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JAVA - Not able to properly fill multidimentional array from another array

I have a string of values separated by commas that I converted into an array, which I was then going to use to create a 2D array. When creating a loop to add the data from the first array to the 2D array it is repeating the data.
The output I'm getting is:
4428,40,401,610,2016,3821,31,347,572,2015,4381,38,341,520,2014,2536,17,193,290,2013,4295,39,371,552,2012,4643,45,343,502,2011,3922,28,312,475,2010,4434,30,350,541,2009,4038,28,341,536,2008,218,1,20,28,2007,46,0,6,15,2006,65,0,9,16,2005,4428,40,401,610,2016,3821,31,347,572,2015,4381,38,341,520,2014,2536,17,193,290,2013,4295,39,371,552,2012,4643,45,343,502,2011,3922,28,312,475,2010,4434,30,350,541,2009,4038,28,341,536,2008,218,1,20,28,2007,46,0,6,15,2006,65,0,9,16,2005,4428,40,401,610,2016,3821,31,347,572,2015,4381,38,341,520,2014,2536,17,193,290,2013,4295,39,371,552,2012,4643,45,343,502,2011,3922,28,312,475,2010,4434,30,350,541,2009,4038,28,341,536,2008,218,1,20,28,2007,46,0,6,15,2006,65,0,9,16,2005,4428,40,401,610,2016,3821,31,347,572,2015,4381,38,341,520,2014,2536,17,193,290,2013,4295,39,371,552,2012,4643,45,343,502,2011,3922,28,312,475,2010,4434,30,350,541,2009,4038,28,341,536,2008,218,1,20,28,2007,46,0,6,15,2006,65,0,9,16,2005,4428,40,401,610,2016,3821,31,347,572,2015,4381,38,341,520,2014,2536,17,193,290,2013,4295,39,371,552,2012,4643,45,343,502,2011,3922,28,312,475,2010,4434,30,350,541,2009,4038,28,341,536,2008,218,1,20,28,2007,46,0,6,15,2006,65,0,9,16,2005
and the correct output should be:
4428,40,401,610,2016,3821,31,347,572,2015,4381,38,341,520,2014,2536,17,193,290,2013,4295,39,371,552,2012,4643,45,343,502,2011,3922,28,312,475,2010,4434,30,350,541,2009,4038,28,341,536,2008,218,1,20,28,2007,46,0,6,15,2006,65,0,9,16,2005
Expected results:
{{4428,40,401,610,2016}
{3821,31,347,572,2015}
{4381,38,341,520,2014}
...} and so on, every 5
My code for adding the array to the 2D array is below:
{String[] columns = {"Yards","Touchdowns","Attempts","Incompletions","Year"};
String[] data1 = results1.split(",");
Object [][] data11 = new Object[columns.length][data1.length];
for(int i = 0; i<columns.length;i++){
for(int j = 0; j<data1.length;j++){
data11[i][j] = data1[j];
//System.out.print(data11[i][j]+",");
}
}}
EDIT: Solution!
Object [][] data11 = new Object[data1.length/columns.length][columns.length];
int column = -1;
for(int j = 0; j<data1.length;j++){
if(j % columns.length == 0) column = column+1;
data11[column][j % 5] = data1[j];
}

Maybe this work for you:
Object [][] data11 = new Object[columns.length][data1.length / 5];
int column = -1;
for(int j = 0; j<data1.length;j++){
if(j % 5 == 0) column = column + 1
data11[j % 5][column] = data1[j];
}
Note the matrix size changed and the assignation too. Haven't tried, probably you can make a prettier version. Hope it helps!

You also loop the first array (i), so he will repeat it. Just write this:
data11[0][j] = data1[j];
Or even don't do the first loop at all, depending on what you need.
Assuming your output, you only want to fill in the first position (0) of the array.

Java * Two-Dimensional Array * Plotting Points on Array [duplicate]

