[英]Reorder string using regular expressions
我想将第一次出现的日期或一般的正则表达式带到我的文本的开头:
例如: "I went out on 1 sep 2012 and it was better than 15 jan 2012"
,我希望得到"1 sep 2012, I went out on and it was better than 15 jan 2012"
我在想更换"1 sep 2012"
与",1 sep 2012,"
然后切割从字符串","
但我不知道该怎么写,而不是replace_with
:
line = re.sub(r'\d+\s(?:jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)\s\d{4}', 'replace_with', line, 1)
任何帮助?
使用捕获组 :
>>> import re
>>> s = "I went out on 1 sep 2012 and it was better than 15 jan 2012"
>>> r = re.compile('(^.*)(1 sep 2012 )(.*$)')
>>> r.sub(r'\2\1\3',s)
'1 sep 2012 I went out on and it was better than 15 jan 2012'
括号捕获字符串的一部分:
(^.*) # Capture everything from the start of the string
(1 sep 2012 ) # Upto the part we are interested in (captured)
(.*$) # Capture everything else
然后只需在替换`\\2\\1\\3'
注释中重新排序捕获组:要引用捕获组,需要一个原始字符串r'\\2\\1\\3'
。 我的例子中的第二组只是文字字符串(1 sep 2012 )
但当然这可以是任何正则表达式,例如你创建的那个(最后有一个额外的\\s
):
(\d+\s(?:jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)\s\d{4}\s)
>>> r = re.compile(r'(^.*)(\d+\s(?:aug|sep|oct|nov)\s\d{4}\s)(.*$)')
>>> r.sub(r'\2\1\3',s)
'1 sep 2012 I went out on and it was better than 15 jan 2012'
来自docs.python.org :
当存在'r'或'R'前缀时,字符串中包含反斜杠后面的字符而不进行更改。
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