Regular Expressions 101

Positive Lookahead(?=^.{6,7}$)

^start of line

.{6,7}any character (except for line terminators), repeated between 6 and 7 times

$end of line

^start of line

Group 1(([0-9] ?){4}( ?[a-zA-Z]){2})

Group 2([0-9] ?){4}

{4}repeats the group contents below exactly 4 times:

Character Class[0-9]

0-9one character from 0 (48₁₀) to 9 (57₁₀)

?optionally matches the literal (32₁₀ / 40₈ / 20₁₆)

Group 3( ?[a-zA-Z]){2}

{2}repeats the group contents below exactly 2 times:

?optionally matches the literal (32₁₀ / 40₈ / 20₁₆)

Character Class[a-zA-Z]

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

A-Zone character from A (65₁₀) to Z (90₁₀) (case sensitive)

$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

(?=^.{6,7}$)^(([0-9] ?){4}( ?[a-zA-Z]){2})$

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