CODEWITHSUNDEEP
javaarrays
LunaVulpo
LunaVulpo

Reputation: 3221

How divide 2d array into 1d array by one statement?

If I have:

int[] a = {1,2,3,4,5};
int[] b = {5,7,8,9};
int[][] array2d ={a,b};

I can divide array2d into 2 1d array by:

int[] A = new int[array2d[0].length];
int[] B = new int[array2d[1].length];
for(int i = 0; i < array2d.lenght; i++){
   A[i] = array2d[i][0];
   B[i] = array2d[i][1];
}

but can it be done by one statement?

For example if I have:

int[][] array2dx = new int[2][1000];

I can do easy:

int[] Ax = array2dx[0];
int[] Bx = array2dy[1];

So I am look for something similar (dividing into 2 arrays) for array int[1000][2];

Upvotes: 1

Views: 1682

Answers (1)

Jon Skeet
Jon Skeet

Reputation: 1502086

but can it be done by one statement?

Not with any built-in methods that I'm aware of. It sounds like you basically want to write a transpose method though:

 static int[][] transpose(int[][] input) {
     // TODO: Validation. Detect empty and non-rectangular arrays.
     int[][] ret = new int[input[0].length][];
     for (int i = 0; i < ret.length; i++) {
        ret[i] = new int[input.length];
     }
     for (int i = 0; i < input.length; i++) {
         for (int j = 0; i < ret.length; j++) {
             ret[j][i] = input[i][j];
         }
     }
     return ret;
 }

Once you've transposed an int[1000][2] into an int[2][1000] you can get the two int[1000] arrays out simply, as you've already shown.

Upvotes: 1

Related Questions