How to add numbers from a sequence that contains numbers and letters in java?

Question

lets say the user submits this sequence: dadeer50dfder625dsf3 , the program should print the result of the sum of the numbers : 50+625+3. How can i do this ?

This is what i have done so far, but its not working. Can someone help me please :( :

String secuencia = JOptionPane.showInputDialog("Ingresa tu secuencia");
           int par = secuencia.length();
                     int sumatoria = 0;
         int sumatoria1 = 0;
                          for (int i = 0; i < par; i++) {
            String p = secuencia.substring(i, i +1); 
                        if(p.equals("1") || p.equals("2") || p.equals("3") || p.equals("4") || p.equals("5") || p.equals("6") || p.equals("7") || p.equals("8") || p.equals("9") || p.equals("0")){
                                for (int j = i + 1; j < par; j++) {
                                String n = secuencia.substring(j, j + 1);
                                 if(n.equals("1") || n.equals("2") || n.equals("3") || n.equals("4") || n.equals("5") || n.equals("6") || n.equals("7") || n.equals("8") || n.equals("9") || n.equals("0")){

                                     int v = Integer.parseInt(p);
                                     int y = Integer.parseInt(n);
                          sumatoria += v;       
                                     sumatoria1 += y ;

                        }      }}           

                        System.out.print(sumatoria);
                        System.out.println(sumatoria1);

Answer 1

You could String.split(String) , which takes a regular expression. I think you want non-digits, so you could use \\\\D+ . Something like,

String str = "dadeer50dfder625dsf3";
String[] arr = str.split("\\D+");
int total = 0;
StringBuilder sb = new StringBuilder();
for (String val : arr) {
    if (val.isEmpty()) {
        continue;
    }
    sb.append(val).append(" + ");
    total += Integer.parseInt(val);
}
sb.replace(sb.length() - 2, sb.length(), "= ");
System.out.print(sb);
System.out.println(total);

And the output is

50 + 625 + 3 = 678

Answer 2

Roberto,

It looks like you are on the right path, however the problem with your code is that it assumes the number is only a single character long. I think it adds 5+0+6+2+5+3 instead of the desired add.

I would suggest using the function String.split() to seperate out the pieces which contain numbers and the pieces that do not. I believe you can pass something like [A-Za-z] and that will return strings that only contain numbers in them(Assuming only letters and not other characters are used). http://docs.oracle.com/javase/7/docs/api/java/lang/String.html#split(java.lang.String)

Answer 3

Here's a simple code without using RegEx's like you told us in the commentaries :

public static void main(String[] args) {
    String str = "55blhalhalh3265hezubf565";
    boolean isLetter = false;
    String temp = "";
    int sum = 0;

    for (int i = 0 ; i < str.length() ; i++){
        switch(str.charAt(i)){
        case '0': 
        case '1': 
        case '2': 
        case '3': 
        case '4': 
        case '5': 
        case '6': 
        case '7': 
        case '8': 
        case '9':
            isLetter = false;
            temp += str.charAt(i);
            break;
        default :
            if (!isLetter)sum += Integer.parseInt(temp);
            isLetter = true;
            temp = "";
            break;
        }
    }
    if (!isLetter) sum += Integer.parseInt(temp);

    System.out.println("The final sum is " + sum);
}

I made the switch long on purpose to be very clear.

A little explanation :

The for iterates over all the chars of your String object of course. Then, the switch checks if it is a number or not :

• if it is the case, the boolean isLetter takes the false value and we concatenate the char to the previous number if there was

• if it is a letter, we add the already found number to the total sum.

Answer 4

Here are two versions.
The first shows how easy it is when using regular expression.
The second uses the constraints given in a comment. Since it said "substring", I'll assume that using Integer.parseInt() is ok.

// Using regular expression
String text = "dadeer50dfder625dsf3";
int sum = 0;
for (Matcher m = Pattern.compile("\\d+").matcher(text); m.find(); )
    sum += Integer.parseInt(m.group());
System.out.println(sum);

// Using only substring, for loops and length
String text = "dadeer50dfder625dsf3";
int sum = 0, numStart = -1;
for (int i = 0; i < text.length(); i++) {
    char c = text.charAt(i);
    if (c >= '0' && c <= '9') {
        if (numStart == -1)
            numStart = i;
    } else {
        if (numStart != -1)
            sum += Integer.parseInt(text.substring(numStart, i));
        numStart = -1;
    }
}
if (numStart != -1)
    sum += Integer.parseInt(text.substring(numStart));
System.out.println(sum);

Output from both

678

Answer 5

String str = "dadeer50dfder625dsf3";
    List<String> list = Arrays.asList(str.split("\\D+"));
    int sum = 0;
    for (String each : list) {
        try {
            sum += Integer.parseInt(each);
        } catch (Exception e) {
            // TODO: handle exception
        }
    }
    System.out.println(sum);