试图匹配重新

Question

我试图使用正则表达式打印它

trying = 'Mar 20th, 2009'

我不能在20号之后打印逗号，这是我试过的，

print (re.findall(r'(?:Jan|Feb|Mar|Apr|May|Jun|Jul|Aug|Sep|Oct|Nov|Dec)[a-z]*[\s]\d{2}[th , ]+', trying))
print (re.findall(r'(?:Jan|Feb|Mar|Apr|May|Jun|Jul|Aug|Sep|Oct|Nov|Dec)[a-z]*[\s]\d{2}[a-z,]+', trying))
print (re.findall(r'(?:Jan|Feb|Mar|Apr|May|Jun|Jul|Aug|Sep|Oct|Nov|Dec)[a-z]*[\s]\d{2}[a-z]+[,]', trying))

所需的输出应该是输入字符串。我究竟做错了什么？

Answer 1

这会奏效

>>> print (re.findall(r'(?:Jan|Feb|Mar|Apr|May|Jun|Jul|Aug|Sep|Oct|Nov|Dec)[\s]\d{1,2}th[,][\s]\d{4}',trying))
=> ['Mar 20th, 2009']`

现在让我们看看为什么你的试验没有给你预期的结果

1. print (re.findall(r'(?:Jan|Feb|Mar|Apr|May|Jun|Jul|Aug|Sep|Oct|Nov|Dec)[a-z]*[\s]\d{2}[th , ]+', trying)) - >这在th之后有空间所以它不匹配
2. print (re.findall(r'(?:Jan|Feb|Mar|Apr|May|Jun|Jul|Aug|Sep|Oct|Nov|Dec)[a-z]*[\s]\d{2}[a-z,]+', trying)) - >通过给+，你搜索结束找到一个或多个th,所以它只匹配到th,
3. print (re.findall(r'(?:Jan|Feb|Mar|Apr|May|Jun|Jul|Aug|Sep|Oct|Nov|Dec)[a-z]*[\s]\d{2}[a-z]+[,]', trying)) - >类似地，你搜索子字符串以,结束所以macthes直到th,

Answer 2

试试这个正则表达式

r'(?:Jan|Feb|Mar|Apr|May|Jun|Jul|Aug|Sep|Oct|Nov|Dec) (?:[0-9]{2}|[0-9])[rdth]{2}, \d{4}'

哪个会匹配这个，

>>> x = re.findall(r'(?:Jan|Feb|Mar|Apr|May|Jun|Jul|Aug|Sep|Oct|Nov|Dec) (?:[0-9]{2}|[0-9])[rdth]{2}, \d{4}', trying)
>>> x
['Mar 20th, 2009']
>>> tryig = 'Jun 3rd, 2017'
>>> x = re.findall(r'(?:Jan|Feb|Mar|Apr|May|Jun|Jul|Aug|Sep|Oct|Nov|Dec) (?:[0-9]{2}|[0-9])[rdth]{2}, \d{4}', tryig)
>>> x
['Jun 3rd, 2017']

根据评论更新：

>>> regex = r'(?:Jan|Feb|Mar|Apr|May|Jun|Jul|Aug|Sep|Oct|Nov|Dec) \d{1,2}[rdth]{2}, \d{4}'
>>> x = re.findall(regex, trying)
>>> x
['Mar 20th, 2009']