正则表达式提取子字符串python

Question

我正在尝试从一个精确的点提取一个子字符串，直到一个特殊的字符“，这是字符串：

element = '<div class="s-suggestion" data-alias="aps" data-crid="2AZHZA23OLYLF" data-isfb="false" data-issc="false" data-keyword="aa battery plus" data-nid="" data-reftag="nb_sb_ss_i_6_2" data-store="" data-type="a9" id="issDiv5"><span class="s-heavy"></span>ab<span class="s-heavy">reva cold sore treatment</span></div>'

我要提取的部分是关键字from：data-keyword =“till：the next”symbol，所以在这种情况下：aa battery plus

但是我只是得到了一封信，当用左边和右边用\\ b分隔符和方括号限制字符串时。

我试图使用re.findall（）方法

import re
element = '<div class="s-suggestion" data-alias="aps" data-crid="2AZHZA23OLYLF" data-isfb="false" data-issc="false" data-keyword="aa batteries plus" data-nid="" data-reftag="nb_sb_ss_i_6_2" data-store="" data-type="a9" id="issDiv5"><span class="s-heavy"></span>ab<span class="s-heavy">reva cold sore treatment</span></div>'
z = re.search(r'[\bdata-keyword="\b,'""']',element).group(0)
print(z)

这就是我得到的：

d
Process finished with exit code 0

我如何只提取关键字？ IE：aa电池加

Answer 1

如果您想要两个字符串之间的文本，您将需要使用此正则表达式格式。

import re

element = '<div class="s-suggestion" data-alias="aps" data-crid="2AZHZA23OLYLF" data-isfb="false" data-issc="false" data-keyword="aa batteries plus" data-nid="" data-reftag="nb_sb_ss_i_6_2" data-store="" data-type="a9" id="issDiv5"><span class="s-heavy"></span>ab<span class="s-heavy">reva cold sore treatment</span></div>'

z = re.search(r'data-keyword="(.*?)"', element).group(1)
print(z)

Answer 2

使用Regex解析HTML不是一个好主意。 相反，你可以使用像BeautifulSoup这样的html解析器。

例如：

from bs4 import BeautifulSoup

element = '<div class="s-suggestion" data-alias="aps" data-crid="2AZHZA23OLYLF" data-isfb="false" data-issc="false" data-keyword="aa battery plus" data-nid="" data-reftag="nb_sb_ss_i_6_2" data-store="" data-type="a9" id="issDiv5"><span class="s-heavy"></span>ab<span class="s-heavy">reva cold sore treatment</span></div>'
soup = BeautifulSoup(element, "html.parser")
print(soup.find("div", class_="s-suggestion")["data-keyword"])

输出：

aa battery plus

Answer 3

你不需要正则表达式。 您可以使用内置函数find(substring,begin,end)搜索'data-keyword'的索引。 然后搜索以下每个括号的索引，并对这些括号之间的文本进行切片。

i_key = element.find('data-keyword')
i_1 = element.find('"', i_key)
i_2 = element.find('"', i_1+1)
z = element[i_1+1:i_2]

有关查找功能的更多信息。

Answer 4

这个表达式可能在这里起作用，即使它可能不是最好的想法，我们可能想要使用这种方法来解决问题，但是如果我们必须：

data-keyword="\s*([^"]+?)\s*"

也可能在我们想要的数据之前和之后删除不需要的空格。

演示1

测试

# coding=utf8
# the above tag defines encoding for this document and is for Python 2.x compatibility

import re

regex = r"data-keyword=\"\s*([^\"]+?)\s*\""

test_str = ("<div class=\"s-suggestion\" data-alias=\"aps\" data-crid=\"2AZHZA23OLYLF\" data-isfb=\"false\" data-issc=\"false\" data-keyword=\"aa batteries plus\" data-nid=\"\" data-reftag=\"nb_sb_ss_i_6_2\" data-store=\"\" data-type=\"a9\" id=\"issDiv5\"><span class=\"s-heavy\"></span>ab<span class=\"s-heavy\">reva cold sore treatment</span></div>\n"
    "<div class=\"s-suggestion\" data-alias=\"aps\" data-crid=\"2AZHZA23OLYLF\" data-isfb=\"false\" data-issc=\"false\" data-keyword=\"    aa batteries plus     \" data-nid=\"\" data-reftag=\"nb_sb_ss_i_6_2\" data-store=\"\" data-type=\"a9\" id=\"issDiv5\"><span class=\"s-heavy\"></span>ab<span class=\"s-heavy\">reva cold sore treatment</span></div>")

matches = re.finditer(regex, test_str, re.MULTILINE)

for matchNum, match in enumerate(matches, start=1):

    print ("Match {matchNum} was found at {start}-{end}: {match}".format(matchNum = matchNum, start = match.start(), end = match.end(), match = match.group()))

    for groupNum in range(0, len(match.groups())):
        groupNum = groupNum + 1

        print ("Group {groupNum} found at {start}-{end}: {group}".format(groupNum = groupNum, start = match.start(groupNum), end = match.end(groupNum), group = match.group(groupNum)))

# Note: for Python 2.7 compatibility, use ur"" to prefix the regex and u"" to prefix the test string and substitution.

产量

Match 1 was found at 105-137: data-keyword="aa batteries plus"
Group 1 found at 119-136: aa batteries plus
Match 2 was found at 417-458: data-keyword="    aa batteries plus     "
Group 1 found at 435-452: aa batteries plus

RegEx电路

jex.im可视化正则表达式：

Answer 5

虽然我完全同意之前的回答，但您也可以考虑下一个解决方案：

element.split('data-keyword="')[-1].split('" data-nid')[0]

当您需要解析“结构化”输入时，这可能被认为非常方便...

Answer 6

你可以使用re.findall()函数：

import re
element = '<div class="s-suggestion" data-alias="aps" data-crid="2AZHZA23OLYLF" data-isfb="false" data-issc="false" data-keyword="aa battery plus" data-nid="" data-reftag="nb_sb_ss_i_6_2" data-store="" data-type="a9" id="issDiv5"><span class="s-heavy"></span>ab<span class="s-heavy">reva cold sore treatment</span></div>'
output = re.findall(r'data-keyword="(.*?)"', element)[0]
print(output)

产量

电池加