Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Welcome To Ask or Share your Answers For Others

Categories

0 votes
571 views
in Technique[技术] by (71.8m points)

python - Regex Matching - A letter not preceded by another letter

What could be regex which match anystring followed by daily but it must not match daily preceded by m?

For example it should match following string

  • beta.daily
  • abcdaily
  • dailyabc
  • daily

But it must not match

  • mdaily or
  • abcmdaily or
  • mdailyabc

I have tried following and other regex but failed each time:

  • r'[^m]daily': But it doesn't match with daily
  • r'[^m]?daily' : It match with string containing mdaily which is not intended
See Question&Answers more detail:os

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
Welcome To Ask or Share your Answers For Others

1 Reply

0 votes
by (71.8m points)

Just add a negative lookbehind, (?<!m)d, before daily:

(?<!m)daily

The zero width negative lookbehind, (?<!m), makes sure daily is not preceded by m.

Demo


与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
OGeek|极客中国-欢迎来到极客的世界,一个免费开放的程序员编程交流平台!开放,进步,分享!让技术改变生活,让极客改变未来! Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Click Here to Ask a Question

1.4m articles

1.4m replys

5 comments

57.0k users

...