Regular Expressions 101

Pro

1st Alternative(?<=[A-Z])(\.)(?=[A-Z])

Positive Lookbehind(?<=[A-Z])

Character Class[A-Z]

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

Group 1(\.)

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

Positive Lookahead(?=[A-Z])

Character Class[A-Z]

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

2nd Alternative\.

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

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

(?<=[A-Z])(\.)(?=[A-Z])|\.

New

U.S.A is abbr  x.y  is not. But I.I.T. is also valid ABBVR and so is M.Tech, X.2, X., X.*