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
// 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)); } } |
Output
[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
// 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(arr, startIndex, 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)); } } |
Output
[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
// 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)); } } |
Output
[3, 4, 5]
- Method 4: Using System.arraycopy() method.
- Get the Source Array, its startIndex and total no. of components to be copied
- Get the Destination Array and its startIndex
- Get the slice using System.arraycopy() method.
- Return or print the slice of the array.
Syntax:
public static void arraycopy(Object source_arr, int sourcePos, Object dest_arr, int destPos, int len)
Below is the implementation of the above approach:
Java
// Java program to Get a Slice // of a Primitive Array // Using System.arraycopy() 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 len) { // Get the slice of the Array int [] slice = new int [len]; // Slice the original array System.arraycopy(arr, startIndex, slice, 0 , len); // [3, 4, 5] // 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 , len = 3 ; // Get the slice of the array int [] slice = getSliceOfArray(arr, start, len); // Print the slice of the array System.out.println(Arrays.toString(slice)); } } // This code is contributed by Susobhan Akhuli |
Output
[3, 4, 5]
- Method 5: Using List.subList() method.
- Get the Source Array, its startIndex and endIndex to be copied
- Convert the Source Array to ArrayList
- Get the slice using List.subList() method
- Again Convert the Sliced ArrayList to Sliced Array
- Return or print the slice of the array.
Syntax:
public List subList(int fromIndex, int toIndex)
Below is the implementation of the above approach:
Java
// Java program to Get a Slice // of a Primitive Array // Using List.subList() import java.util.Arrays; import java.util.List; import java.util.stream.Collectors; class GFG { // Function to get slice of a primitive array in Java static int [] getSliceOfArray( int [] arr, int fromIndex, int toIndex){ // Conversion of Array To ArrayList List<Integer> ar = Arrays.stream(arr).boxed().collect(Collectors.toList()); // Get the slice of the Original Array List<Integer> arrl = ar.subList(fromIndex, toIndex); // Conversion of ArrayList to Array int [] slice = arrl.stream().mapToInt(i -> i).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 = 5 ; // Get the slice of the array int [] slice = getSliceOfArray(arr, start, end); // Print the slice of the array System.out.println(Arrays.toString(slice)); } } // This code is contributed by Susobhan AKhuli |
Output
[3, 4, 5]
- Method 6: Using Streams API:
- Get the Source Array, its startIndex and total no. of components to be copied
- Get the slice using stream method
- Return or print the slice of the array.
Syntax:
int[] sliced = Arrays.stream(original) .skip(startIndex) .limit(length) .toArray();
Below is the implementation of the above approach:
Java
// Java program to Get a Slice // of a Primitive Array // Using Stream API import java.util.Arrays; import java.util.stream.Collectors; class GFG { // Function to get slice of a primitive array in Java static int [] getSliceOfArray( int [] arr, int startIndex, int len) { // Get the slice of the array int [] slice = Arrays.stream(arr) .skip(startIndex) .limit(len) .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 , len = 3 ; // Get the slice of the array int [] slice = getSliceOfArray(arr, start, len); // Print the slice of the array System.out.println(Arrays.toString(slice)); } } // This code is contributed by Susobhan AKhuli |
Output
[3, 4, 5]
- Method 7: Using ArrayUtils.subarray() Method:
- Get the Source Array, its startIndex and endIndex to be copied
- Get the slice using ArrayUtils.subarray() method
- Return or print the slice of the array.
Syntax:
int[] sliced = ArrayUtils.subarray(Original_array, Start_Index, End_Index);
Below is the implementation of the above approach:
Java
// Java program to Get a Slice // of a Primitive Array // Using ArrayUtils.subarray() Method import java.util.Arrays; import org.apache.commons.lang3.ArrayUtils; class GFG { // Function to get slice of a primitive array in Java static int [] getSliceOfArray( int [] arr, int startIndex, int endIndex) { // Get the slice of the array int [] slice = ArrayUtils.subarray(arr, startIndex, 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 = 5 ; // Get the slice of the array int [] slice = getSliceOfArray(arr, start, end); // Print the slice of the array System.out.println(Arrays.toString(slice)); } } // This code is contributed by Susobhan AKhuli |
Output
[3, 4, 5]
- Method 8: Using Guava library:
- Get the Source Array, its startIndex and length to be copied
- Convert array to list
- Get the slice using Guava library
- convert list to array again
- Return or print the slice of the array.
Syntax:
List<Integer> subList = list.subList(startIndex, startIndex + length);
Below is the implementation of the above approach:
Java
// Java program to Get a Slice // of a Primitive Array // Using Guava library import com.google.common.primitives.Ints; import java.util.Arrays; import java.util.List; class GFG { // Function to get slice of a primitive array in Java static int [] getSliceOfArray( int [] arr, int startIndex, int length) { // convert array to list List<Integer> list = Ints.asList(arr); // Get the slice of the list List<Integer> subList = list.subList(startIndex, startIndex + length); // convert list to array int [] slice = Ints.toArray(subList); // return the slice return slice; } public static void main(String[] args) { // Get the array, startIndex and length of sliced // array int [] arr = { 1 , 2 , 3 , 4 , 5 }; int start = 2 , len = 3 ; // Get the slice of the array int [] slice = getSliceOfArray(arr, start, len); // Print the slice of the array System.out.println(Arrays.toString(slice)); } } // This code is contributed by Susobhan AKhuli |
Output
[3, 4, 5]