Source Code for Module networkx.readwrite.leda

 1  """ 
 2  Read graphs in LEDA format. 
 3  See http://www.algorithmic-solutions.info/leda_guide/graphs/leda_native_graph_fileformat.html 
 4   
 5  """ 
 6  # Original author: D. Eppstein, UC Irvine, August 12, 2003. 
 7  # The original code at http://www.ics.uci.edu/~eppstein/PADS/ is public domain. 
 8  __author__ = """Aric Hagberg (hagberg@lanl.gov)""" 
 9  __date__ = """""" 
10  __credits__ = """""" 
11  __revision__ = "" 
12  #    Copyright (C) 2004-2007 by  
13  #    Aric Hagberg <hagberg@lanl.gov> 
14  #    Dan Schult <dschult@colgate.edu> 
15  #    Pieter Swart <swart@lanl.gov> 
16  #    Distributed under the terms of the GNU Lesser General Public License 
17  #    http://www.gnu.org/copyleft/lesser.html 
18   
19  import networkx 
20  from networkx.exception import NetworkXException, NetworkXError 
21  from networkx.utils import _get_fh, is_string_like 
22           
23 -def read_leda(path): 
24      """Read graph in GraphML format from path. 
25      Returns an XGraph or XDiGraph.""" 
26      fh=_get_fh(path,mode='r')         
27      G=parse_leda(fh) 
28      return G 
29           
30 -def parse_leda(lines): 
31      """Parse LEDA.GRAPH format from string or iterable. 
32      Returns an XGraph or XDiGraph.""" 
33      if is_string_like(lines): lines=iter(lines.split('\n')) 
34      lines = iter([line.rstrip('\n') for line in lines \ 
35              if not (line.startswith('#') or line.startswith('\n') or line=='')]) 
36      for i in range(3): 
37          lines.next() 
38      # Graph 
39      du = int(lines.next())      # -1 directed, -2 undirected 
40      if du==-1: 
41          G = networkx.XDiGraph() 
42      else: 
43          G = networkx.XGraph() 
44           
45      # Nodes 
46      n =int(lines.next())        # number of vertices 
47      node={} 
48      for i in range(1,n+1):  # LEDA counts from 1 to n 
49          symbol=lines.next()[2:-3]  # strip out data from |{data}| 
50          if symbol=="": symbol=str(i) # use int if no label - could be trouble 
51          node[i]=symbol 
52   
53      G.add_nodes_from([s for i,s in node.items()]) 
54           
55      # Edges 
56      m = int(lines.next())       # number of edges 
57      for i in range(m): 
58          try: 
59              s,t,reversal,label=lines.next().split() 
60          except: 
61              raise NetworkXError,\ 
62                    'Too few fields in LEDA.GRAPH edge %d' % (i+1) 
63          # BEWARE: no handling of reversal edges 
64          G.add_edge(node[int(s)],node[int(t)],label[2:-2]) 
65      return G 
66   
67   
68 -def _test_suite(): 
69      import doctest 
70      suite = doctest.DocFileSuite('tests/readwrite/leda.txt', 
71                                   package='networkx') 
72      return suite 
73   
74  if __name__ == "__main__": 
75      import os  
76      import sys 
77      import unittest 
78      if sys.version_info[:2] < (2, 4): 
79          print "Python version 2.4 or later required for tests (%d.%d detected)." %  sys.version_info[:2] 
80          sys.exit(-1) 
81      # directory of networkx package (relative to this) 
82      nxbase=sys.path[0]+os.sep+os.pardir 
83      sys.path.insert(0,nxbase) # prepend to search path 
84      unittest.TextTestRunner().run(_test_suite()) 
85