Regular Expressions 101

Negative Lookbehind(?<!y)

ythe literal y (121₁₀ / 171₈ / 79₁₆) (case sensitive)

yythe literal text yy (case sensitive)

Negative Lookahead(?!y)

ythe literal y (121₁₀ / 171₈ / 79₁₆) (case sensitive)

Global pattern flags

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

Detailed match information will be displayed here automatically.

Search reference

Regular Expression

(?<!y)yy(?!y)

New

y
yy
yyy
yyyy

mm/dd/yy
dd.mm.yy
mm/dd/yyyy
dd.mm.yyyy