I need a method that given input 2D array {{1,2},{3,4}} and (int)row=2; (int)column = 3, will produce a concatenated 2D array {{1,2,1,2,1,2}{3,4,3,4,3,4}}.
My attempt was to use a nested for loop to expand them both horizontally and and vertically, but was unsuccessful. This is what I have so far:
int row = 2;
int column = 5;
int count = 0;
int[][] list = {{12,3},{3,4}};
int [][] renewed = new int[row*list.length][column*list[0].length];
for (int l = 0; l<list.length; l++) {
for (int k = 0; k<renewed.length; k+= list.length) {
renewed[l+k] = list[l];
}
}
System.out.println(Arrays.deepToString(renewed));
}
}
^This produces list[][] expanded vertically, for the first column
int row = 2;
int column = 4;
int[][] list = {{12,3},{3,4}};
int [][] renewed = new int[row*list.length][column*list[0].length];
for (int i = 0; i<list[0].length; i++) {
for (int j = 0; j<renewed[0].length; j+=list[0].length) {
renewed[0][j+i] = list[0][i];
}
}
System.out.println(Arrays.toString(renewed[0]));
}
^This produces list[][] expanded horizontally, for the first row;
So how can I concatenate these two methods in order to produce a method that expands BOTH horizontally and vertically?
I think the easiest way is to iterate over every position in the new array and use the remainder operator % to get the right entry of the original.
int[][] list = {{1,2},{3,4}};
int row = 2;
int column = 5;
int [][] renewed = new int[row*list.length][column*list[0].length];
for (int i = 0; i < renewed.length; i++) {
for (int j = 0; j < renewed[0].length; j++) {
renewed[i][j] = list[i % list.length][j % list[0].length];
}
}
System.out.println(Arrays.deepToString(renewed));
Related
String[] dizi_paragraf = dosya.split("\n");
for (int i = 0; i < dizi_paragraf.length; i++) {
String[] dizi_cumle = dizi_paragraf[i].split("\\.");
String[][] dizi_total = new String[dizi_paragraf.length][dizi_cumle.length];
int[][] dizi = new int[dizi_paragraf.length][dizi_cumle.length];
for (int j = 0; j < dizi_cumle.length; j++) {
dizi_total[i][j] = dizi_cumle[j];
dizi[i][j] = j;
System.out.println(dizi[i][j]);
}
}
Output:
0-0
0-1
1-0
1-1
1-2
2-0
3-0
3-1
4-0
4-1
5-0
5-1
5-2
5-3
I want this:
0-1
0-0
1-1
1-0
1-2
2-0
3-1
3-0
4-0
4-1
5-3
5-1
5-0
5-2
This is an example.
The value in j for each i changes randomly but until j length.
How can I do this? Have you any ideas?
For example, it should produce 0 or 1 for index 0. It should produce 0.1 or 2 for the 1st index. 2. You should take only 0 for indis. etc.
Just example. This can be change. I take this dynamically.
"i" must be constant. But j should be chosen randomly. for indice 0, j value: 0 and 1. This should be chosen randomly. for indice 1, j value: 0,1 and 2. This should be chosen randomly.
Try something as below:
String dosya = "Test cumle 1. CUmle 2.\nCumle 3 here. Next sentences. Last sentences.";
String[] dizi_paragraf = dosya.split("\n");
for (int i = 0; i < dizi_paragraf.length; i++) {
String[] dizi_cumle = dizi_paragraf[i].split("\\.");
String[][] dizi_total = new String[dizi_paragraf.length][dizi_cumle.length];
int[][] dizi = new int[dizi_paragraf.length][dizi_cumle.length];
List<Integer> jj = new ArrayList<>();
for (int j = 0; j < dizi_cumle.length; j++) {
jj.add(j);
}
Collections.shuffle(jj);
for (int j:jj) {
dizi_total[i][j] = dizi_cumle[j];
dizi[i][j] = j;
System.out.println("dizi[i][j] "+i+"-"+j);
}
}
The following solution does not use Collection.shuffle, just Random generator and arrays.
