How to validate version number using regex pattern

Question

I have to validate version number pattern for following examples:

A1
aabc1
AabC134
aabc12.2
aA1.2.3
0.1.1
0.0.2
a.b.c
a.1.2
a.0.0
1.0.0
1.0
1

B

Answer 1

I might just use negative lookaheads to assert that the blacklisted version numbers do not appear, and otherwise proceed along the lines of what you are already doing:

 ^(?!^(?:0|0\.0\.0|000\.000\.000|0000\.00\.00)$)[A-Za-z0-9]+(?:\.[A-Za-z0-9]+){0,2}$

Demo