Regular Expressions 101

Pro

^start of line

Non-Capturing Group(?: no \s)?

?repeats the group contents below at most once:

no the literal text no (case sensitive)

\sany whitespace character

Comment: not "no "

Group 1( # capture it (?: \S{1,2} \s )? # optional: 1-2 non whitespace characters and one space, BUT NOT GET "no " (it doesn't works) \S+ # non whitespace characters )

Comment: capture it

Non-Capturing Group(?: \S{1,2} \s )?

?repeats the group contents below at most once:

\S{1,2}any non-whitespace character, repeated between 1 and 2 times

\sany whitespace character

Comment: optional: 1-2 non whitespace characters and one space, BUT NOT GET "no " (it doesn't works)

\S+any non-whitespace character, repeated at least once

Comment: non whitespace characters

$end of line

Global pattern flags

g modifier: global. Finds all matches instead of stopping after the first

x modifier: extended. Ignores unescaped whitespace and comments outside character classes

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

^
  (?: no \s)? # not "no "
  ( # capture it
    (?: \S{1,2} \s )? # optional: 1-2 non whitespace characters and one space, BUT NOT GET "no " (it doesn't works)
    \S+ # non whitespace characters
  )
$

Regular Expression

Unit Tests