Regular Expressions 101

Explanation

Pro

(?i)applies the following effective flags to the remainder of the pattern: gmi

i modifier: insensitive. Matches without distinguishing uppercase and lowercase letters

Positive Lookahead(?=(@to(-|\s|)+do))

Group 1(@to(-|\s|)+do)

@tothe literal text @to (case insensitive)

Group 2(-|\s|)+

+repeats the group contents below at least once:

1st Alternative-

-the literal - (45₁₀ / 55₈ / 2D₁₆)

2nd Alternative\s

\sany whitespace character

3rd Alternative — matches an empty string

dothe literal text do (case insensitive)

(?-i)applies the following effective flags to the remainder of the pattern: gm

i modifier: -insensitive. Case-sensitive match

Negative Lookahead(?!@todo\s\w)

@todothe literal text @todo (case sensitive)

\sany whitespace character

\wany word character

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

Match Information

Detailed match information will be displayed here automatically.

Quick Reference

25 tokens

Regular Expression

(?i)(?=(@to(-|\s|)+do))(?-i)(?!@todo\s\w)

New

@todo Something
@to-do Something
@TODO Something
@ToDo Something
@TO-DO Something
@TO do Something
@to    do Something
@todo: Something
@todo : Something
@todo - Something