如何循环GraphML与LXML

Question

文件我有以下GraphML文件“mygraph.gml”，我想用一个简单的python脚本解析：

这代表了一个简单图2个节点“NODE0”，“节点1" 并把它们

<?xml version="1.0" encoding="UTF-8"?> 
<graphml xmlns="http://graphml.graphdrawing.org/xmlns" 
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
     xsi:schemaLocation="http://graphml.graphdrawing.org/xmlns 
     http://graphml.graphdrawing.org/xmlns/1.0/graphml.xsd"> 
    <key id="name" for="node" attr.name="name" attr.type="string"/> 
    <key id="weight" for="edge" attr.name="weight" attr.type="double"/> 
    <graph id="G" edgedefault="directed"> 
    <node id="n0"> 
     <data key="name">node1</data> 
    </node> 
    <node id="n1"> 
     <data key="name">node2</data> 
    </node> 
<edge source="n1" target="n0"> 
    <data key="weight">1</data> 
</edge> 
    </graph> 
</graphml> 

之间的边缘这代表具有两个节点N0和N1与权重1之间的边缘的曲线图。 我想用python解析这个结构。

我写了一个脚本LXML的帮助（我需要使用它，因为比这个简单的例子非常非常大的数据集，超过10^5个节点，蟒蛇minidom命名太慢）

import lxml.etree as et 

tree = et.parse('mygraph.gml') 

root = tree.getroot() 

graphml = { 
"graph": "{http://graphml.graphdrawing.org/xmlns}graph", 
"node": "{http://graphml.graphdrawing.org/xmlns}node", 
"edge": "{http://graphml.graphdrawing.org/xmlns}edge", 
"data": "{http://graphml.graphdrawing.org/xmlns}data", 
"label": "{http://graphml.graphdrawing.org/xmlns}data[@key='label']", 
"x": "{http://graphml.graphdrawing.org/xmlns}data[@key='x']", 
"y": "{http://graphml.graphdrawing.org/xmlns}data[@key='y']", 
"size": "{http://graphml.graphdrawing.org/xmlns}data[@key='size']", 
"r": "{http://graphml.graphdrawing.org/xmlns}data[@key='r']", 
"g": "{http://graphml.graphdrawing.org/xmlns}data[@key='g']", 
"b": "{http://graphml.graphdrawing.org/xmlns}data[@key='b']", 
"weight": "{http://graphml.graphdrawing.org/xmlns}data[@key='weight']", 
"edgeid": "{http://graphml.graphdrawing.org/xmlns}data[@key='edgeid']" 
} 

graph = tree.find(graphml.get("graph")) 
nodes = graph.findall(graphml.get("node")) 
edges = graph.findall(graphml.get("edge")) 

这个脚本得到正确的节点和边缘，使我可以在他们简单地重复

for n in nodes: 
    print n.attrib 

上边缘

或类似：

for e in edges: 
    print (e.attrib['source'], e.attrib['target']) 

但我无法真正理解如何获得边或节点的“数据”标签以打印边缘权重和节点标签“名称”。

这并没有为我工作：

weights = graph.findall(graphml.get("weight")) 

最后的名单始终是空的。为什么？我错过了一些东西，但不明白是什么。

Answer 1

你不能做一个合格，但发现每一个节点，你可以建立一个字典数据的键/值：

graph = tree.find(graphml.get("graph")) 
nodes = graph.findall(graphml.get("node")) 
edges = graph.findall(graphml.get("edge")) 

for node in nodes + edges: 
    attribs = {} 
    for data in node.findall(graphml.get('data')): 
     attribs[data.get('key')] = data.text 
    print 'Node', node, 'have', attribs 

它给出的结果：

Node <Element {http://graphml.graphdrawing.org/xmlns}node at 0x7ff053d3e5a0> have {'name': 'node1'} 
Node <Element {http://graphml.graphdrawing.org/xmlns}node at 0x7ff053d3e5f0> have {'name': 'node2'} 
Node <Element {http://graphml.graphdrawing.org/xmlns}edge at 0x7ff053d3e640> have {'weight': '1'}