Regular Expressions 101

Pro

\ban ASCII word boundary

Group 1(25[0-5]|2[0-4][0-9]|1[0-9]{2}|[1-9][0-9]|[0-9])

1st Alternative25[0-5]

25the literal text 25

Character Class[0-5]

0-5one character from 0 (48₁₀) to 5 (53₁₀)

2nd Alternative2[0-4][0-9]

2the literal 2 (50₁₀ / 62₈ / 32₁₆)

Character Class[0-4]

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

Character Class[0-9]

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

3rd Alternative1[0-9]{2}

1the literal 1 (49₁₀ / 61₈ / 31₁₆)

Character Class[0-9]{2}

{2}matches exactly 2 characters from the set below:

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

4th Alternative[1-9][0-9]

Character Class[1-9]

1-9one character from 1 (49₁₀) to 9 (57₁₀)

Character Class[0-9]

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

5th Alternative[0-9]

Character Class[0-9]

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

\ban ASCII word boundary

Group 2(\.\b(25[0-5]|2[0-4][0-9]|1[0-9]{2}|[1-9][0-9]|[0-9])\b){3}

{3}repeats the group contents below exactly 3 times:

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

\ban ASCII word boundary

Group 3(25[0-5]|2[0-4][0-9]|1[0-9]{2}|[1-9][0-9]|[0-9])

1st Alternative25[0-5]

25the literal text 25

Character Class[0-5]

0-5one character from 0 (48₁₀) to 5 (53₁₀)

2nd Alternative2[0-4][0-9]

2the literal 2 (50₁₀ / 62₈ / 32₁₆)

Character Class[0-4]

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

Character Class[0-9]

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

3rd Alternative1[0-9]{2}

1the literal 1 (49₁₀ / 61₈ / 31₁₆)

Character Class[0-9]{2}

{2}matches exactly 2 characters from the set below:

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

4th Alternative[1-9][0-9]

Character Class[1-9]

1-9one character from 1 (49₁₀) to 9 (57₁₀)

Character Class[0-9]

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

5th Alternative[0-9]

\ban ASCII word boundary

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

Ready to run

25 tokens

Regular Expression

\b(25[0-5]|2[0-4][0-9]|1[0-9]{2}|[1-9][0-9]|[0-9])\b(\.\b(25[0-5]|2[0-4][0-9]|1[0-9]{2}|[1-9][0-9]|[0-9])\b){3}

Regular Expression

Unit Tests