正则表达式匹配“ \\\\ r”

Question

I'm having trouble writing a regex that matches these inputs:
1. \\\\r
2. \\\\rSomeString
I need a regex that matches \\\\r

Answer 1

Escape the back slashes twice. String's interpret \\ as a special character marker.

Use \\\\\\\\r instead. \\\\ is actually interpreted as just \\ .

EDIT: So as per the comments you want any string that starts with \\\\r with any string after it. The regex pattern is as follows:

(\\\\r\S*)

\\\\\\\\r is the string you want at the start and \\S* says any non-white space ( \\S ) can come after any number of times ( * ).

Answer 2

A literal backslash in Python can be matched with r'\\\\' (note the use of the raw string literal!). You have two literal backslashes, thus, you need 4 backslashes (in a raw string literal) before r .

Since you may have any characters after \\\\r , you may use

import re
p = re.compile(r'\\\\r\S*')
test_str = r"\\r \\rtest"
print(p.findall(test_str))

See Python demo

Pattern description :

• \\\\\\\\ - 2 backslashes
• r - a literal r
• \\S* - zero or more non-whitespace characters.

Variations :

• If the characters after r can only be alphanumerics or underscore, use \\w* instead of \\S*
• If you want to only match \\\\r before non-word chars, add a \\B non-word boundary before the backslashes in the pattern.

Answer 3

您可以在线（例如在此站点）微调正则表达式 。