Regular Expressions 101

Explanation
Pro

^start of line

\d+a Unicode decimal digit, repeated at least once

Group 1([\\/. -])

Character Class[\\/. -]

\\the literal \ (92₁₀ / 134₈ / 5C₁₆)

/the literal / (47₁₀ / 57₈ / 2F₁₆)

.the literal . (46₁₀ / 56₈ / 2E₁₆)

the literal (32₁₀ / 40₈ / 20₁₆)

-the literal - (45₁₀ / 55₈ / 2D₁₆)

Non-Capturing Group(?:\d+|[a-z]+)

1st Alternative\d+

\d+a Unicode decimal digit, repeated at least once

2nd Alternative[a-z]+

Character Class[a-z]+

+matches at least one character from the set below:

a-zone character from a (97₁₀) to z (122₁₀) (case sensitive)

\1the text saved by group 1

Group 2(\d{4})

\d{4}a Unicode decimal digit, repeated exactly 4 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+([\\/. -])(?:\d+|[a-z]+)\1(\d{4})$

New

2\06\1998
21.11.1998
18-02-2001
03/05/1999
20 july 1999