Regular Expressions 101

^start of line

Non-Capturing Group(?:\d{1,3}(?:\.\d{1,3}){0,2}(?:\.\d{0,3})?)?

?repeats the group contents below at most once:

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

Non-Capturing Group(?:\.\d{1,3}){0,2}

{0,2}repeats the group contents below between 0 and 2 times:

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

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

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

?repeats the group contents below at most once:

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

\d{0,3}a digit, repeated between 0 and 3 times

$end of line

Global pattern flags

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

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

Detailed match information will be displayed here automatically.

25 tokens

Regular Expression

^(?:\d{1,3}(?:\.\d{1,3}){0,2}(?:\.\d{0,3})?)?$

New

1.2.33..3
123.345.2.321
12
123.32.32
.