Develop Reference

Extra charcters in .csv output

After importing a CSV file and sorting it in to a 2-Dimensional array I get a couple of weird characters in only the first and possibly the last cell.
Expected output: S1358_R1
Actual output: S1358_R1
Does anyone know why these extra characters show up? The code used to do this is included below:
import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
public class open2 {
public static void main(String[] args) {
String line = "";
String splitBy = ",";
try {
//parsing a CSV file into BufferedReader class constructor
int i = 0;
String[][] ss = new String[10000][10000];
BufferedReader br = new BufferedReader(new FileReader("C:\\Users\\micha\\Documents\\spreadsheet.csv"));
while ((line = br.readLine()) != null) //returns a Boolean value
{
String[] cells = line.split(splitBy);
for (int j = 0; j < cells.length; j++) {
ss[i][j] = cells[j];
} // use comma as separator
i = i + 1;
}
System.out.println(ss[0][0]);
} catch (IOException e) {
e.printStackTrace();
}
}
}

How do I store the CSV file data into an array in Java?

Here is the CSV file I am using:
B00123,55
B00783,35
B00898,67
I need to read and store the first value entered in the file e.g. B00123 and store it into an array. A user can add to the file so it is not a fixed number of records.
So far, I have tried this code:
public class ArrayReader
{
static String xStrPath;
static double[][] myArray;
static void setUpMyCSVArray()
{
myArray = new double [4][5];
Scanner scanIn = null;
int Rowc = 0;
int Row = 0;
int Colc = 0;
int Col = 0;
String InputLine = "";
double xnum = 0;
String xfileLocation;
xfileLocation = "src\\marks.txt";
System.out.println("\n****** Setup Array ******");
try
{
//setup a scanner
/*file reader uses xfileLocation data, BufferedRader uses
file reader data and Scanner uses BufferedReader data*/
scanIn = new Scanner(new BufferedReader(new FileReader(xfileLocation)));
while (scanIn.hasNext())
{
//read line form file
InputLine = scanIn.nextLine();
//split the Inputline into an array at the comas
String[] InArray = InputLine.split(",");
//copy the content of the inArray to the myArray
for (int x = 0; x < myArray.length; x++)
{
myArray[Rowc][x] = Double.parseDouble(InArray[x]);
}
//Increment the row in the Array
Rowc++;
}
}
catch(Exception e)
{
}
printMyArray();
}
static void printMyArray()
{
//print the array
for (int Rowc = 0; Rowc < 1; Rowc++)
{
for (int Colc = 0; Colc < 5; Colc++)
{
System.out.println(myArray[Rowc][Colc] + " ");
}
System.out.println();
}
return;
}
public static void main(String[] args)
{
setUpMyCSVArray();
}
}
This loops round the file but doesn't not populate the array with any data. The outcome is:
****** Setup Array ******
[[D#42a57993
0.0
0.0
0.0
0.0
0.0

There is actually a NumberFormatException happening when in the first row when trying to convert the ID to Double. So I revised the program and it works for me.
import java.io.BufferedReader;
import java.io.FileReader;
import java.util.HashMap;
import java.util.Map;
import java.util.Scanner;
public class ArrayReader
{
static String xStrPath;
static Map<String,Double> myArray = new HashMap<>();
static void setUpMyCSVArray()
{
Scanner scanIn = null;
int Rowc = 0;
int Row = 0;
int Colc = 0;
int Col = 0;
String InputLine = "";
double xnum = 0;
String xfileLocation;
xfileLocation = "/Users/admin/Downloads/mark.txt";
System.out.println("\n****** Setup Array ******");
try
{
//setup a scanner
/*file reader uses xfileLocation data, BufferedRader uses
file reader data and Scanner uses BufferedReader data*/
scanIn = new Scanner(new BufferedReader(new FileReader(xfileLocation)));
while (scanIn.hasNext())
{
//read line form file
InputLine = scanIn.nextLine();
//split the Inputline into an array at the comas
String[] inArray = InputLine.split(",");
//copy the content of the inArray to the myArray
myArray.put(inArray[0], Double.valueOf(inArray[1]));
//Increment the row in the Array
Rowc++;
}
}
catch(Exception e)
{
System.out.println(e);
}
printMyArray();
}
static void printMyArray()
{
//print the array
for (String key : myArray.keySet()) {
System.out.println(key + " = " + myArray.get(key));
}
return;
}
public static void main(String[] args)
{
setUpMyCSVArray();
}
}
Output:

the code can't reader anything ,you file path incorrect.give it absoulte file path.
scanIn = new Scanner(new BufferedReader(new FileReader(xfileLocation)));

