How do you convert string arraylist to double using for loop to calculate?

Question

I'm given the data.txt file and have to calculate the total amount using ArrayList

my data.txt file contains:

32.14,235.1,341.4,134.41,335.3,132.1,34.1

so far I have

public void processFile() throws IOException
{
    File file = new File("SalesData.txt");

    Scanner input = new Scanner(file);
    ArrayList<String> arr = new ArrayList<String>();
    String line = input.nextLine();

    StringTokenizer st = new StringTokenizer(line, ",");

    while (st.hasMoreTokens())
    {
        arr.add(st.nextToken());
    }

    setArrayListElement(arr); //calls setArrayListElement method

}

and here is my setArrayListElement method:

private void setArrayListElement(ArrayList inArray)
{                
    for (int i = 0 ; i < inArray.size() ; i++)
    {
         // need to convert each string into double and sum them up
    }
}

Can I get some help??

Answer 1

1. Never use doubles for monetary calculations (Previous answer is also wrong)
2. Never refer to a concrete class. The interface in this case is List arr = new ArrayList();

To your specific answer:

BigDecimal summed = BigDecimal.ZERO;

for (int i = 0 ; i < arr.size() ; i++) {
 final String value  = arr.get(i);
 try{
  BigDecimal bd = new BigDecimal(value);
  summed = summed.add(bd);
 } catch(NumberFormatException nfe){
       //TODO: Handle
 }
}

...

Answer 2

您必须使用Double.valueOf() ：

Double.valueOf(string);

Answer 3

Double value = Double.parseDouble(yourString);

Answer 4

I post you the method to calculate the total amount, dont forget to control exceptions.

    private Double setArrayListElement(ArrayList inArray) throws NumberFormatException
{   
    Double amount=0;    
    for (int i = 0 ; i < inArray.size() ; i++)
    {
       amount= amount+Double.valueOf(inArray.get(i));
    }
    return amount;
}