Regular Expressions 101

^start of line

Non-Capturing Group(?:(?:[0-9]|1[0-9]|2[0-4])(?:\.[0-9])?|25(?:\.)?)

1st Alternative(?:[0-9]|1[0-9]|2[0-4])(?:\.[0-9])?

Non-Capturing Group(?:[0-9]|1[0-9]|2[0-4])

1st Alternative[0-9]

Character Class[0-9]

0-9one character from 0 (48₁₀) to 9 (57₁₀)

2nd Alternative1[0-9]

1the literal 1 (49₁₀ / 61₈ / 31₁₆)

Character Class[0-9]

0-9one character from 0 (48₁₀) to 9 (57₁₀)

3rd Alternative2[0-4]

2the literal 2 (50₁₀ / 62₈ / 32₁₆)

Character Class[0-4]

0-4one character from 0 (48₁₀) to 4 (52₁₀)

Non-Capturing Group(?:\.[0-9])?

?repeats the group contents below at most once:

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

Character Class[0-9]

0-9one character from 0 (48₁₀) to 9 (57₁₀)

2nd Alternative25(?:\.)?

25the literal text 25

Non-Capturing Group(?:\.)?

?repeats the group contents below at most once:

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

$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.

Search reference

Regular Expression

^(?:(?:[0-9]|1[0-9]|2[0-4])(?:\.[0-9])?|25(?:\.)?)$

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