正则表达式到日期分割字段并保留 [英] Regex to splitstring on date and keep it

问题描述

我有一个字符串，我想在日期分割：

I have a string that I want to split on the date:

28/11/2016 Mushroom 05/12/2016 Carrot 12/12/2016 Broccoli 19/12/2016 Potato

应该最终作为

which should end up as

 28/11/2016 Mushroom
 05/12/2016 Carrot
 12/12/2016 Broccoli
 19/12/2016 Potato

显然日期变化很难。我已经制定了正则表达式，但我不知道如何保持分隔符（日期）。

Obviously the date changes which makes it difficult. I've worked out the regex but I can't figure out how to keep the delimiter (the date) as well.

import re

s = "28/11/2016 Mushroom 05/12/2016 Carrot 12/12/2016 Broccoli 19/12/2016 Potato"

replaced = re.sub(r"\d{2}\/\d{2}\/\d{4}\s*", ",", s) # looses data
print replaced

g = re.match(r"(\d{2}\/\d{2}\/\d{4}\s*)(.*)", s)

if g:
  # replaced = s.replace(group(0), "\n" + g.group(0)) # fails
  # print replaced 

推荐答案

如果总有空格，您可以使用分割方法在日期之间：

You may use a splitting approach if there is always whitespace between the dates:

\s+(?=\d+/\d+/\d+\s)

请参阅正则表达式演示

详细信息

Details:

• \s + - 匹配1+空格


• （？= \d + / \d + / \d + \s） - 后跟1位数字， / +一个或多个数字两次（类似日期的样式），然后是空格

• \s+ - match 1+ whitespaces
• (?=\d+/\d+/\d+\s) - that are followed with 1+ digits, and / + one or more digits twice (the date-like pattern), and then a whitespace

查看 Python演示以下：

import re
rx = r"\s+(?=\d+/\d+/\d+\s)"
s = "28/11/2016 Mushroom 05/12/2016 Carrot 12/12/2016 Broccoli 19/12/2016 Potato"
results = re.split(rx, s)
print(results)

或者，更复杂的正则表达式用于实际匹配这些日期：

Alternatively, a more complex regex can be used to actually match those dates:

\b\d+/\d+/\d+.*?(?=\s*\b\d+/\d+/\d+|$)

请参阅正则表达式演示和 Python演示：

import re
rx = r"\b\d+/\d+/\d+.*?(?=\b\d+/\d+/\d+|$)"
s = "28/11/2016 Mushroom 05/12/2016 Carrot 12/12/2016 Broccoli 19/12/2016 Potato"
results = re.findall(rx, s)
print(results)

这里，

• \b\d + / \d + / \d + - 匹配单词边界和类似日期的模式


• 。*？ - 任何0+字符，尽可能少到第一个位置跟随...


• （？= \s * \\ b \d + / \d + / \d + | $） - 0+个空格和类似日期的模式或字符串的结尾（ $ ）。

• \b\d+/\d+/\d+ - matches a word boundary and a date-like pattern
• .*? - any 0+ chars, as few as possible up to the first location that is followed with...
• (?=\s*\b\d+/\d+/\d+|$) - 0+ whitespaces and a date-like pattern OR the end of string ($).

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