Regular Expressions 101

^start of line

\da digit

Group 1([-./ ]?)

Character Class[-./ ]?

?matches at most one character from the set below:

-the literal - (45₁₀ / 55₈ / 2D₁₆)

.the literal . (46₁₀ / 56₈ / 2E₁₆)

/the literal / (47₁₀ / 57₈ / 2F₁₆)

the literal (32₁₀ / 40₈ / 20₁₆)

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

\1the text saved by group 1

\d{4}a 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.

Search reference

Regular Expression

^\d\d([-./ ]?)\d{3}\1\d{4}$

New

55.635.8828
72/683/1582
86 942 7682
581827998

56.855/9856
56 4559428
52-355/9984