How do I input data from a CSV file into my code?

Question

I have a CSV file that is like:

Orbit,a,e,i
LEO,7168000,0,90
MEO,20200000,0,54

What I want is that using scanner, I will be able to choose one of the two orbits I have in the CSV file. Let's say for example, using scanner if I put 1 in the console, it chooses the row of the CSV file: LEO,7168000,0,90 and if I put 2 the line: MEO,20200000,0,54.

After that from the row chosen it saves each parameter in a variable skipping the name (LEO,MEO). For example if I choose LEO orbit, it saves the variables like:

double a = 7168000;
double e = 0;
double i = 90;

So in the end I can use those parameters in my program. Thank you for your answers.

And how would it be coded? I am sorry but I am quite new using Java. — Raúl
– Raúl, Commented Mar 13, 2019 at 14:43

tuanngocptn · Accepted Answer · 2019-03-13 03:12:57Z

1

Csv file is a plain text file and separates with , character for each cell and \n for each row.

The easy way, you only need using FileInputStream to read and split \n and , character for using.

File file = new File("file.csv");
FileInputStream fis = null;
String dataStr = "";
try {
    fis = new FileInputStream(file);
    int content;
    while ((content = fis.read()) != -1) {
        dataStr += (char) content;
    }
} catch (IOException e) {
    e.printStackTrace();
}
// convert to array rows string
String[] dataRows = dataStr.split("\n");

// loop rows to get cells string
for (int i = 0; i < dataRows.length; i++) {
    String[] dataCells = rowData[i].split(",");
    //do what ever you want with dataCells
}

Thanks for read.

answered Mar 13, 2019 at 3:12

tuanngocptn

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6 Comments

Crutch Master Over a year ago

Not so fast. Sepatator may be "," tab ";" or something else. Strings may be contains sepatators and must be escaped, etc.

Raúl Over a year ago

Thank you for your answer. But how can I do the scanner part to for example from the dataCells choose only one of the options because if I print dataCells[1] I get: a 7168000 20200000 And I only want to get one of the values.

Raúl Over a year ago

And also the dataCells are String and I want each value as double as I will use it later on the code as parameter.

tuanngocptn Over a year ago

@Raúl you can use Double Array to save data for easy get data like a matrix of string String[][], And if you need to use data with double type, you can use method Double.parseDouble(string).

tuanngocptn Over a year ago

data with double type, you can use method Double.parseDouble(string). another way, you create the class that defines all attribute you need Orbit,a,e,i. Then define the list of the class defined and set it for each value of dataCells after split.

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