Develop Reference

The problem with the word display if I have too many blank lines

I did not want to repeat the other question, I solved a problem in which I post the most common word in the text, but I have a problem, it does not work if I have more blank lines, how can I solve it?
I tried other ways of stackoverflow, but failed.
This is my code.
import java.io.*;
import java.util.*;
public class Main {
public static void main(String[] args) {
Map < String, Integer > map = new LinkedHashMap < String, Integer > ();
BufferedReader reader = null;
try {
reader = new BufferedReader(new InputStreamReader(System.in));
String currentLine = reader.readLine();
while (currentLine != null) {
String[] input = currentLine.replaceAll("[^a-zA-Z-\"\\n\\n\", \"\\n\"]", " ").toLowerCase().split(" ");
for (int i = 0; i < input.length; i++) {
if (map.containsKey(input[i])) {
int count = map.get(input[i]);
map.put(input[i], count + 1);
} else {
map.put(input[i], 1);
}
}
currentLine = reader.readLine();
}
String mostRepeatedWord = null;
int count = 0;
for (Map.Entry < String, Integer > m: map.entrySet()) {
if (m.getValue() > count) {
mostRepeatedWord = m.getKey();
count = m.getValue();
} else if (m.getValue() == count) {
String key = m.getKey();
if (key.compareTo(mostRepeatedWord) < 0) {
mostRepeatedWord = key;
}
}
}
System.out.println(mostRepeatedWord);
} catch (IOException e) {
e.printStackTrace();
} finally {
try {
reader.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}

Modify your for loop so that you're not adding to your map on a blank line.
for (int i = 0; i < input.length; i++) {
// Skip the blank lines
if (!input[i].trim().equals("")) {
if (map.containsKey(input[i])) {
int count = map.get(input[i]);
map.put(input[i], count + 1);
} else {
map.put(input[i], 1);
}
}
}

Java - Writing a Method to Count Lines In a Text File Without Throwing Exceptions

Below is a solution from Number of lines in a file in Java
to quickly count the number of lines in a text file.
However, I am trying to write a method that will perform the same task without throwing an 'IOException'.
Under the original solution is my attempt to do this with a nested try-catch block <-- (Is this usually done/frowned upon/ or easily avoidable??) which returns 0 no matter how many lines are in the given file (obviously a fail).
Just to be clear, I am not looking for advice on how to better use the original method that does contain the exception and, therefore, the context within which I am using it is irrelevant to this question.
Can somebody please help me write a method that counts the number of lines in a text file and does not throw any exceptions? (In other words, deals with potential errors with a try-catch.)
Original line counter by martinus:
public static int countLines(String filename) throws IOException {
InputStream is = new BufferedInputStream(new FileInputStream(filename));
try {
byte[] c = new byte[1024];
int count = 0;
int readChars = 0;
boolean empty = true;
while ((readChars = is.read(c)) != -1) {
empty = false;
for (int i = 0; i < readChars; ++i) {
if (c[i] == '\n') {
++count;
}
}
}
return (count == 0 && !empty) ? 1 : count;
} finally {
is.close();
}
}
My Attempt:
public int countLines(String fileName ) {
InputStream input = null;
try{
try{
input = new BufferedInputStream(new FileInputStream(fileName));
byte[] count = new byte[1024];
int lines = 0;
int forChar;
boolean empty = true;
while((forChar = input.read(count)) != -1){
empty = false;
for(int x = 0; x < forChar; x++){
if(count[x] == '\n'){
lines++;
}
}
}
return (!empty && lines == 0) ? 1 : lines + 1;
}
finally{
if(input != null)
input.close();
}
}
catch(IOException f){
int lines = 0;
return lines;
}
}

It is more robust to use char instead of byte for '\n' and return -1 in case of any errors, for example if the filename does not exist:
public static int countLines(String filename) {
BufferedReader br = null;
try {
br = new BufferedReader(new InputStreamReader(new FileInputStream(filename)));
char[] c = new char[1024];
int count = 0;
int readChars = 0;
boolean emptyLine = true;
while ((readChars = br.read(c)) != -1) {
for (int i = 0; i < readChars; ++i) {
emptyLine = false;
if (c[i] == '\n') {
++count;
emptyLine = true;
}
}
}
return count + (!emptyLine ? 1 : 0);
} catch (IOException ex) {
return -1;
} finally {
if (br != null)
try {
br.close();
} catch (IOException e) {
// Ignore intentionally
}
}
}

Sharing my attempt.
public static int countLines(String filename) {
InputStream is = new BufferedInputStream(new FileInputStream(filename));
int numLines = 0;
try {
byte[] c = new byte[1024];
int count = 0;
int readChars = 0;
boolean empty = true;
while ((readChars = is.read(c)) != -1) {
empty = false;
for (int i = 0; i < readChars; ++i) {
if (c[i] == '\n') {
++count;
}
}
}
numLines = (count == 0 && !empty) ? 1 : count;
} catch (IOException ex) {
numLines = 0;
} catch (FileNotFoundException ex) {
System.out.println("File not found.");
numLines = 0;
} finally {
is.close();
}
return numLines;
}

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.

