Regular Expressions 101

^start of line

Group 1((?:\d){1,3}(?:\.\d{1,3}){0,8})

Non-Capturing Group(?:\d){1,3}

{1,3}repeats the group contents below between 1 and 3 times:

\da digit

Non-Capturing Group(?:\.\d{1,3}){0,8}

{0,8}repeats the group contents below between 0 and 8 times:

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

\d{1,3}a digit, repeated between 1 and 3 times

Global pattern flags

m modifier: multiline. Causes ^ and $ to match the start and end of each line, not only the start and end of the string

g modifier: global. Finds all matches instead of stopping after the first

Detailed match information will be displayed here automatically.

Search reference

Regular Expression

^((?:\d){1,3}(?:\.\d{1,3}){0,8})

New

1 text
1.1 text 2
1.2 text 3
2 text 2
3 text 3
3.1 text 3.1
second string of 3.1
third string of 3.1
4.1.2.3.4.5
4.1.2.3.4.5.6.7.8


//I used .split() method to get multiline text from numbered list

Regular Expression

Substitution