How to extract string with one regex?

Question

I need some help with regex. I have 3 types of headings

• 1.1.1.1 Abc
• B.1.1.1 Abc
• B. Abc

And I want to select like to select them like this

• 1.1.1.1
• B.1.1.1
• B

Thank you

Answer 1

Try this regex:

^[0-9\.A-Z\/]*?(?=\.?\s)