Regular Expressions 101

Pro

^start of line

Non-Capturing Group(?:\d{4}-\d{4}-\d{2}|\d{5}-(?:\d{3}-\d{2}|\d{4}-\d{1,2}))

1st Alternative\d{4}-\d{4}-\d{2}

\d{4}a Unicode decimal digit, repeated exactly 4 times

-the literal - (45₁₀ / 55₈ / 2D₁₆)

\d{4}a Unicode decimal digit, repeated exactly 4 times

-the literal - (45₁₀ / 55₈ / 2D₁₆)

\d{2}a Unicode decimal digit, repeated exactly 2 times

2nd Alternative\d{5}-(?:\d{3}-\d{2}|\d{4}-\d{1,2})

\d{5}a Unicode decimal digit, repeated exactly 5 times

-the literal - (45₁₀ / 55₈ / 2D₁₆)

Non-Capturing Group(?:\d{3}-\d{2}|\d{4}-\d{1,2})

1st Alternative\d{3}-\d{2}

\d{3}a Unicode decimal digit, repeated exactly 3 times

-the literal - (45₁₀ / 55₈ / 2D₁₆)

\d{2}a Unicode decimal digit, repeated exactly 2 times

2nd Alternative\d{4}-\d{1,2}

\d{4}a Unicode decimal digit, repeated exactly 4 times

-the literal - (45₁₀ / 55₈ / 2D₁₆)

\d{1,2}a Unicode decimal digit, repeated between 1 and 2 times

$end of line

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

^(?:\d{4}-\d{4}-\d{2}|\d{5}-(?:\d{3}-\d{2}|\d{4}-\d{1,2}))$

New

1234-1234-12
12345-123-12
12345-1234-1
12345-1234-12

1234-1234-12
12345-123-12
12345-1234-1
12345-1234-12