For example: double [string] data; double [200][1000] data2; for(int i = 0; i < 200; i++) { for(int j = 0; j < 1000; j++) { // fake multi-dim works string str = to!string(i) ~ "," ~ to!string(j); data[str] = someNumber; // real multi-dim does not work data2[i][j] = someNumber; } }