I need a Python regex matching the part of a string multiple times:

My String: aa-bbb-c-dd

I would like to have groups like this:

1. aa-bbb
2. bbb-c
3. c-dd

Does somebody have an idea on how to do this?

CodePudding user response：

You can use lookahead to get overlapping matches:

(?=\b([A-Za-z] -[A-Za-z] )\b)

See the regex demo.

Details:

• (?= - start of a positive lookahead that matches a location that is immediately followed with
  • \b - a word boundary
  • ([A-Za-z] -[A-Za-z] ) - Group 1: one or more ASCII letters, -, one or more ASCII letters
  • \b - a word boundary
• ) - end of the lookahead.

In Python, use it with re.findall:

import re
text = "aaaa-bb-ccc-dd"
print( re.findall(r'(?=\b([A-Z] -[A-Z] )\b)', text, re.I) )
# => ['aaaa-bb', 'bb-ccc', 'ccc-dd']

See the Python demo. Note I changed [A-Za-z] to [A-Z] in the code since I made the regex matching case insensitive with the help of the re.I option. Make sure you are using the r string literal prefix or \b will be treated as a BACKSPACE char, \x08, and not a word boundary.

Variations

• (?=\b([^\W\d_] -[^\W\d_] )\b) - matching any Unicode letters
• (?=(?<![^\W\d_])([^\W\d_] -[^\W\d_] )(?![^\W\d_])) - matching any Unicode letters and the boundaries are any non-letters