RegEx to match Bitcoin addresses?

Question

I am trying to come up with a regular expression to match Bitcoin addresses according to these specs:

A Bitcoin address, or simply address, is an iden

Answer 1

[^OIl] matches any character that's not O, I or l. The problems in your regex are:

• You don't have a $ at the end, so it'd match any string beginning with a BC address.
• You didn't count the first character in your {27,34} - that should be {26,33}

However, as mentioned in a comment, a regex is not a good way to validate a bitcoin address.