This question already has an answer here:
Java - Two-Dimensional Arrays - Plotting Points
(1 answer)
Closed 6 years ago.
I have an assignment for a JAVA class I am taking. We are discussing two-dimensional arrays, however on this particular assignment, I can not figure out how to return back specific points and set those points with a specific value. Here is the assignment:
Write a method called create2DArray that will fill, create, and return a 10 x 10 2d array with random numbers in the range of 1 to 100. Write a method called print2DArray that will print a 10 x 10 2D array in row column fashion. Write a method called createCoords that will search the 2D array looking for any value that is evenly divisible by 3. Once you have found a number you should log the row, column location. This means when your method finishes it should produce a list of coordinates that I can use to plot my graph. This method must also return the number of coordinates that are divisible by 3 so that I know how many points there are to plot. I am not particular as to how the coordinates are returned back as long as I get a list of the row, column locations. So, I will leave it to you to work out a mechanism for returning the values. To test that you have logged the coordinates create another function called fillLocations that will fill the locations in the array you have logged with -1. So, your program should flow in this order 1.create2DArray 2.print2DArray 3.createCoords 4.fillLocations 5.print2DArray
I understand and have completed create2DArray and print2DArray, but I can not figure out createCoords and fillLocations. Here is what I have so far, but it does not work and there are errors present:
public int createCoords(int row1, int col1){
int[][] coords = new int[row1][col1];
int[][] count = new int[0][0];
int co = 0;
for(int row = 0; row < 10; row++)
{
for(int col = 0; col < 10; col++)
{
if(coords[row][col] % 3 == 0)
co++;
return count[row][col];
}
}
return co;}
public int fillLocations(int[][] count){
int x = 0;
int y = 0;
for(int row = 0; row < 10; row++)
{
for(int col = 0; col < 10; col++)
{
if(count[row][col] % 3 == 0)
x = row;
y = col;
break;
}
}
return (x, y);}

I'm not going to write the code, but pretty much how I would go about doing this is:
I would have a separate 2d boolean array the same size as the 2d int array, auto filled with false. This would go in createCoords.
use nested for loop to cycle through all addresses of the 2d int array, and when i find a number that's divisible by three, i mark the corresponding point on the boolean array as 'true'. This would also go in createCoords.
after the for loops finish, I then look at the original 2d int array and boolean array. i would use the nested for loops again, and when i find a true value on the boolean array, i would mark the corresponding location on the int array as -1. This would go in fillLocations. You should also pass the 2d boolean array to fillLocation along with the 2d int array.
Good luck!
EDIT: this is assuming that the FillLocation function REPLACES values in the 10x10 int array with -1. That's what I interpreted your question to be. Please correct me if i'm wrong. I also added a short description at the end of each paragraph where each segment of code would go.

There are couple of problems with your code. Firstly, for the fillLocations method, you are expected to return the NUMBER of cells ([row][column]) where the value is divisible by 3. This means that for each value that passes the test:
if(coords[row][col] %3 === 0)
Then you should increment the counter by 1.
So for this part, your code would look like:
int [][] your2DArray = new int[10][10];
...
private int getNumberOfValuesDivisibleByThree(){
int numberOfValuesDivisibleByThree = 0;
for (int row=0; row < your2DArray.length; row++){
for(int col = 0; col < your2DArray[0].length; col++){
if(your2DArray[row][col] % 3 === 0){
//value at this coordinate or in this cell is divisible by 3
//here you can 'log' the coordinates as required -
System.out.println(row+","+col);
//increment the count
numberOfValuesDivisibleByThree +=1;
}
}
}
//return the final count
return numberOfValuesDivisibleByThree;
}
Please see how to create and manipulate a 2D array in Java. Syntax for creating a two-dimensional array

Storing contents of a webtable in a 2d matrix

I am trying to get the contents of a webtable using selenium and then store the contents in a 2d matrix.
Below is my code :
//Locate the webtable
WebElement reportTable = driver.findElement(By.xpath("//*[#id='pageContainer']/div/div[2]/table[2]"));
int rowCount = driver.findElements(By.xpath("//*[#id='pageContainer']/div/div[2]/table[2]/tbody/tr")).size(); //Get number of rows
System.out.println("Number of rows : " +rowCount);
String[][] reportMatrix = new String[rowCount-1][]; //Declare new 2d String array
//rowCount-1 because the first row is header which i don't need to store
int mainColCount = 0;
for(int i=2;i<=rowCount;i++) //Start count from second row, and loop till last row
{
int columnCount = driver.findElements(By.xpath("//*[#id='pageContainer']/div/div[2]/table[2]/tbody/tr["+i+"]/td")).size(); //Get number of columns
System.out.println("Number of columns : " +columnCount);
mainColCount = columnCount;
for(int j=1;j<=columnCount;j++) //Start count from first column and loop till last column
{
String text = driver.findElement(By.xpath("//*[#id='pageContainer']/div/div[2]/table[2]/tbody/tr["+i+"]/td["+j+"]/div")).getText(); //Get cell contents
System.out.println(i + " " + j + " " + text);
reportMatrix[i-2][j-1] = text; //Store cell contents in 2d array, adjust index values accordingly
}
}
//Print contents of 2d matrix
for(int i=0;i<rowCount-1;i++)
{
for(int j=0;j<mainColCount;j++)
{
System.out.print(reportMatrix[i][j] + " ");
}
System.out.println();
}
This gives me a Null Pointer Exception at "reportMatrix[i-2][j-1] = text".
I don't understand what I am doing wrong. Do I have to give even the second index when I declare the 2d array ?
Thanks in advance.