String[] dizi_paragraf = dosya.split("\n");
Random r = new Random();
for (int i = 0; i < dizi_paragraf.length; i++) {
String[] dizi_cumle = dizi_paragraf[i].split("\\.");
String[][] dizi_total = new String[dizi_paragraf.length][dizi_cumle.length];
int[][] dizi = new int[dizi_paragraf.length][dizi_cumle.length];
for (int j = 0; j < dizi_cumle.length; j++) {
int rNumber = 0;
boolean unique=false;
while (!unique){
unique=true;
rNumber = r.nextInt(dizi_cumle.length);
for (int jj = 0; jj < j; jj++) {
if (dizi[i][jj] == rNumber) {
unique = false;
break;
}
}
}
dizi_total[i][j] = dizi_cumle[j];
dizi[i][j] = rNumber;
System.out.println(i + "-" + dizi[i][j]);
}
}
For each j, the while loops starts with unique=false. It gets a random number r.nextInt(dizi_cumle.length) and sets the unique to true. Then it does a for loop on the dizi[][] array on the second dimension j, until it finds a previously set number. If the for loop ends without entering the if (dizi[i][jj] == rNumber) the unique is never set to false and the while exits. The number finally is set into the array.
I have this line of code to create a zigzag array, its fairly simple and I already have the code for it. here's the summary of the question:
This method creates and returns a new two-dimensional integer array, which in Java is really just a one-dimensional array whose elements are one-dimensional arrays of type int[]. The returned array must have the correct number of rows that each have exactly cols columns. This array must contain the numbers start, start + 1, ..., start + (rows * cols - 1) in its rows in order, except that the elements in each odd-numbered row must be listed in descending order.
For example, when called with rows = 4, cols = 5 and start = 4, this method should create and return the two-dimensional array whose contents are
4 5 6 7 8
13 12 11 10 9
14 15 16 17 18
23 22 21 20 19
I've tried talking with my colleagues but they can't spot the problem too
public class P2J1
{
public static int[][] createZigZag(final int rows, final int cols, int start)
{
final int[][] array = new int[rows][cols];
for (int i = 0; i < rows; i++)
{
for (int j = 0; j < cols; j++)
{
array[i][j] = start;
start++;
}
}
return array;
}
}
/// heres the tester program
#Test public void testCreateZigZag() {
Random rng = new Random(SEED);
CRC32 check = new CRC32();
for(int i = 0; i < TRIALS; i++) {
int rows = rng.nextInt(20) + 1;
int cols = rng.nextInt(20) + 1;
int start = rng.nextInt(100);
int[][] zig = P2J1.createZigZag(rows, cols, start);
assertEquals(rows, zig.length);
for(int j = 0; j < rows; j++) {
assertEquals(cols, zig[j].length);
for(int e: zig[j]) { check.update(e); }
}
}
assertEquals(3465650385L, check.getValue());
}
Your column index always goes from 0 to cols-1, in that order. You need to alternate the order every other row.
You can do this by using variables for the start, end, and increment of the inner loop and assign those variables based on the row index being odd or even.
Something like this (untested):
public static int[][] createZigZag(final int rows, final int cols, int start) {
final int[][] array = new int[rows][cols];
for (int i = 0; i < rows; i++) {
boolean backwards = ((i & 1) == 1);
final int jStart = backwards ? cols-1 : -1;
final int jEnd = backwards ? 0 : cols;
final int jStep = backwards ? -1 : 1;
for (int j = jStart; j != jEnd; j += jStep) {
array[i][j] = start;
start++;
}
}
return array;
}
You could also just write two different inner loops, selected on the same condition. One would fill starting from 0, the other would fill starting from cols-1 and going backwards.
public static int[][] createZigZag(final int rows, final int cols, int start) {
final int[][] array = new int[rows][cols];
for (int i = 0; i < rows; i++) {
if ((i & 1) == 1) {
for (int j = cols-1; j >= 0; j--) {
array[i][j] = start;
start++;
}
} else {
for (int j = 0; j < cols; j++) {
array[i][j] = start;
start++;
}
}
}
return array;
}
I am attempting to solve a semi-difficult problem in which I am attempting to create an array and return a 3 dimensional array based on the parameter which happens to be a 2 dimensional int array. The array I'm attempting to return is a String array of 3 dimensions. So here is the code:
public class Displaydata {
static String[][][] makeArray(int[][] dimensions) {
String myArray[][][];
for (int i = 0; i < dimensions.length; i++) {
for (int j = 0; j < dimensions[i].length; j++) {
myArray[][][] = new String[i][j][]; //getting error here.
