Replace non numeric characters from a string using regular expressions and make it a number

Sometimes you may want to exclude the non numeric characters from a string and retain only the digits to make it a valid number. A typical example is order id in a sales order. Many companies add some extra characters as a prefix to the order number to identify the customer or vendor. However, those prefix may not have any real purpose in the data and may need to be stripped off before we can use that order number to retrieve the order details from database.

Regular expressions provide an easy way to remove all non numeric characters from the string.

Code sample:

string orderString = "PON63320";
string orderNumber = Regex.Replace(orderString, @"[^\d]", "");
int orderId = int.Parse(orderNumber);