I use opencsv library to read from csv.
import com.opencsv.CSVReader;
public class CSV {
private static String file = <filepath>;
private static List<String> list = new ArrayList<>();
public static void main(String[] args) throws Exception {
try {
CSVReader reader = new CSVReader(new FileReader(file));
String[] line;
while ((line = reader.readNext()) != null) {
list.add(line[0]);
}
Object[] myArray = list.toArray();
System.out.println(myArray.length);
System.out.println(myArray[0]);
} catch (Exception e) {
e.printStackTrace();
}
}
}
Output printed as below
3
B00123

Failure to load .CSV file into 2d array

I'm trying to load a CSV file into a 2d array, but when I go to call it in main I receive the error
Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 0
In my code while the file has a next line, it splits up the line, stores it in a string array which will in turn be moved to the 2D array. I don't understand how there can be an error. Anyone willing to explain or am I just very dense?
public int rows = 0;
public int cols = 0;
public String[][] filetable = new String[rows][cols];
public void set_Array(File example)
{
try
{
FileReader file = new FileReader(example);
Scanner sc = new Scanner(file);
if(sc.hasNextLine())
{
String[] tokens = sc.nextLine().split(",");
cols = tokens.length;
rows++;
}
while(sc.hasNextLine())
{
rows++;
sc.nextLine();
}
}
catch (FileNotFoundException e)
{
System.out.println(e);
}
}
public void to_Array(File example)
{
try
{
FileReader file = new FileReader(example);
Scanner sc = new Scanner(file);
int r = 0;
while(sc.hasNextLine())
{
String[] tokens = sc.nextLine().split(",");
for(int c = 0; c < cols; c++)
{filetable[r][c] = tokens[c];}
r++;
}
}
catch (FileNotFoundException e)
{
System.out.println(e);
}
}

I don't know in which order you are calling set_Array and to_Array methods. But I guess, the problem is that you are essentially creating a 2D array of 0 rows and 0 sizes as public String[][] filetable = new String[rows][cols]; is called when rows=0 and cols=0. To rectify, call your set_Array method to assign proper values to rows and cols and then instantiate your 2D array inside your to_Array method.
public void to_Array(File example)
{// Now rows and cols will have proper values assigned
String[][] filetable = new String[rows][cols];
try
{
FileReader file = new FileReader(example);
Scanner sc = new Scanner(file);
int r = 0;
while(sc.hasNextLine())
{
String[] tokens = sc.nextLine().split(",");
for(int c = 0; c < cols; c++)
{filetable[r][c] = tokens[c];}
r++;
}
}
catch (FileNotFoundException e)
{
System.out.println(e);
}
}

Txt file into a double 2d array

I am trying to read a txt file into a array of doubles. I am using the following code which reads every line of the file:
String fileName="myFile.txt";
try{
//Create object of FileReader
FileReader inputFile = new FileReader(fileName);
//Instantiate the BufferedReader Class
BufferedReader bufferReader = new BufferedReader(inputFile);
//Variable to hold the one line data
String line;
// Read file line by line and print on the console
while ((line = bufferReader.readLine()) != null) {
System.out.println(line);
}
//Close the buffer reader
bufferReader.close();
}catch(Exception e){
System.out.println("Error while reading file line by line:"
+ e.getMessage());
}
However I want to store the txt file into a 2d double array.
I ve tried the above to load also the dimension of the txt. But I am having problems with the exceptions catch (NoSuchElementException e), it seems that it couldnt read the file.
try {
while (input.hasNext()) {
count++;
if (count == 1) {
row = input.nextInt();
r = row;
System.out.println(row);
continue;
} else if (count == 2) {
col = input.nextInt();
System.out.println(col);
c = col;
continue;
} else {
output_matrix = new double[row][col];
for (int i = 0; i < row; i++) {
for (int j = 0; j < col; j++) {
String el = input.next();
Double temp = Double.valueOf(el);
double number = temp.doubleValue();
//output_matrix[i][j] = el;
output_matrix[i][j] = number;
//System.out.print(output_matrix[i][j]+" ");
}
//System.out.println();
}
}
}
} catch (NoSuchElementException e) {
System.err.println("Sfalma kata ti tropopoisisi toy arxeioy");
System.err.println(e.getMessage()); //emfanisi tou minimatos sfalmatos
input.close();
System.exit(0);
} catch (IllegalStateException e) {
System.err.println("Sfalma kata ti anagnosi toy arxeioy");
System.exit(0);
}

You might want to be using the Scanner class for it, especially the Scanner.nextDouble() method.
Also, if you don't know in advance the dimensions of the array - I'd suggest using an ArrayList instead of a regular array.
Code example:
ArrayList<ArrayList<Double>> list = new ArrayList<>();
while ((line = bufferReader.readLine()) != null) {
ArrayList<Double> curr = new ArrayList<>();
Scanner sc = new Scanner(line);
while (sc.hasNextDouble()) {
curr.add(sc.nextDouble());
}
list.add(curr);
}

At firs declare a list and collect into it all read lines:
List<String> tempHistory = new ArrayList<>();
while ((line = bufferReader.readLine()) != null) {
tempHistory.add(line);
}
Then, after bufferReader.close(); convert this tempHistory list into double[][] array.
double[][] array = new double[tempHistory.size()][];
for (int i = 0; i < tempHistory.size(); i++) {
final String currentString = tempHistory.get(i);
final String[] split = currentString.split(" ");
array[i] = new double[split.length];
for (int j = 0; j < split.length; j++) {
array[i][j] = Double.parseDouble(split[j]);
}
}
It works, but as I added in comments, this is a not so good solution, and is better to use Collections instead of array.
BTW, it works even the rows lengths are different for different lines.