Unless you're a student who is studying multi-dimensional arrays, or you are otherwise constrained by an API you're required to use, just avoid arrays. You'll stay saner longer :)
If you HAVE to use a 2D array, it's wise to remember that you are not actually creating a matrix. You are creating a 1D array, and each element of this array is another 1D array. When you think of it that way, it becomes clear that you definitely have to initialize the "columns" arrays as well as the "rows" array.
This line:
String[][] reportMatrix = new String[rowCount-1][];
will initialize report matrix to have rowCount - 1 rows, and null for each and every set of columns.
Inside your first loop, after you have identified the number of columns, you want to do something like so:
reportMatrix[i] = new String[columnCount];
for(int j=1;j<=columnCount;j++) ...
This will allow you to have different number of columns in each row, if necessary.
Then, in your print loop, you should use the array lengths to print out the rows and columns. Remember to subtract 1 from the length attribute, since the this represents the number of elements in the array, and we almost always use zero-indexed for loops.
//Print contents of 2d matrix
for(int i=0; i < reportMatrix.length - 1; i++)
{
for(int j=0; j < reportMatrix[i].length - 1; j++)
{
System.out.print(reportMatrix[i][j] + " ");
}
System.out.println();
}

Converting String elements from an array to as values into an integer Array

I'm not allowed to use methods from any class except String and IO Class
So my code snippet is:
String line = reader.readLine();
while (line != null) {
String[] elements = line.split(",");
// Array could be too big if there are multiple occurances of
// the same number
// Array length + 1 because I can't use the 0 and with a input line of
// 1,2,3 for example would be the length 3 but I would have the
// numbers 0,1,2 in the Array as my index.
String[][] placeholderMatrix = new String[elements.length+1][elements.length+1];
for(int i = 0; i < elements.length-1; i++){
placeholderMatrix[(int)elements[i]][(int)elements[i+1]] = 1;
}
line = reader.readLine();
}
In the File I'm getting are only numbers like that: 1,2,3,4,5,8,7,4
So in my splitted String Array are only Numbers but now if I want to use them as my index for my Matrix(placeholderMatrix)
My problem is in my for loop where I want to use them as my Index I can't use them because it is a String Array. Normally I would use Integer.parseInt but I'm not allowed to :/
Any ideas on how I can implement them as my Index? and any Idea how I can get the perfect length of my Matrix? Because If I get the following numbers: 1,2,2,2,3 My Matrix should only have the numbers:
0 1 2 3
1
2
3
But if I'm using elements.length+1 for the length of my Matrix I would get the numbers 0 1 2 3 4 5
Hope you could understand my problem. Sorry for my bad english and Thanks in advance.
Edit: SO i got another problem with that. If I implement the method(parseInt) of Dici and am using it in the line "placeholderMatrix[parse(elements[i])][parse(elements[i+1])] = 1;" I'm getting the error ArrayOutOfBounce because my defined Array is just the length of my splitted String Array elements. But if I define it with Integer.MAX_VALUE as my length I get a memory error because it is too big. Any ideas?
Edit2: My Task:
I have to take a row of Numbers seperated by ",". (I will split it with the String split method to get only the numbers) Now I have to create a Matrix(2 dimensional Array) and look for the number at the index i of my new String Array and the number at the index i + 1 and have to take the first Number as my column and th second as my row (or vice versa) and implement at that point a 1. Now are my Numbers I will get from 1 to Integer.MAX_VALUE so I would have to create such a big Matrix but this isn't possible because I get the MemoryError.
Error: java.lang.OutOfMemoryError: Requested array size exceeds VM limit
at Test.main(Test.java:29)
To understand what I have to do: http://de.wikipedia.org/wiki/Adjazenzmatrix the image at the right but for numbers from to Integer.MAX_VALUE so my 2D Array has to be defined with the length of Integer.MAX_VALUE?
Edit:
So Dici asked for an example:
My Sequence could be: 1,2,5,4
So my Matrix should be:
Hope this is what you wanted Dici
But the numbers I can get from the sequence are 1 to Integer.MAX_VALUE

