How to get slice of a Primitive Array in Java
Given a Primitive Array, the task is to get a Slice of this array in Java, using start and ending index.
Examples:
Input: arr[] = {1, 2, 3, 4, 5}, startIndex = 2, endIndex = 4 Output: {3, 4, 5} Input: arr[] = {1, 2, 3, 4, 5}, startIndex = 0, endIndex = 1 Output: {1, 2}
- Method 1: Naive Method.
- Get the Array and the startIndex and the endIndex.
- Create and empty primitive array of size endIndex-startIndex.
- Copy the elements from startIndex to endIndex from the original array to the slice array.
- Return or print the slice of the array.
Below is the implementation of the above approach:
// Java program to Get a Slice
// of a Primitive Array
import
java.util.Arrays;
class
GFG {
// Function to get slice of a primitive array in Java
public
static
int
[] getSliceOfArray(
int
[] arr,
int
start,
int
end)
{
// Get the slice of the Array
int
[] slice =
new
int
[end - start];
// Copy elements of arr to slice
for
(
int
i =
0
; i < slice.length; i++) {
slice[i] = arr[start + i];
}
// return the slice
return
slice;
}
public
static
void
main(String[] args)
{
// Get the array, startIndex and endIndex
int
[] arr = {
1
,
2
,
3
,
4
,
5
};
int
start =
2
, end =
4
;
// Get the slice of the array
int
[] slice = getSliceOfArray(arr, start, end +
1
);
// Print the slice of the array
System.out.println(Arrays.toString(slice));
}
}
chevron_rightfilter_noneOutput:[3, 4, 5]
- Method 2: Using Arrays.copyOfRange() method.
- Get the Array and the startIndex and the endIndex.
- Get the slice using Arrays.copyOfRange() method.
- Return or print the slice of the array.
Below is the implementation of the above approach:
// Java program to Get a Slice
// of a Primitive Array
import
java.util.Arrays;
class
GFG {
// Function to get slice of a primitive array in Java
public
static
int
[] getSliceOfArray(
int
[] arr,
int
startIndex,
int
endIndex)
{
// Get the slice of the Array
int
[] slice = Arrays
.copyOfRange(
// Source
arr,
// The Start index
startIndex,
// The end index
endIndex);
// return the slice
return
slice;
}
public
static
void
main(String[] args)
{
// Get the array, startIndex and endIndex
int
[] arr = {
1
,
2
,
3
,
4
,
5
};
int
start =
2
, end =
4
;
// Get the slice of the array
int
[] slice = getSliceOfArray(arr, start, end +
1
);
// Print the slice of the array
System.out.println(Arrays.toString(slice));
}
}
chevron_rightfilter_noneOutput:[3, 4, 5]
- Method 3: Using Java 8 Streams
- Get the Array and the startIndex and the endIndex.
- Convert the specified range of elements from the startIndex to endIndex to Primitive Stream using range() method.
- Map the specified elements from the original array using map() method.
- Convert the mapped array into array using toArray() method.
- Return or print the slice of the array.
Below is the implementation of the above approach:
// Java program to Get a Slice
// of a Primitive Array
import
java.util.Arrays;
import
java.util.stream.IntStream;
class
GFG {
// Function to get slice of a primitive array in Java
public
static
int
[] getSliceOfArray(
int
[] arr,
int
startIndex,
int
endIndex)
{
// Get the slice of the Array
int
[] slice = IntStream
// Convert the specified elements
// of array into IntStream
.range(startIndex, endIndex)
// Lambda expression to get
// the elements of IntStream
.map(i -> arr[i])
// Convert the mapped elements
// into the slice array
.toArray();
// return the slice
return
slice;
}
public
static
void
main(String[] args)
{
// Get the array, startIndex and endIndex
int
[] arr = {
1
,
2
,
3
,
4
,
5
};
int
start =
2
, end =
4
;
// Get the slice of the array
int
[] slice = getSliceOfArray(arr, start, end +
1
);
// Print the slice of the array
System.out.println(Arrays.toString(slice));
}
}
chevron_rightfilter_noneOutput:[3, 4, 5]
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