Regular Expressions 101

Pro

^start of line

Group 1([a-z])

Character Class[a-z]

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

Negative Lookahead(?!\1)

\1the text saved by group 1

Group 2([a-z])

Character Class[a-z]

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

Negative Lookahead(?!\1|\2)

1st Alternative\1

\1the text saved by group 1

2nd Alternative\2

\2the text saved by group 2

Character Class[a-z]

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

Non-Capturing Group(?:1[5-9][0-9]{2}|20[01][0-9]|2020)

1st Alternative1[5-9][0-9]{2}

1the literal 1 (49₁₀ / 61₈ / 31₁₆)

Character Class[5-9]

5-9one character from 5 (53₁₀) to 9 (57₁₀)

Character Class[0-9]{2}

{2}matches exactly 2 characters from the set below:

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

2nd Alternative20[01][0-9]

20the literal text 20

Character Class[01]

0the literal 0 (48₁₀ / 60₈ / 30₁₆)

1the literal 1 (49₁₀ / 61₈ / 31₁₆)

Character Class[0-9]

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

3rd Alternative2020

2020the literal text 2020

Character Class[0-9]{2,4}

{2,4}matches between 2 and 4 characters from the set below:

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

Character Class[0-9]

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

$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

^([a-z])(?!\1)([a-z])(?!\1|\2)[a-z](?:1[5-9][0-9]{2}|20[01][0-9]|2020)[0-9]{2,4}[0-9]$

New

abc1500999
abc15009999
abc150099999
abc202099999

bbc202099999
baa202099999