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.
  1. Get the Array and the startIndex and the endIndex.
  2. Create and empty primitive array of size endIndex-startIndex.
  3. Copy the elements from startIndex to endIndex from the original array to the slice array.
  4. 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));     } }
  Output:

  [3, 4, 5]
  

• Method 2: Using Arrays.copyOfRange() method.
  1. Get the Array and the startIndex and the endIndex.
  2. Get the slice using Arrays.copyOfRange() method.
  3. 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));     } }
  Output:

  [3, 4, 5]
  

• Method 3: Using Java 8 Streams
  1. Get the Array and the startIndex and the endIndex.
  2. Convert the specified range of elements from the startIndex to endIndex to Primitive Stream using range() method.
  3. Map the specified elements from the original array using map() method.
  4. Convert the mapped array into array using toArray() method.
  5. 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));     } }
  Output:

  [3, 4, 5]
  

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