This content originally appeared on DEV Community and was authored by Ogbinaka Emmanuel
So you have two arrays A and B, and you need to copy the elements of A into B. Well there are various ways you can do this in Java and in this post I'll be showing you a couple of ways you can.
Method One : ForLoop
This good old for-loop to the rescue:
int[] A = {1,2,4,4};
int[] B = new int[];
for (int i = 0; i < A.length; i++){
B[i] = A[i];
}
Method Two : .clone()
The clone method of array can help you simply achieve this.
Usage
int[] A = {1,2,4,4};
int[] B = A.clone();//the clone method copies the content of A into B;
Method Three : System.arraycopy()
The next option is to use System.arraycopy() method present in the java.lang package. Before we get into it's usage, let's discuss it's signature:
public static void arraycopy(
Object src, //:source array, in this case A
int srcPos, //:the start index for copy, typically 0
Object dest, //:destination object in this case B.
int destPos, //:the index to place the copied elements
int length //:the length of the contents to be copied
);
Usage
int[] A = {1,2,4,4};
int[] B = new int[];
System.arraycopy(A, 0, B, 0, A.length);
Method Four : Arrays.copyOf()
The next option we'll be discussing is from the Arrays class present in the java.utils package. Once again, let's discuss it's signature:
public static int[] copyOf(
int[] original, // :source array in this case A
int newLength // :the length of the contents to be copied
);
Usage
int[] A = {1,2,4,4};
int[] B = Arrays.copyOf(A, 3);
Method Five : Arrays.copyOfRange()
So, this will be the last option we'll be discussing for this post and from the Arrays class present in the java.utils package. Once again, let's see it's signature:
public static int[] copyOfRange(
int[] original, // :source array in this case A
int from, //:the start index for copy, typically 0
int to // the end index exclusive
);
Usage
int[] A = {1,2,3,4,5,6,7};
int[] B = Arrays.copyOfRange(A, 0, A.length);
This content originally appeared on DEV Community and was authored by Ogbinaka Emmanuel
Ogbinaka Emmanuel | Sciencx (2021-08-09T16:17:35+00:00) How to Copy Array in Java. Retrieved from https://www.scien.cx/2021/08/09/how-to-copy-array-in-java/
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