46 lines
1.3 KiB
Python
46 lines
1.3 KiB
Python
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from xml.etree.ElementTree import iterparse
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from urllib.request import urlopen
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# 在尤其关注节省内存时，牺牲运行速度，使用增量生成的方式读取XML文档
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def parse_and_remove(filename, path):
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# 将节点路径划分
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path_parts = path.split('/')
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# 通过迭代的方式解析XML文件
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doc = iterparse(filename, events=('start', 'end'))
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# 跳过根节点
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next(doc)
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# 设置存储栈
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tag_stack = []
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elem_stack = []
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for event, elem in doc:
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# iterparse会输出event和elem元组，表示状态和元素
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if event == 'start':
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# 如果检测状态是start就入栈
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tag_stack.append(elem.tag)
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elem_stack.append(elem)
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elif event == 'end':
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# 如果检测状态是end就出栈
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# print(tag_stack, path_parts)
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# 如果路径和需要寻找的标签相同，就生成并从栈中抹除
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if tag_stack == path_parts:
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yield elem
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elem_stack[-2].remove(elem)
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try:
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tag_stack.pop()
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elem_stack.pop()
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except IndexError:
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pass
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if __name__ == '__main__':
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u = urlopen('http://planet.python.org/rss20.xml')
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data = parse_and_remove(u, 'channel/item/title')
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# print(data)
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for d in data:
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print(d.text)
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