Regular Expressions 101

^start of line

Negative Lookahead(?!.*([A-Z]{2,}|[0-9]{2,}))

.*any character (except for line terminators), repeated any number of times

Group 1([A-Z]{2,}|[0-9]{2,})

1st Alternative[A-Z]{2,}

Character Class[A-Z]{2,}

{2,}matches at least 2 characters from the set below:

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

2nd Alternative[0-9]{2,}

Character Class[0-9]{2,}

{2,}matches at least 2 characters from the set below:

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

Character Class[A-Z0-9]+

+matches at least one character from the set below:

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

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.

Search reference

Regular Expression

^(?!.*([A-Z]{2,}|[0-9]{2,}))[A-Z0-9]+$

New

A
1
A1
1A
A1A
1A1
A1B2C3D4
AA11
11AA
A1B2CCC
A1B2222