Question

I am trying match a formula using regular expressions.

1. The formula should strictly contain these three letters only(L,W,H).
2. Should allow only product operation i.e (L*W*H, L*W, L*H etc).
3. Also instead of adding squared values, It should allow something
   like this(L*L*L*W*W*H*H)
4. Also it should not allow the asterisk symbol at the end.

I tried myself and came up with this

^([L|W|H]\*{0,1})?(([L|W|H]\*{0,1}){0,9})?([L|W|H]{0,1})$

But this allows adding letters continuously something like "LLL*WW*HHH**". Please help me out guys.

Answer 1

It seems like you want this:

^[LWH](\*[LWH])*$

Explanation:

• ^ the start of string
• [LWH] one of L,W,H
• (\*[LWH])* (a literal * followed by one of L,W,H) any number of times
• $ the end of string