问题
When I run the following code, nothing gets copied - what am I doing wrong?
Also, is this the best/most efficient way to copy data from one array to another?
public class A {
public static void main(String args[]) {
int a[] = { 1, 2, 3, 4, 5, 6 };
int b[] = new int[a.length];
for (int i = 0; i < a.length; i++) {
a[i] = b[i];
}
}
}
回答1:
I think your assignment is backwards:
a[i] = b[i];
should be:
b[i] = a[i];
回答2:
There are lots of solutions:
b = Arrays.copyOf(a, a.length);
Which allocates a new array, copies over the elements of a, and returns the new array.
Or
b = new int[a.length];
System.arraycopy(a, 0, b, 0, b.length);
Which copies the source array content into a destination array that you allocate yourself.
Or
b = a.clone();
which works very much like Arrays.copyOf(). See this thread.
Or the one you posted, if you reverse the direction of the assignment in the loop.
回答3:
Use Arrays.copyOf my friend.
来源：https://stackoverflow.com/questions/6537589/best-way-to-copy-from-one-array-to-another