open1= testO.finditer(line) for m in open1: #print('opening:',m.group().replace('<', '').replace('>', '')) firstm= m.group().replace('<', '').replace('>', '').split() num = 0 for otherm in firstm: if num == 0: print('opening:',otherm) else: print('pram:',otherm) num+= 1 在正则表达式中，可以使用反向引用来指示匹配早期部分的子字符串,应再次出现正则表达式的。格式为\N（其中N为正整数），并返回到第N个匹配的文本正则表达式组。例如，正则表达式，如：r" (\w+) \1 仅当与组（\w+）完全匹配的字符串再次出现时才匹配 backref\1出现的位置。这可能与字符串“踢”匹配.例如，“the”出现两次。使用反向引用编写一个模式，当一行包含成对的open和关闭标签，例如在粗体中.
考虑到我们可能想要创建一个执行HTML剥离的脚本，即一个HTML文件，并返回一个纯文本文件，所有HTML标记都已从中删除出来这里我们不打算这样做，而是考虑一个更简单的例子，即删除我们在输入数据文件的任何行中找到的HTML标记。
import sys, re #------------------------------ # PART 1: # Key thing is to avoid matching strings that include # multiple tags, e.g. treating '' as a single # tag. Can do this in several ways. Firstly, use # non-greedy matching, so get shortest possible match # including the two angle brackets: tag = re.compile('') # The above treats the '/' of a close tag as a separate # optional component - so that this doesn't turn up as # part of the match '.group(1)', which is meant to return # the tag label. # Following alternative solution uses a negated character # class to explicitly prevent this including '>': tag = re.compile(']+)>') # Finally, following version separates finding the tag # label string from any (optional) parameters that might # also appear before the close angle bracket: tag = re.compile(r']+)?>') # Note that use of '\b' (as word boundary anchor) here means # we must mark the regex string as a 'raw' string (r'..'). #------------------------------ # PART 2: # Following closeTag definition requires first first char # after the open angle bracket to be '/', while openTag # definition excludes this by requiring first char to be # a 'word char' (\w): openTag = re.compile(r'<(\w[^>]*)>') closeTag = re.compile(r']*)>') # Following revised definitions are more carefully stated # for correct extraction of tag label (separately from # any parameters: openTag = re.compile(r'<(\w+\b)([^>]+)?>') closeTag = re.compile(r'') #------------------------------ # PART 3: # Above openTag definition will already get the string # encompassing any parameters, and return it as # m.group(2), i.e. defn: openTag = re.compile(r'<(\w+\b)([^>]+)?>') # If assume that parameters are continuous non-whitespace # chars separated by whitespace chars, then we can divide # them up using split - and that's how we handle them # here. (In reality, parameter strings can be a lot more # messy than this, but we won't try to deal with that.) #------------------------------ # PART 4: openCloseTagPair = re.compile(r'<(\w+\b)([^>]+)?>(.*?)') # Note use of non-greedy matching for the text falling # *between* the open/close tag pair - to avoid false # results where have two similar tag pairs on same line. #------------------------------ # PART 5: URLS # This is quite tricky. The URL expressions in the file # are of two kinds, of which the first is a string # between double quotes ("..") which may include # whitespace. For this case we might have a regex: url = re.compile('href=("[^">]+")', re.I) # The second case does not have quotes, and does not # allow whitespace, consisting of a continuous sequence # of non-whitespace material (that ends when you reach a # space or close bracket '>'). This might be: url = re.compile('href=([^">\s]+)', re.I) # We can combine these two cases as follows, and still # get the expression back as group(1): url = re.compile(r'href=("[^">]+"|[^">\s]+)', re.I) # Note that I've done nothing here to exclude 'mailto:' # links as being accepted as URLS. #------------------------------ with open('RGX_DATA.html') as infs: linenum = 0 for line in infs: linenum += 1 if line.strip() == '': continue print(' ', '-' * 100, '[%d]' % linenum, '\n TEXT:', line, end='') # PART 1: find HTML tags # (The following uses 'finditer' to find ALL matches # within the line) mm = tag.finditer(line) for m in mm: print('** TAG:', m.group(1), ' + [%s]' % m.group(2)) # PART 2,3: find open/close tags (+ params of open tags) mm = openTag.finditer(line) for m in mm: print('** OPENTAG:', m.group(1)) if m.group(2): for param in m.group(2).split(): print(' PARAM:', param) mm = closeTag.finditer(line) for m in mm: print('** CLOSETAG:', m.group(1)) # PART 4: find open/close tag pairs appearing on same line mm = openCloseTagPair.finditer(line) for m in mm: print("** PAIR [%s]: \"%s\"" % (m.group(1), m.group(3))) # PART 5: find URLs: mm = url.finditer(line) for m in mm: print('** URL:', m.group(1)) # PART 6: Strip out HTML tags (note that .sub will do all # possible substitutions, unless number is limited by count # keyword arg - which is fortunately what we want here) stripped = tag.sub('', line) print('** STRIPPED:', stripped, end = '')
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