I have an array in Java.
// original array
int[] arr = {1, 2, 3, 4};
How do I get another array that has the duplicated elements of the original array next to the original elements n number of times like so...
// n = 2
int[] arr2 = {1, 1, 2, 2, 3, 3, 4, 4};
// n = 3
int[] arr3 = {1, 1, 1, 2, 2, 2, 3, 3, 3, 4, 4, 4};
You can use streams :)
int[] result = Arrays.stream(arr)
.flatMap(x -> IntStream.range(0, n).map(e -> x))
.toArray();
Because this looks like a homework requirement, you are not likely to be allowed to use streams, so here's a solution with for loops:
int[] result = new int[arr.length * n];
for (int i = 0 ; i < result.length ; i++) {
result[i] = arr[i / n];
}
.flatMap(x -> IntStream.range(0, n).map(e -> x)) may avoid the infinite stream + limit
If using loops is fine,
int origArr = {1,2,3,4};
int[] newArr = new int[n*origArr.length]; // default initialized with zero in Java
int i=0; // loop over new array
int j=0; // loop over original array
while(j<origArr.length){
for(int k=0; k<n; k++){
newArr[i] = origArr[j];
i++;
}
j++;
}
Integer[]also be acceptable?