extractDigits method
Extracts all numerical digits from the string and returns them as a new string.
All non-digit characters (including letters, symbols, and spaces) are removed.
@returns A new string containing only the digits.
Example:
final messy = 'Price: $12.99 USD';
print(messy.extractDigits()); // "1299"
Implementation
String extractDigits() => replaceAll(RegExp(r'\D'), '');