] def splitLinebyWhitespaces(self, line):
"""replace tabs and write spaces to a single write space, so we can properly split it."""
return re.split(r"\s+", line)
[docs] def checkComments(self, line):
"""Check to see if the line/lines is a comment."""
if not self.inCommentBlock:
if "[" in line:
if "]" not in line:
self.inCommentBlock = True
else:
return "Nextline" # need to move on to the nextline after getting out of comment
else :
if "]" in line:
if line.rfind("[") > line.rfind("]"):
pass # a comment block is closed but another is open.
else:
self.inCommentBlock = False
return "Nextline" # need to move on to the nextline after getting out of comment
return ""