}
}
return myArray;
}
static void printArray(String[][][] a) {
for (int i = 0; i < a.length; i++) {
System.out.println("\nrow_" + i);
for (int j = 0; j < a[i].length; j++) {
System.out.print( "\t");
for (int k = 0; k < a[i][j].length; k++)
System.out.print(a[i][j][k] + " ");
System.out.println();
}
}
}
public static void main(String[] args) {
int [][] dim = new int[5][];
dim[0] = new int[2];
dim[1] = new int[4];
dim[2] = new int[1];
dim[3] = new int[7];
dim[4] = new int[13];
dim[0][0] = 4;
dim[0][1] = 8;
dim[1][0] = 5;
dim[1][1] = 6;
dim[1][2] = 2;
dim[1][3] = 7;
dim[2][0] = 11;
for (int i = 0; i < dim[3].length;i++)
dim[3][i] = 2*i+1;
for (int i = 0; i < dim[4].length;i++)
dim[4][i] = 26- 2*i;
String[][][] threeDee = makeArray(dim);
printArray(threeDee);
}
}
As you can see from the source code, I'm getting an error when I try to create an instance of my 3-dimensional array which I'm attempting to return. I'm supposed to create a three dimensional array with the number of top-level rows determined by the length of dimensions and, for each top-level row i, the number of second-level rows is determined by the length of dimensions[i]. The number of columns in second-level row j of top-level row i is determined by the value of dimensions[i][j]. The value of each array element is the concatenation of its top-level row index with its second-level row index with its column index, where indices are represented by letters : ‘A’ for 0, ‘B’ for 1 etc. (Of course, this will only be true if the indices don’t exceed 25.) I don't necessarily know where I'm going wrong. Thanks!
You should not be initializing the array on every iteration of the loop. Initialize it once outside the loop and then populate it inside the loop.
static String[][][] makeArray(int[][] dimensions) {
String[][][] myArray = new String[25][25][1];
for (int i = 0; i < dimensions.length; i++) {
for (int j = 0; j < dimensions[i].length; j++) {
myArray[i][j][0] = i + "," + j;
}
}
return myArray;
}
I just plugged in values for the size of the first two dimensions, you will need to calculate them based on what you put in there. The 'i' value will always be dimensions.length but the 'j' value will be the largest value returned from dimensions[0].length -> dimensions[n-1].length where 'n' is the number of elements in the second dimension.
Also you will need to set up a way to convert the numbers in 'i' and 'j' to letters, maybe use a Map.
I guess you should initialize the array as
myArray = new String[i][j][]; //getting error here.
I think
myArray[][][] = new String[i][j][]; //getting error here.
should be:
myArray[i][j] = new String[5]; // I have no idea how big you want to go.
And then you can fill in each element of you inner-most array like such:
myArray[i][j][0] = "first item";
myArray[i][j][1] = "second string";
...
I think you should just change that line to:
myArray = new String[i][j][]; //look ma! no compiler error
Also, you would need to initialize myArray to something sensible (perhaps null?)
How can I get int a = 400; int b = 100; from 2-dimensional array 1000 x 1000 in Java, for example, mass[400][100] (row 400, column 100)? I found element in array and need numbers of his row/line and column. How can I get this numbers? Thanks.
Are you asking how to get the dimensions of an array?
If a is new int[400][100]; then you can get 400 by doing a.length and 100 by doing a[0].length.
If you need to find the position in the array based on the value, you have no other option but to brute-force loop through the whole array, breaking out when you find the first match:
int[][] massiveArray = new int[1000][1000];
final int valueTofind = 27;
// assign the value to find at position (400, 100)
massiveArray[400][100] = valueTofind;
int i_value = -1;
int j_value = -1;
// find the first occurrance of valueTofind by looping through the array
outer: for (int i = 0; i < massiveArray.length; i++) {
for (int j = 0; j < massiveArray[0].length; j++) {
if (massiveArray[i][j] == valueTofind) {
i_value = i;
j_value = j;
break outer;
}
}
}
System.out.println(String.format("First position for %d is at (%d, %d)",
valueTofind, i_value, j_value));
you can Work Around this .. To get a value in 2d array one way to do is
int[][] a = ...;
for (int r=0; r < a.length; r++) {
for (int c=0; c < a[r].length; c++) {
int value= a[r][c];
}
}
hi I'm having a little problem with arrays.
