Let's say I have an array:
int[] values = {1, 2, 3, 4, 5, 6, 7 , 8, 9, 0};
With two indexes (let's say 2 and 5), I want to be able to return array from indexes 2 to 5 from the variable values given above. The final output should be this:
newValues[] = {3, 4, 5, 6};
Also, how would this procedure be used with multi dimensional arrays?
I would have googled this, but I'm not sure what to google, so I came here.
Use java.util Arrays class. Use copyOfRange(int[] original, int from, int to) method:
newValues[] = Arrays.copyOfRange(values, 2, 6);
Try the following
public static void main(String[] args)
{
int[] values = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 0 };
int start = 2, end = 5; // Index
int[] newValues = new int[end - start + 1]; // Create new array
for (int i = start; i <= end; i++) {
newValues[i - start] = values[i]; // Assign values
}
// Print newValues
for (int v : newValues) {
System.out.print(v + " ");
}
}
Output:
3 4 5 6
Try the following for 2D arrays:
public int[][] getRange(int[][] src, int x, int y, int x2, int y2) {
int[][] ret = new int[x2-x+1][y2-y+1];
for(int i = 0; i <= x2-x; i++)
for(int j = 0; j <= y2-y; j++)
ret[i][j] = src[x+i][y+j];
return ret;
}
For 1D Arrays, Arrays.copyOfRange() should be fine and for more dimensions you can simply add more params and for loops
Arrays.copyOfRange() for multi-dimensional arrays?You can use the following :
int[] values = {1, 2, 3, 4, 5, 6, 7 , 8, 9, 0};
int newValues[] = new int[4];
System.arraycopy(values,1,newValues,0,4)
Here's the complete code :
public class CopyRange {
public static void main (String...args){
int[] values = {1, 2, 3, 4, 5, 6, 7 , 8, 9, 0};
int newValues[] = new int[4];
System.arraycopy(values,1,newValues,0,4);
for (int i =0;i <newValues.length;i++)
System.out.print(newValues[i] + " ");
}
}
The System class has an arraycopy method that you can use to efficiently copy data from one array into another:
public static void arraycopy(Object src, int srcPos, Object dest, int destPos, int length)
Arrays.copyOfRange(original, from, to)toindex is excluded in result array so you will have to correct it with +1.