Parsing a currency String in java

Question

Suppose I'm supplied with a String which is like "$123,456,56.25" or "123'456.67" or something similar to this (with digits and a decimal point and some seperator like , or ' or something else which is not predictable). I need to write a method which takes an argument like the one above and returns a String like "12345656.25" or "123456.67" respectively.

Could you please suggest the most efficient and readable code to achieve this?

Note: I'm aware of going through each indexes and checking for whether its retunrs true for Character.isDigit(charAtInedx) or if(charAtInedx == '.') I'm looking for a more optimized solution both in terms of efficiency and readability

Thanks.

Clam

formatting is when you try to output a string. "decoding" a given string is usually called parsing. – Sexivalent

@Sexivalent Thanks a lot for the info. I never thought that way. – Clam

Do you need to consider formats like 123.456.67 or 123.456,67? – Mccollough

I'm trying to refactor a piece of code which reads ` StringBuffer buffer = new String Buffer (stringInput);for ( int i=0; i<buffer.length; i++){ if(buffer.charAt(i)) != '0' && buffer.charAt(i) != '1'` ..... etc && buffer.charAt(i) != '.'{ buffer.deleteCharAt(i); i= i-1;}. So I assume any code suggestion would be better than than current implementation. – Clam

Answer 1

String newStr = oldStr.replaceAll("[^\\d.]+", "")

This will drop any character that is not either a digit or a period

Altair

@jarnbjo Please re-read the question: with digits and a decimal point and some seperator – Altair

Even I'm not sure about the variety of inputs this method may receive. But looking at the current code I'm sure the regular expression you suggested would suffice. Thanks. – Clam

00000000042. will pass that RegEx and that doesn't look like a valid currency value to me. – Therese

@Therese you're absolutely right. This is not a universal currency fixer, but a regex for the specific situation the OP mentioned. – Altair

Sure. But reading op's title it's clear what the intent here is, and I don't think allowing a string of fifty decimal points is helpful. It may technically satisfy what op said but a better answer would have provided some/additional guidance IMO. – Therese

@Therese feel free to provide that answer – Altair

Answer 2

If you want to handle monetary values correctly, you will want to have a look at the NumberFormat class, specifically for your case NumberFormat.parse(String). The following article also discusses the problems (and solutions) to handling money in Java:

http://www.javapractices.com/topic/TopicAction.do?Id=13

Other related classes include: Currency and of course BigDecimal.

Mccollough

Answer 3

To parse a currency instance in Java, you can use the NumberFormat.getCurrencyInstance object. For example:

import java.text.NumberFormat;
import java.text.ParseException;

public class Main {
    public static void main(String[] args) throws ParseException {
        NumberFormat currency = NumberFormat.getCurrencyInstance(); // get the currency formatter
        String price = currency.format(19292.282); // format as a currency
        System.out.println(price); // $19,292.28

        Number parsePrice = currency.parse(price);
        System.out.println(parsePrice); // 19292.28
    }
}

Keep in mind that this is just a quick example, and you would need to account for exceptions as well.

Jataka