here's the code:
int frame_size = 410;
int frame_shift = 320;
ArrayList<double[]> frames = new ArrayList<double[]>();
for (int i = 0; i + frame_size < inbuf.length; i = i + frame_shift) {
double[] frame = new double[frame_size];
System.arraycopy(inbuf, i, frame, 0, frame_size);
frames.add(frame);
}
here I share a large array into several small, and add them to arraylist
I need to get more of ArrayList arrays and pass them to the function, and then accept the answer and assemble arrays processed one:
int[] Cover = new int[frames.size() * nParam];
for (int i = 0; i < frames.size(); i++) {
double[] finMc = Gos.getVek(frames.get(i));
for (int c = 0; c < finMc.length; c++) {
int mc = (int) finMc[c];
for (int m = 0; m < Cover.length; m++) {
Cover[m] = mc;
}
}
}
all this code does not work (
all elements of the array are zero Cover.
Сover[0] = 0
Cover[1] = 0
Cover[2] = 0
...
help solve the problem, please!)
thank you in advance)
Update
int frame_size = 410;
int frame_shift = 320;
ArrayList<double[]> frames = new ArrayList<double[]>();
for (int i = 0; i + frame_size < inbuf.length; i = i + frame_shift) {
double[] frame = new double[frame_size];
System.arraycopy(inbuf, i, frame, 0, frame_size);
frames.add(frame);
}
int[] Cover = new int[frames.size() * nParam];
for (int i = 0; i < frames.size(); i++) {
double[] finMc = Gos.getVek(frames.get(i));
for (int c = 0; c < finMc.length; c++) {
int mc = (int) finMc[c];
Cover[i * frames.size() + c] = (int) finMc[c];
}
}
Code^ not work(
UPDATE 2
double[] inbuf = new double[Size];
inbuf = toDoubleArray(Gos.data);
inbuf[2] = 10;
inbuf[4] = 14;
toDoubleArray
public static double[] toDoubleArray(byte[] byteArray) {
int times = Double.SIZE / Byte.SIZE;
double[] doubles = new double[byteArray.length / times];
for (int i = 0; i < doubles.length; i++) {
doubles[i] = ByteBuffer.wrap(byteArray, i * times, times)
.getDouble();
}
return doubles;
}
Code not work:
int frame_size = 410;
int frame_shift = 320;
ArrayList<double[]> frames = new ArrayList<double[]>();
for (int i = 0; i + frame_size < inbuf.length; i = i + frame_shift) {
double[] frame = new double[frame_size];
System.arraycopy(inbuf, i, frame, 0, frame_size);
frames.add(frame);
}
double[] Cover = new double[frames.size() * nParam];
for (int i = 0; i < frames.size(); i++) {
double[] finMc = Gos.getVek(frames.get(i));
for (int c = 0; c < finMc.length; c++) {
Cover[i * frames.size() + c] = finMc[c];
}
}
A couple of thoughts spring to mind immediately:
1)
for (int m = 0; m < Cover.length; m++) {
Cover[m] = mc;
}
This block starts m over at 0 every time through the loop. This means you're always writing over the same portion of the Cover array. So effectively, it's only the last frame's data that's stored. You probably meant
for(int m = i * frames.size(); m < (i+1)*frames.size(); i++) {
Cover[m] = mc;
}
But this raises a further issue -- you're writing the same value (mc) into the entire area allocated for a whole frame of data. You probably want to merge this loop with the previous loop so that this doesn't happen.
for (int c = 0; c < finMc.length; c++) {
Cover[i * frames.size() + c] = (int)finMc[c];
}
2) int mc = (int) finMc[c];
That line casts the value to an int which truncates the value stored at finMc[c]. If finMc[c] is between 0 and 1 this will yield 0 when the data is copied and casted. This is compounded by the previous issue which ensures that only the last frame's data ever gets copied. This is simply solved by removing the cast and declaring Cover as an array of doubles instead of ints.
So in sum, the code might work a bit better if it's written this way:
double[] Cover = new double[frames.size() * nParam];
for (int i = 0; i < frames.size(); i++) {
double[] finMc = Gos.getVek(frames.get(i));
for (int c = 0; c < finMc.length; c++) {
Cover[i * frames.size() + c] = finMc[c];
}
}