Question

我正在尝试从一个精确的点提取一个子字符串，直到一个特殊字符“，这是字符串：

import sys
from PyQt5 import QtCore, QtGui, QtWidgets, QtPrintSupport, QtWebEngineWidgets


class main(QtWebEngineWidgets.QWebEngineView):
    def __init__(self,windows,parent = None):
        super(main,self).__init__(parent)

        self._windows = windows
        self._windows.append(self)
        self.load(QtCore.QUrl("https://twitter.com/CodeRentor"))

    #Menu items on mouse Right click for Print 
    def contextMenuEvent(self, event):       
        cmenu = QtWidgets.QMenu(self)

        printAct = cmenu.addAction("print")
        action = cmenu.exec_(self.mapToGlobal(event.pos()))
        if action == printAct:
            self._preview()

    def createWindow(self, windows):
        if windows == QtWebEngineWidgets.QWebEnginePage.WebBrowserTab:
            webView = main(self._windows)
            webView.setAttribute(QtCore.Qt.WA_DeleteOnClose, True)
            webView.resize(900, 780) # <----
            webView.show()
            return webView
        elif windows == QtWebEngineWidgets.QWebEnginePage.WebDialog:
            webView = main(self._windows)
            webView.setAttribute(QtCore.Qt.WA_DeleteOnClose, True)
            webView.resize(900, 780) # <----
            webView.show()
            return webView
        return super(main, self).createWindow(windows)

    def _preview(self):
        dialog = QtPrintSupport.QPrintPreviewDialog()
        dialog.paintRequested.connect(self._request)
        dialog.exec_()
    def _request(self,printer):
        printer.newPage()
        painter = QtGui.QPainter()
        painter.begin(printer)
        screen = self.grab()
        painter.drawPixmap(0, 0, screen)
        painter.end()

if __name__ == "__main__":
    app = QtWidgets.QApplication(sys.argv)
    windows = []
    web = main(windows)
    web.show()
    sys.exit(app.exec_())

我要提取的部分是关键字，来自：data-keyword =“直到：下一个”符号，因此在这种情况下：aa battery plus

但是，只要用\ b分隔符和方括号限制左右字符串，我就得到一个字母。

我尝试使用re.findall（）方法

myDocument = QTextDocument()
myDocument.setHtml(self.currentHtml) # <= self.currentHtml is the current page converted to Html
font = QFont()
myDocument.setDefaultFont(font)
myDocument.defaultStyleSheet()
myDocument.setPageSize(QSizeF(printer.pageRect().size()))
myDocument.print_(printer)

这就是我得到的：

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>'

如何仅提取关键字？ IE：AA电池加

Answer 1

如果要在两个字符串之间输入文本，则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，您可以使用类似BeautifulSoup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

您不需要正则表达式。您可以使用内置函数find(substring,begin,end)来简单地搜索“数据关键字”的索引。然后搜索以下每个括号的索引，并将它们之间的文本切成薄片。

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find function的更多信息。

Answer 4

即使不是最好的想法，此表达式也可能在这里工作，我们可能想使用this method来解决问题，但是如果必须这样做：

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

还可以删除所需数据前后的多余空格。

Demo 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.

输出

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

虽然我完全同意上一个答案，但是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

您可以使用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)

输出

aa电池加

正则表达式提取子字符串python

6 个答案:

Demo 1

测试

输出

RegEx电路