Regex For digit count in an alphanumeric string

Question

How can i validate following logic from regex

• Allow Dollar($),Comma(,),Decimal(.) and digit(0-9)
• Can have only 8 digit before Decimal irrespective of $ and comma
• 2 digit after decimal

Allowed string Example:

• 99999999.99
• $99999999.99
• $9,999,9999.99
• $9999,99,99.99

Does not allow : - $999999999.99 ( 9 digit before decimal) - $99,99,999,99.99

Mean i want to restrict the count of digit only before decimal. How can i achieve this. Thanks in Advance

Answer 1

/^(\$?(\,?\d){1,8}\.\d{2}$)/gm

Regex Demo

Answer 2

You can use this regex:

/^\$?(?:,?\d){1,8}(?:\.\d{1,2})?$/gm

RegEx Demo

Explanation:

^              # Line start
\$?            # match optional $ at start
(?:,?\d)       # Match an optional comma followed by a digit and use non-capturing group
{1,8}          # up to 8 occurrence of previous group
(?:\.\d{1,2})? # followed by optional decimal point and 1 or 2 digits
$              # line end