如何使用BeautifulSoup查找评论标签？

Question

我尝试了soup.find（’！-‘），但似乎没有用。提前致谢。

编辑：感谢您有关如何查找所有评论的提示。我有一个后续问题。如何专门搜索评论？

例如，我有以下注释标记：

<!-- <span class="titlefont"> <i>Wednesday 110518</i>(05:00PM)<br /></span> -->

我真的只想要这些东西<i>Wednesday 110518</i>。“
110518”是我要用作搜索目标的日期YYMMDD。但是，我不知道如何在特定的注释标签中找到某些内容。

Answer 1

Pyparsing允许您使用内置htmlComment表达式搜索HTML注释，并附加解析时回调以验证和提取注释中的各种数据字段：

from pyparsing import makeHTMLTags, oneOf, withAttribute, Word, nums, Group, htmlComment
import calendar

# have pyparsing define tag start/end expressions for the 
# tags we want to look for inside the comments
span,spanEnd = makeHTMLTags("span")
i,iEnd = makeHTMLTags("i")

# only want spans with class=titlefont
span.addParseAction(withAttribute(**{'class':'titlefont'}))

# define what specifically we are looking for in this comment
weekdayname = oneOf(list(calendar.day_name))
integer = Word(nums)
dateExpr = Group(weekdayname("day") + integer("daynum"))
commentBody = '<!--' + span + i + dateExpr("date") + iEnd

# define a parse action to attach to the standard htmlComment expression,
# to extract only what we want (or raise a ParseException in case 
# this is not one of the comments we're looking for)
def grabCommentContents(tokens):
    return commentBody.parseString(tokens[0])
htmlComment.addParseAction(grabCommentContents)


# let's try it
htmlsource = """
want to match this one
<!-- <span class="titlefont"> <i>Wednesday 110518</i>(05:00PM)<br /></span> -->

don't want the next one, wrong span class
<!-- <span class="bodyfont"> <i>Wednesday 110519</i>(05:00PM)<br /></span> -->

not even a span tag!
<!-- some other text with a date in italics <i>Wednesday 110520</i>(05:00PM)<br /></span> -->

another matching comment, on a different day
<!-- <span class="titlefont"> <i>Thursday 110521</i>(05:00PM)<br /></span> -->
"""

for comment in htmlComment.searchString(htmlsource):
    parsedDate = comment.date
    # date info can be accessed like elements in a list
    print parsedDate[0], parsedDate[1]
    # because we named the expressions within the dateExpr Group
    # we can also get at them by name (this is much more robust, and 
    # easier to maintain/update later)
    print parsedDate.day
    print parsedDate.daynum
    print

印刷品：

Wednesday 110518
Wednesday
110518

Thursday 110521
Thursday
110521