你如何传递数组维度？

Question

How do you pass Array dimensions along with the Array in java? I invision something like this:

public String[1][1] abc(){
return theStringArray
}    
//but this isn't possible

So is there a way to pass dimensions of arrays?

Right now I have 2 methods that pass an int for each dimension but is there a better way of doing this?

The problem at it's heart is this:

When I try to pass the array and find it's length, it gives me a load of errors. The problem is that the array for the class receiving the array needs to initialize the array the the passed array will copy to, but without the passed arrays dimensions, how can I initialize it?

Class the array is passed to:

String[][] lordStats;
ArrayList<String> troopList;

public void loader() {
    lord lorder = new lord();
    lordStats = lorder.returnLord();
    total = lorder.returnLordTotal();
for (int i = 0; i < lordStats[0].length; i++)
    troopList.add (lordStats[i][2]);

}

Class the array comes from: note that method lord creator is called multipul times.

public class lord {
static int total;
String[][] lordStats;

public void total(int total1) {
    total = total1;
    System.out.println("lordTotal");

}

public void lordCreator(String lord, String kingdom, String troop, int times) {

    lordStats = new String[total][3];
    System.out.println("animalStats");

    lordStats[times][0] = lord;
    lordStats[times][1] = kingdom;
    lordStats[times][2] = troop;


}

public String[][] returnLord() {
    return lordStats;
}

Answer 1

In Java, you usually don't have to pass array dimensions along with the array, since every array implicitly knows its own dimensions.

If the array is called arr , then arr.length would return its size. If arr is a 2D array, then arr[0].length would give the size of the first row; arr[1].length is the size of the next row, and so on.

If the function is to allocate an array of caller-specified size, simply pass the desired dimensions into the function as int arguments.

Answer 2

You don't have to explicitly pass array dimensions in Java, arrays have length properties for that.

public String[][] abc() {
    return new String[10][10];
}

Answer 3

You can figure out the length of an array with just .length . But Java arrays are just arrays of arrays (not N-dimensional blocks of contiguous elements).

Thus, they can be jagged, meaning each row has a different number of columns. So you can only rely on the length of theStringArray[0] (the column count for the first row) equaling theStringArray[1] if there is a documented understanding that theStringArray is not jagged.

Answer 4

All arrays in Java are 1-dimensional. You can have an array of arrays, which is effectively a 2-dimensional array. However, each element can have a different length and there is no way to enforce a single second dimension size. You can do something like this:

public String[][] makeArray(int rows, int columns) {
    return new String[rows][columns];
}

Then you can query the array as follows:

String[][] array = makeArray(1, 1);
System.out.println("Row count: " + array.length);
System.out.println("Column count: " + array[0].length); // assumes >0 elements

However, someone could do this:

String[][] array = makeArray(3, 3);
array[0] = new String[1];

The previous code would then give a misleading result for the number of columns.