Read CSV and convert string to double

Question

I am new to Java and I am reading a csv file using open CSV and my code is below:

import java.io.FileReader; import java.util.Arrays; import au.com.bytecode.opencsv.CSVReader; public class ParseCSVLineByLine { double arr []=new arr[10]; public static void main(String[] args) throws Exception { //Build reader instance //Read data.csv //Default seperator is comma //Default quote character is double quote //Start reading from line number 2 (line numbers start from zero) CSVReader reader = new CSVReader(new FileReader("data.csv"), ',' , '"' , 1); //Read CSV line by line and use the string array as you want String[] nextLine; int i=0; while ((nextLine = reader.readNext()) != null) { if (nextLine != null && i<10) { //Verifying the read data here arr[i]=Double.parseDouble(Arrays.toString(nextLine).toString()); System.out.println(arr[i]); } i++; } } }

But this does not works.But when I only print

Arrays.toString(nextLine).toString()

This prints

[1] [2] [3] . . . . [10]

I think the conversion is having the problem.Any help is appreciated.

Arrays.toString(nextLine) will most likely result in something that isn't parseable as a double, since even with only one element you'll get the strings you posted, i.e. "[1]". Why not just Double.parseDouble(nextLine[index]) where index is probably 0? — Thomas
– Thomas, Commented Jan 10, 2017 at 13:44

GhostCat · Accepted Answer · 2017-01-10 13:45:29Z

Thing is:

"[1]"

is not a string that could be parsed as number!

Your problem is that you turn the array as a whole into one string.

So instead of calling

Arrays.toString(nextLine).toString()

iterate nextLine and give each array member to parseDouble()!

Besides: I am pretty sure you receive a NumberFormatException or something alike. The JVM already tells you that you are trying to convert an invalid string into a number. You have to learn to read those exception messages and understand what they mean!

Long story short: your code probably wants to parse "[1]", but you should have it parse "1" instead!

Collectives™ on Stack Overflow

Read CSV and convert string to double

1 Answer 1

Comments

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Related