regex101: Python Match Workspace

Pro

Negative Lookbehind(?<![-\.\d])

Character Class[-\.\d]

-the literal - (45₁₀ / 55₈ / 2D₁₆)

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

\da Unicode decimal digit

Non-Capturing Group(?:0{0,2}?[0-9]\.|1\d?\d?\.|2[0-5]?[0-5]?\.){3}

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

1st Alternative0{0,2}?[0-9]\.

0{0,2}?the literal 0 (48₁₀ / 60₈ / 30₁₆) , repeated between 0 and 2 times

Character Class[0-9]

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

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

2nd Alternative1\d?\d?\.

1the literal 1 (49₁₀ / 61₈ / 31₁₆)

\d?optionally matches a Unicode decimal digit

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

3rd Alternative2[0-5]?[0-5]?\.

2the literal 2 (50₁₀ / 62₈ / 32₁₆)

Character Class[0-5]?

?matches at most one character from the set below:

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

Character Class[0-5]?

?matches at most one character from the set below:

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

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

Non-Capturing Group(?:0{0,2}?[0-9]|1\d?\d?|2[0-5]?[0-5]?)

1st Alternative0{0,2}?[0-9]

0{0,2}?the literal 0 (48₁₀ / 60₈ / 30₁₆) , repeated between 0 and 2 times

Character Class[0-9]

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

2nd Alternative1\d?\d?

1the literal 1 (49₁₀ / 61₈ / 31₁₆)

\d?optionally matches a Unicode decimal digit

3rd Alternative2[0-5]?[0-5]?

2the literal 2 (50₁₀ / 62₈ / 32₁₆)

Character Class[0-5]?

?matches at most one character from the set below:

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

Character Class[0-5]?

?matches at most one character from the set below:

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

Negative Lookahead(?![\.\d])

Character Class[\.\d]

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

\da Unicode decimal digit

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

25 tokens

Regular Expression

(?<![-\.\d])(?:0{0,2}?[0-9]\.|1\d?\d?\.|2[0-5]?[0-5]?\.){3}(?:0{0,2}?[0-9]|1\d?\d?|2[0-5]?[0-5]?)(?![\.\d])

New

str1 = 'Hello my name is Ben and my IP address is 256.0.0.0'
negative number is invalid: -127.2.1.2
valid: 001.001.001.001
str2 = 'Hello my name is Folks and my IP address is 1.2.3.4.5'
str3 = 'Hello all, ip addresses: 111.2.3., ip:0.0.0.0, 127.2.1.2'

Substitution

str1 = 'Hello my name is Ben and my IP address is 256.0.0.0'
negative number is invalid: -127.2.1.2
valid: 001.001.001.001
str2 = 'Hello my name is Folks and my IP address is 1.2.3.4.5'
str3 = 'Hello all, ip addresses: 111.2.3., ip:0.0.0.0, 127.2.1.2'