如何在字符串“ On x John write：”之后剥离所有内容

Question

I have a large string (coming from reading an email). Now when an user replies, a typical reply looks as follows:

"On x x x wrote:"

I would like to strip out all the text that comes after this pattern. However, I am not sure how to identify this pattern.

I know how to strip out everything after a certain word or character:

abc = abc.split('From:', 1)[0]

But what do you do when you have text in between the patterns On and wrote: ?

Sample:

\r\nOn Tue, Feb 12, 2019 at 1:11 PM +0100, "Name" <email@email.com<mailto:email@email.com>> wrote:\r\n

Answer 1

a regex will sort this:

re.match(r"\r\nOn.+wrote:", email)[0]

^ indicates start of string
On is the word "On"
.+ is one or more instances of anything
wrote: is the word "wrote"

the [0] at the end will get the first match from the email the email.strip() removes whitespace

example:

import re

email =  '\r\nOn Tue, Feb 12, 2019 at 1:11 PM +0100, "Name" <email@email.com<mailto:email@email.com>> wrote:\r\n'
extracted = re.match(r"On.+wrote:", email.replace('\r', '').replace('\n', ''))[0]
print(extracted)

Out[163]: 'On Tue, Feb 12, 2019 at 1:11 PM +0100, "Name" <email@email.com<mailto:email@email.com>> wrote:' 

an alternative to a regex, is to find the index of the first occurrence of the word "On", and the index of the word "wrote", and subset the whole text between those:

extracted = email[email.find('On'):email[email.find('On'):].find('wrote:')+8]

Answer 2

abc.split("on.*wrote:")[1]

https://regexr.com this is a great site to learn regex!

Answer 3

You can use a regex, and then when you have the exact match can split it. You can use /On/regex/From:/, where regex is a regular expression to detect "xxx".

More info can be found in the docs: enter link description here

Answer 4

您可以使用以下正则表达式查找模式：

 /(?:On\ x\ x\ x\ wrote\:)/