Loading a CSV into multidimensional array

So what i need to do is load a csv file to a JTable with dynamic array(anywhere between 2 and 6 values), first i came up with this solution:
private String[][] Load()
{
try {
final BufferedReader br = new BufferedReader(new FileReader("FilePath");
try{
String line;
final ArrayList<String> List1 = new ArrayList<String>();
final ArrayList<String> List2 = new ArrayList<String>();
final ArrayList<String> List3 = new ArrayList<String>();
while((line = br.readLine()) != null)
{
final String[] parse = line.split(",");
List1.add(parse[0]);
List2.add(parse[1]);
List3.add(parse[2]);
}
final ArrayList[] lists = new ArrayList[]{List1, List2, List3};
final String[][] temp = new String[List1.size()][List1.get(0).split(",").length];
for(int x = 0 ; x < temp.length ; x++)
{
for(int y = 0 ; y < temp[x].length ; y++)
{
temp[x][y] = (String) lists[y].get(x);
}
}
return temp;
}finally
{
br.close();
}
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
which i thought was horrible, so i came up with this solution:
private String[][] Load()
{
try
{
final BufferedReader br = new BufferedReader(new FileReader("FilePath"));
try
{
final List<String> raw = new ArrayList<String>();
String line;
while((line = br.readLine()) != null)
raw.add(line);
final String[][] temp = new String[raw.size()][raw.get(0).split(",").length];
for(int x = 0 ; x < raw.size() ; x++)
{
final String[] parse = raw.get(x).split(",");
for(int y = 0 ; y < temp[x].length ; y++)
{
temp[x][y] = parse[y];
}
}
return temp;
}finally
{
br.close();
}
}catch(IOException e){
e.printStackTrace();
}
return null;
}
but i'm not so sure about that either, both of them work just fine so really all i'm asking is, how would you do it?
Edit: can't really use external libs with this project.

Converting CSV File to Java - Copied in Backwards

I previously asked a question about converting a CSV file to 2D array in java. I completely rewrote my code and it is almost reworking. The only problem I am having now is that it is printing backwards. In other words, the columns are printing where the rows should be and vice versa. Here is my code:
int [][] board = new int [25][25];
String line = null;
BufferedReader stream = null;
ArrayList <String> csvData = new ArrayList <String>();
stream = new BufferedReader(new FileReader(fileName));
while ((line = stream.readLine()) != null) {
String[] splitted = line.split(",");
ArrayList<String> dataLine = new ArrayList<String>(splitted.length);
for (String data : splitted)
dataLine.add(data);
csvData.addAll(dataLine);
}
int [] number = new int [csvData.size()];
for(int z = 0; z < csvData.size(); z++)
{
number[z] = Integer.parseInt(csvData.get(z));
}
for(int q = 0; q < number.length; q++)
{
System.out.println(number[q]);
}
for(int i = 0; i< number.length; i++)
{
System.out.println(number[i]);
}
for(int i=0; i<25;i++)
{
for(int j=0;j<25;j++)
{
board[i][j] = number[(j*25) + i];
}
}
Basically, the 2D array is supposed to have 25 rows and 25 columns. When reading the CSV file in, I saved it into a String ArrayList then I converted that into a single dimension int array. Any input would be appreciated. Thanks

so you want to read a CSV file in java , then you might wanna use OPEN CSV
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import au.com.bytecode.opencsv.CSVReader;
public class CsvFileReader {
public static void main(String[] args) {
try {
System.out.println("\n**** readLineByLineExample ****");
String csvFilename = "C:/Users/hussain.a/Desktop/sample.csv";
CSVReader csvReader = new CSVReader(new FileReader(csvFilename));
String[] col = null;
while ((col = csvReader.readNext()) != null)
{
System.out.println(col[0] );
//System.out.println(col[0]);
}
csvReader.close();
}
catch(ArrayIndexOutOfBoundsException ae)
{
System.out.println(ae+" : error here");
}catch (FileNotFoundException e)
{
System.out.println("asd");
e.printStackTrace();
} catch (IOException e) {
System.out.println("");
e.printStackTrace();
}
}
}
and you can get the related jar file from here