python - Python正则表达式找到两个组

Question

>>> text = '<a data-lecture-id="47"\n   data-modal-iframe="https://class.coursera.org/neuralnets-2012-001/lecture/view?lecture_id=47"\n   href="https://class.coursera.org/neuralnets-2012-001/lecture/47"\n   data-modal=".course-modal-frame"\n   rel="lecture-link"\n   class="lecture-link">\nAnother diversion: The softmax output function [7 min]</a>'

>>> import re
>>> re.findall(r'data-lecture-id="(\d+)"|(.*)</a>',a)
>>> [('47', ''), ('', 'Another diversion: The softmax output function [7 min]')]

我如何像这样提取数据：

>>> ['47', 'Another diversion: The softmax output function [7 min]']

我认为应该有一些更聪明的正则表达式。

Answer 1

不建议使用正则表达式解析 HTML。你可以试试这个xml.dom.minidom模块：

from xml.dom.minidom import parseString

xml = parseString('<a data-lecture-id="47"\n   data-modal-iframe="https://class.coursera.org/neuralnets-2012-001/lecture/view?lecture_id=47"\n   href="https://class.coursera.org/neuralnets-2012-001/lecture/47"\n   data-modal=".course-modal-frame"\n   rel="lecture-link"\n   class="lecture-link">\nAnother diversion: The softmax output function [7 min]</a>')
anchor = xml.getElementsByTagName("a")[0]
print anchor.getAttribute("data-lecture-id"), anchor.childNodes[0].data

Answer 2

你用itertools

import re
from itertools import chain, ifilter

raw_found = re.findall(r'data-lecture-id="(\d+)"|(.*)</a>', text)

# simple
found = [x for x in chain(*raw_found) if x]

# or faster
found = [x for x in ifilter(None, chain(*raw_found))]

# or more compact, also just as fast
found = list(ifilter(None, chain(*raw_found)))

print found

输出：

['47', 'Another diversion: The softmax output function [7 min]']

Answer 3

我自己找到了解决方案：

>>> re.findall('r'data-lecture-id="(\d+)"[\s\S]+>([\s\S]+)</a>',a)
>>> [('47', '\nAnother diversion: The softmax output function [7 min]')]

看起来更好，但仍然需要迭代它以提取一个简单的列表......