Read from a file in Java

Does anybody know how to properly read from a file an input that looks like this:
0.12,4.56 2,5 0,0.234
I want to read into 2 arrays in Java like this:
a[0]=0.12
a[1]=2
a[2]=0;
b[0]=4.56
b[1]=5
b[2]=0.234
I tried using scanner and it works for input like 0 4 5 3.45 6.7898 etc but I want it for the input at the top with the commas.
This is the code I tried:
import java.io.File;
import java.io.FileNotFoundException;
import java.util.Scanner;
public class IFFTI {
public static int size=0;
public static double[] IFFTInputREAL= new double[100];
public static double[] IFFTInputIMAG= new double[100];
static int real=0;
static int k=0;
public static void printarrays(){
for(int k=0;k<size;k++){
System.out.print(IFFTInputREAL[k]);
System.out.print(",");
System.out.print(IFFTInputIMAG[k]);
System.out.print("\n");
}
}
public static void readIFFT(String fileName){
try {
Scanner IFFTI = new Scanner(new File(fileName));
while (IFFTI.hasNextDouble()) {
if(real%2==0){
IFFTInputREAL[k] = IFFTI.nextDouble();
real++;
}
else{
IFFTInputIMAG[k] = IFFTI.nextDouble();
real++;
k++;}
}
try{
size=k;
}catch(NegativeArraySizeException e){}
} catch (FileNotFoundException e) {
System.out.println("Unable to read file");
}
}
}

I think this will do what you want:
String source = "0.12,4.56 2,5 0,0.234";
List<Double> a = new ArrayList<Double>();
List<Double> b = new ArrayList<Double>();
Scanner parser = new Scanner( source ).useDelimiter( Pattern.compile("[ ,]") );
while ( parser.hasNext() ) {
List use = a.size() <= b.size() ? a : b;
use.add( parser.nextDouble() );
}
System.out.println("A: "+ a);
System.out.println("B: "+ b);
That outputs this for me:
A: [0.12, 2.0, 0.0]
B: [4.56, 5.0, 0.234]
You'll obviously want to use a File as a source. You can use a.toArray() if you want to get it into a double[].

You will have to read the complete line.
String line = "0.12,4.56 2,5 0,0.234"; //line variable will recieve the line read
Then.. you split the line on the commas or the spaces
String[] values = line.split(" |,");
This will result in an array like this: [0.12, 4.56, 2, 5, 0, 0.234]
Now, just reorganize the contents between the two order arrays.

Reading from a file in Java is easy:
http://www.exampledepot.com/taxonomy/term/164
Figuring out what to do with the values once you have them in memory is something that you need to figure out.
You can read it one line at a time and turn it into separate values using the java.lang.String split() function. Just give it ",|\\s+" as the delimiter and off you go:
public class SplitTest {
public static void main(String[] args) {
String raw = "0.12,4.56 2,5 0,0.234";
String [] tokens = raw.split(",|\\s+");
for (String token : tokens) {
System.out.println(token);
}
}
}

EDIT Oops, this is not what you want. I don't see the logic in the way of constructing the arrays you want.
Read the content from the file
Split the string on spaces. Create for each element of the splitted array an array.
String input = "0.12,4.56 2,5 0,0.234";
String parts[] = input.split(" ");
double[][] data = new double[parts.length][];
Split each string on commas.
Parse to a double.
for (int i = 0; i < parts.length; ++i)
{
String part = parts[i];
String doubles[] = part.split(",");
data[i] = new double[doubles.length];
for (int j = 0; j < doubles.length; ++j)
{
data[i][j] = Double.parseDouble(doubles[j]);
}
}

File file = new File("numbers.txt");
BufferedReader reader = null;
double[] a = new double[3];
double[] b = new double[3];
try {
reader = new BufferedReader(new FileReader(file));
String text = null;
if ((text = reader.readLine()) != null) {
String [] nos = text.split("[ ,]");
for(int i=0;i<nos.length/2;i++){
a[i]=Double.valueOf(nos[2*i]).doubleValue();
b[i]=Double.valueOf(nos[2*i+1]).doubleValue();
}
}
for(int i=0;i<3;i++){
System.out.println(a[i]);
System.out.println(b[i]);
}
} catch (FileNotFoundException e) {
} catch (IOException e) {
} finally {
try {
if (reader != null) {
reader.close();
}
} catch (IOException e) {
}
}