In python we are able to do the following:
array = [0,1,2,3,4,5,6,7,8,9,10]
new_array= array[::3]
print(new_array)
>>>[0,3,6,9]
Is there an equivalent to this in Java? I have been looking for this type of array slicing, but I have had no luck. Any help would be great, Thanks!
If you are using Java 8, then you can make use of streams and do the following:
int [] a = new int [] {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
// filter out all indices that evenly divide 3
int [] sliceArr = IntStream.range(0, a.length).filter(i -> i % 3 == 0)
.map(i -> a[i]).toArray();
System.out.println(Arrays.toString(sliceArr));
Outputs: [0, 3, 6, 9]
There is a method in Arrays that might help.
int[] newArr = Arrays.copyOfRange(arr, 5,10);
It is obviously far less powerful the the python implementation.
Java has no built-in mechanism for this. You could write a helper function:
public static int[] sliceArray(int[] arr, int spacing) {
int curr = 0;
int[] newArr = new int[((arr.length - 1) / spacing) + 1];
for (int i = 0; i < newArr.length; ++i) {
newArr[i] = arr[curr];
curr += spacing;
}
return newArr;
}
Note that Michael's answer is better (or at least less verbose) if you can utilize Java 8.
We can simply loop over array and collect values on every step
public static <T> List<T> sliceArray(List<T> arr,int start, int stop ,int step){
System.out.println("slice with step initial = " + arr);
List<T> res = new ArrayList<T>();
for(int i=0;i<arr.size();i++){
if(i%step==0) res.add(arr.get(i));
}
return res;
}
