Regular Expressions 101

Pro

Group 1(^|[^'$])

1st Alternative^

^start of line

2nd Alternative[^'$]

Negated Character Class[^'$]

'the literal ' (39₁₀ / 47₈ / 27₁₆)

$the literal $ (36₁₀ / 44₈ / 24₁₆)

\$the literal $ (36₁₀ / 44₈ / 24₁₆)

xthe literal x (120₁₀ / 170₈ / 78₁₆) (case sensitive)

Group 2([^']?)

Negated Character Class[^']?

?matches at most one character outside the set below:

'the literal ' (39₁₀ / 47₈ / 27₁₆)

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.

26 tokens

(^|[^'$])\$x([^']?)

New

$x books
1.Read $x books.
2.Read $$x is invalid.
3.Read$x books today.
4.Read books in $xminutes.
5.You selected '$x' as $x

$1$y$2

$x books
1.Read $x books.
2.Read $$x is invalid.
3.Read$x books today.
4.Read books in $xminutes.
5.You selected '$x' as $x