Question

我有句子。

text="The president of America is <PERSON>Barack Obama</PERSON>. He was born on August 4, 1961. Obama was reelected president in November 2012".

我想将<PERSON></PERSON>标记放入＆＃34;奥巴马＆＃34;，结果将是这样的：
The president of America is <PERSON>Barack Obama</PERSON>. He was born on August 4, 1961. <PERSON>Obama</PERSON> was reelected president in November 2012".

我想找到substring（例如：Obama）在子字符串之前没有标记<PERSON>，并且子字符串后面没有标记</PERSON>，但我不知道正确的python中正则表达式的语法 **我是python的新手：＆＃39;＆＃39;

使用简单的正则表达式re.sub(namedEntity, "<PERSON>"+namedEntity+"</PERSON>", text)将给出输出
The president of America is <PERSON>Barack <PERSON>Obama</PERSON></PERSON>. He was born on August 4, 1961. <PERSON>Obama</PERSON> was reelected president in November 2012".

这是我的代码（使用python2.7）

import re

result=re.sub(r"((?!<PERSON>).*"+namedEntity+".*(?!</PERSON>))","<PERSON>"+namedEntity+"</PERSON>",text)

print "result: "+result

输出
result: <PERSON>Obama</PERSON>
而且我不知道这是第一个＆＃34;奥巴马＆＃34;或者第二个。

感谢您的帮助

Answer 1

你非常接近。在您的新正则表达式r"((?!<PERSON>).*"+namedEntity+".*(?!</PERSON>))"中，您有.*之前和之后的匹配＆＃39;奥巴马＆＃39;使用之前和之后的任何字符，并且因为标签位于匹配的组中而忽略了外观。如果您删除它们，则会获得您之后的结果。

>>> import re
>>> text = "The president of America is <PERSON>Barack Obama</PERSON>. He was born on August 4, 1961. Obama was reelected president in November 2012"
>>> namedEntity = 'Obama'
>>> result = re.sub(r"((?!<PERSON>)"+namedEntity+"(?!</PERSON>))","<PERSON>"+namedEntity+"</PERSON>",text)
>>> print result
'The president of America is <PERSON>Barack Obama</PERSON>. He was born on August 4, 1961. <PERSON>Obama</PERSON> was reelected president in November 2012'

对于未来的正则表达式测试，regex101可以很好地检查在您实时更改它们时的工作方式。对于您的案例，this会显示正在发生的事情。

Answer 2

只需删除正则表达式中的.*部分。

>>>text="The president of America is <PERSON>Barack Obama</PERSON>. He was born on August 4, 1961. Obama was reelected president in November 2012"
>>> surname=re.search(r'<PERSON>(.*)</PERSON>', text).group(1).split()[1]
>>> print surname
Obama
>>> re.sub(r'(?<!<PERSON>)'+surname+'(?!</PERSON>)', '<PERSON>'+surname+'</PERSON>', text)'  
The president of America is <PERSON>Barack Obama</PERSON>. He was born on August 4, 1961. <PERSON>Obama</PERSON> was reelected president in November 2012'
>>>

注意：您还可以使用我在surname变量中捕获的正则表达式和捕获组来提取人的姓氏。你可以使用(?<!regex)来断言负面的后视和(?!regex)来断言负面的预测

如何用python中的正则表达式替换未包含在标记中的子字符串

2 个答案: