Currency Regular Expression

Question

I think I created a working regular expression for what I need. Just wondering if anyone can break it or see a shorter way to write it.

The regular expression shoul

Answer 1

Here is one shorter alternative (56 chars to your 114), which will work in almost all regex flavors:

^\$?(?=\(.*\)|[^()]*$)\(?\d{1,3}(,?\d{3})?(\.\d\d?)?\)?$

Example: http://www.rubular.com/r/qtYHEVzVK7

Explanation:

^                # start of string anchor
\$?              # optional '$'
(?=              # only match if inner regex can match (lookahead)
   \(.*\)          # both '(' and ')' are present
   |               # OR
   [^()]*$         # niether '(' or ')' are present
)                # end of lookaheand
\(?              # optional '('
\d{1,3}          # match 1 to 3 digits
(,?\d{3})?       # optionally match another 3 digits, preceeded by an optional ','
(\.\d\d?)?       # optionally match '.' followed by 1 or 2 digits
\)?              # optional ')'
$                # end of string anchor