For converting strings to integers, you can simply implement your own integer parser, it is not complicated. You can start with this and improve it if needed.
public int parseInt(String s) {
int n = 0;
int pow = 1;
for (int i=s.length() - 1 ; i>=0 ; i--) {
String si = String.valueOf(s.charAt(i);
if (si.matches("[0-9]")) {
n += pow*(s.charAt(i) - '0');
pow *= 10;
} else if (si.matches("+|-") && i == 0)
n *= s.charAt(i) == '+' ? 1 : -1;
else
throw new NumberFormatException();
}
return n;
}
Then, I'll handle the second part of your problem. If Integer.MAX_VALuE is one of your input values, you cannot possibly allocate an Integer.MAX_VALUE x Integer.MAX_VALUE matrix. What you need to do is assign contiguous ids to your input values and record the ids in a map so that you can access easily the index of the matrix corresponding to one node value. Here is an example to get you to understand :
public void someMethod() {
int id = 0;
Map<Integer,Integer> idMap = new HashMap<>();
String[] split = reader.readLine().split(",");
int [] nodes = new int[split.length];
for (int i=0 ; i<nodes.length ; i++) {
nodes[i] = parseInt(split[i]);
if (!idMap.containsKey(nodes[i]))
idMap.put(nodes[i],id++);
}
// the map is now constructed, it should probably be stored in an attribute
int[][] placeholderMatrix = new int[nodes.length][nodes.length];
for(int i = 0; i < nodes.length; i++){
if (i > 0) placeholderMatrix[idMap.get(nodes[i])][idMap.get(nodes[i-1])] = 1;
if (i < nodes.length-1) placeholderMatrix[idMap.get(nodes[i])][idMap.get(nodes[i+1])] = 1;
}
}
There are other ways to do it, let me know if this solution is ok

You could do something like:
String keyword = "1,2,3,4,5,8,7,4";//input line from file
String replacedKeyword = keyword.replaceAll("[^\\d]", "");//except numbers replace all. Assuming one digit numbers only.
String[][] placeholderMatrix = new String[replacedKeyword.length()+1][replacedKeyword.length()+1];
char keys[] = replacedKeyword.toCharArray();
for (int i = 0; i<keys.length - 1; i++) {
placeholderMatrix[keys[i] - '0'][keys[i + 1] -'0'] = "1";
}

I couldn't really understand what you want exactly. but, if that going to help a simple method to convert String number to int:
int toInt(String number) {
int num = 0;
for (int i=0; i<number.length(); i++) {
num = num*10 + (number.charAt(i)-'0');
}
return num;
}

Sqrt, and Math in Arrays

I'm having difficulty understand how to write this array. I need it to out-print 10x5 (50 elements total), and have the first 25 elements equal to the sqrt of the index that it is in, and the last 25 to equal 3 * the index. Yes, this is homework but I'm not asking for you to do it for me, I just need help! I'm getting errors when using Math saying that I cant use double and the double array together. Here is what I have so far:
public class snhu4 {
public static void main(String args[]) {
double alpha[][] = new double[10][5];
double[] sum, sum2;
for (int count=0; count<=25;count++) {
alpha[count]= Math.sqrt(count);
}
for (int count=26; count<=50;count++) {
alpha[count]= count *3;
}
for (int count=0; count<=50;count++) {
System.out.print(alpha[count]);
}
}
}

Because alpha is a multidimensional array, you can't refer to its elements like a normal array.
int myarray[][] = new int[2][2];
In the above example, the array myarray is multidimensional. If I wanted to access the second element in the first array, I would access it like this:
int myint = myarray[0][1];
You are trying to access a multidimensional array by using the access for a normal array. Change
alpha[count]
to
alpha[0][count]
or similar.
Read here for more information on multidimensional arrays.

you defined alpha as a 2D array with lets say 10 items in the first dimension and 5 in the second, and 5x10 is 50 elements.
When using your array to assign values to these elements, u must call upon the array using 2 indices, one for each dimension:
alpha[i][j] = /*double value*/; //with 0<=i<=9 and 0<=j<=4
So the first 25 elements going from left to right in dimension order is going to be:
[0to9][0] and [0to9][1] and [0to4][2]
the next 25 will be
[4to9][2] and [0to9][3] and [0to9][4]
from then on i cannot give you the answers to your homework, but the loops should look like this:
int j;
for(int i = 0; i<25; i++)
{
j=i/10; //integer division will return 0 for i<10, 1 for 10<i<20, etc..
alpha[i%10][j] = Math.sqrt(i);
}
and you can figure out the rest

The 10x5 appears to be an output constraint, not a design constraint.
You are using Java, so use Java constructs, not C-language constructs;
specifically store the values in a List not an array.
Here are some hints:
List<Integer> valuesList = new ArrayList<Integer>();
for (int index = 0; index < 25; ++index)
Integer currentValue = Math.sqrt(index);
valuesList.add(currentValue);
for (int index = 25; index < 50; ++index)
Integer currentValue = index * 3;
valuesList.add(currentValue)
int count = 1;
for (Integer current : valuesList)
if ((count % 5) == 0) // write a newline.
System.out.print(current);
++count