Regular Expressions 101

Explanation

Pro

\ban ASCII word boundary

Positive Lookahead(?=[a-zA-Z]*[A-Z])

Character Class[a-zA-Z]*

*matches any number of characters from the set below:

a-zone character from a (97₁₀) to z (122₁₀) (case sensitive)

A-Zone character from A (65₁₀) to Z (90₁₀) (case sensitive)

Character Class[A-Z]

A-Zone character from A (65₁₀) to Z (90₁₀) (case sensitive)

Character Class[a-zA-Z]{1,4}

{1,4}matches between 1 and 4 characters from the set below:

a-zone character from a (97₁₀) to z (122₁₀) (case sensitive)

A-Zone character from A (65₁₀) to Z (90₁₀) (case sensitive)

\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

Detailed match information will be displayed here automatically.

25 tokens

\b(?=[a-zA-Z]*[A-Z])[a-zA-Z]{1,4}\b

New

A, Ab, AbC, ABC, Abcd, bACD, aBCd, abcD

Abcd and Hi but not abcd and not abcdefgHI

A, Ab, AbC, ABC, Abcd, bACD, aBCd, abcD

Abcd and Hi but not abcd and not abcdefgHI