Parse a string from a sensor containing 3 floats

Question

I'm trying to parse information from a temperature sensor. Sensors sends a String with the format:

Temp: 1   388  2   358  3   200?    
Temp: 1   388  2   200?  3   200?  

(First String contains a valid channel 2 sample and channel 3 disconnected, and second String has channel 2 and 3 disconnected).

I need to parse those "dat" which is a float without the dot, and I cant use String.split() because if the sensor doesn't detects anything it adds a '?' to the end of "dat". Output should be:

Temp[0]= 38.8
Temp[1]= 35.8
Temp[2]= 20.0

Also I need to parse that '?' to say if a channel it's disconnected.

Answer 1

I try to use split() to solve this problem, and did't see anything wrong you say.

public static void parseData(String data) {
    String[] args = data.split("\\s+");
    for (int i=2; i<7; i+=2) {
        if (args[i].charAt(args[i].length() - 1) == '?') {
            args[i] = args[i].substring(0, args[i].length() - 1);
        }
        double val = Double.parseDouble(args[i]) / 10;
        System.out.println("Temp[" + (i-1)/2 + "]= " + val);
    }
}

Answer 2

Probably the most easy approach would be to use String.split("\\\\s") this will provide an array of Strings. For example:

 Temp: 1   388  2   358  3   200?  => {"Temp:", "1", "388", "2", "358", "3", "200?"}

Knowing that the first temperature should be the 3rd column you can start processing from there. For obtaining numeric values you can use Integer.parse(...) . For floats you can divide by 10. You can check whether it has a trailing "?" with String.endsWith(...) . For more complicated processing you can use different regexs. More information here and here about regex in java.

How do you receive your input? Where do you read it from? A good and simple solution could be the scanner .

Answer 3

Here you go:

Scanner line = new Scanner(sensorStream);
while (line.hasNext()) {
    line.next(); // Temp:
    line.next(); // #

    int firstReading = line.nextInt(); // 388
    float realFirstReading = firstReading/10.0; // 38.8

    line.next(); // #
    int secondReading = line.nextInt(); // 358
    float realSecondReading = secondReading/10.0 // 35.8

    line.next(); // #
    int thirdReading = line.nextInt(); // 200
    float realThirdReading = thirdReading / 10.0; // 20.0
    // do what you will with it
}

If you need further help, do leave a comment...