Java copy section of array [duplicate]

Question

Is there a method that will copy a section of an array(not arraylist) and make a new array from it?

Example:
[1,2,3,4,5]

and you create a new array from it:

[1,2,3]

Are there any one line/methods that will do this?

Marabelle

Answer 1

Here's a java 1.4 compatible 1.5-liner:

int[] array = { 1, 2, 3, 4, 5 };
int size = 3;

int[] part = new int[size];
System.arraycopy(array, 0, part, 0, size);

You could do this in one line, but you wouldn't have a reference to the result.

To make a one-liner, you could refactor this into a method:

private static int[] partArray(int[] array, int size) {
    int[] part = new int[size];
    System.arraycopy(array, 0, part, 0, size);
    return part;
}

then call like this:

int[] part = partArray(array, 3);

Marimaria

Answer 2

See the method Arrays.copyOfRange

Adiana

Answer 3

There is a pre-existing method in the java.util.Arrays: newArray = Arrays.copyOfRange(myArray, startindex, endindex). Or you could easily write your own method:

public static array[] copyOfRange(array[] myarray, int from, int to) {
    array[] newarray = new array[to - from];
    for (int i = 0 ; i < to - from ; i++) newarray[i] = myarray[i + from];
    return newarray;
}

Slip

Answer 4

int [] myArray = [1,2,3,4,5];

int [] holder = new int[size];

System.arraycopy(myArray,0,holder,size);

where 0 stands for the index of source array from where copying should start. and

size stands for the number of copy operations. That you can changes according to your need.

copyOfRange of Arrays is there and many other ways by which this can be accomplished

Roscoeroscommon

You're missing one argument for it requires another int for destinationPosition. – Sham

Answer 5

Arrays#copyOfRange does the trick.

Cramped

Answer 6

As others have stated, you can use Arrays.copyOfRange method. An example is :

String[] main = {"one", "two", "three", "four", "five"};
int from = 2;
int to = 4;
String[] part = Arrays.copyOfRange(main, from, to);

Now part will be : {"two", "three", "four"}

Konstance

There is an error, part is {"three", "four", "five"}, because arrays index starts at 0 – Illiberal