如何在 R 中使用正则表达式替换 HTML 标签，而不使用替换函数？ [关闭]答案

<table class=MsoNormalTable border=0 cellspacing=0 cellpadding=0 width=513 style='width:385.0pt;margin-left:-.15pt;border-collapse:collapse'> <tr style='height:15.0pt'> <td width=411 nowrap style='width:308.0pt;border:solid windowtext 1.0pt;padding:0in 5.4pt 0in 5.4pt;height:15.0pt'>hdinka</td> <td width=103 nowrap valign=bottom style='width:77.0pt;border:solid windowtext 1.0pt;border-left:none;padding:0in 5.4pt 0in 5.4pt;height:15.0pt'>kya</td> </tr> <tr style='height:15.0pt'> <td width=411 nowrap style='width:308.0pt;border:solid windowtext 1.0pt;border-top:none;padding:0in 5.4pt 0in 5.4pt;height:15.0pt'>chika</td> <td width=103 nowrap valign=bottom style='width:77.0pt;border-top:none;border-left:none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;background:red;padding:0in 5.4pt 0in 5.4pt;height:15.0pt'>&nbsp</td> </tr> <tr style='height:15.0pt'> <td width=411 nowrap style='width:308.0pt;border:solid windowtext 1.0pt;border-top:none;padding:0in 5.4pt 0in 5.4pt;height:15.0pt'>pongal</td> <td width=103 nowrap valign=bottom style='width:77.0pt;border-top:none;border-left:none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;padding:0in 5.4pt 0in 5.4pt;height:15.0pt'>hawk</td> </tr> </table>

【解决方案1】：

你可以试试这样的 BeautifulSoup：

import re
from bs4 import BeautifulSoup

html="""<table class=MsoNormalTable border=0 cellspacing=0 cellpadding=0 width=513 style='width:385.0pt;margin-left:-.15pt;border-collapse:collapse'>
<tr style='height:15.0pt'>
<td width=411 nowrap style='width:308.0pt;border:solid windowtext 1.0pt;padding:0in 5.4pt 0in 5.4pt;height:15.0pt'>hdinka</td>
<td width=103 nowrap valign=bottom style='width:77.0pt;border:solid windowtext 1.0pt;border-left:none;padding:0in 5.4pt 0in 5.4pt;height:15.0pt'>kya</td>
</tr>
<tr style='height:15.0pt'>
<td width=411 nowrap style='width:308.0pt;border:solid windowtext 1.0pt;border-top:none;padding:0in 5.4pt 0in 5.4pt;height:15.0pt'>chika</td>
<td width=103 nowrap valign=bottom style='width:77.0pt;border-top:none;border-left:none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;background:red;padding:0in 5.4pt 0in 5.4pt;height:15.0pt'>&nbsp</td>
</tr>
<tr style='height:15.0pt'>
<td width=411 nowrap style='width:308.0pt;border:solid windowtext 1.0pt;border-top:none;padding:0in 5.4pt 0in 5.4pt;height:15.0pt'>pongal</td>
<td width=103 nowrap valign=bottom style='width:77.0pt;border-top:none;border-left:none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;padding:0in 5.4pt 0in 5.4pt;height:15.0pt'>hawk</td>
</tr>
</table>"""

soup=BeautifulSoup(html, 'html.parser')
for a in soup.find_all('td'):
    if 'background' in a.attrs['style']:
        b = re.findall(r'background:\w+', a.attrs['style'])
        a.attrs={}
        a.attrs['style'] = b[0]
    else:
        a.attrs={}
print soup

输出：

<table border="0" cellpadding="0" cellspacing="0" class="MsoNormalTable" style="width:385.0pt;margin-left:-.15pt;border-collapse:collapse" width="513">
<tr style="height:15.0pt">
<td>hdinka</td>
<td>kya</td>
</tr>
<tr style="height:15.0pt">
<td>chika</td>
<td style="background:red"> </td>
</tr>
<tr style="height:15.0pt">
<td>pongal</td>
<td>hawk</td>
</tr>
</table>

或者只使用没有 BeautifulSoup 的 re 模块，你可以这样做：

import re

res = re.sub(r'(<td)(?!.*background).*?(>)', r'\1\2', html)
res = re.sub(r'<td.*(background:\w+).*?>', r'<td style="\1">', res)
print res

输出：

<table class=MsoNormalTable border=0 cellspacing=0 cellpadding=0 width=513 style='width:385.0pt;margin-left:-.15pt;border-collapse:collapse'>
<tr style='height:15.0pt'>
<td>hdinka</td>
<td>kya</td>
</tr>
<tr style='height:15.0pt'>
<td>chika</td>
<td style="background:red">&nbsp</td>
</tr>
<tr style='height:15.0pt'>
<td>pongal</td>
<td>hawk</td>
</tr>
</table>

如果你想对所有标签都这样做，而不仅仅是<td>，你可以这样尝试：

res = re.sub(r'(<\w+)(?!.*background).*?(>)', r'\1\2', html)
res = re.sub(r'(<\w+).*(background:\w+).*?>', r'\1 style="\2">', res)
print res

输出：

<table>
<tr>
<td>hdinka</td>
<td>kya</td>
</tr>
<tr>
<td>chika</td>
<td style="background:red">&nbsp</td>
</tr>
<tr>
<td>pongal</td>
<td>hawk</td>
</tr>
</table>

【讨论】：