How to create a sub array from another array in Java?

Question

How to create a sub-array from another array? Is there a method that takes the indexes from the first array such as:

methodName(object array, int start, int          


        

Answer 1

Using Apache ArrayUtils downloadable at this link you can easy use the method

subarray(boolean[] array, int startIndexInclusive, int endIndexExclusive) 

"boolean" is only an example, there are methods for all primitives java types

Answer 2

Use copyOfRange method from java.util.Arrays class:

int[] newArray = Arrays.copyOfRange(oldArray, startIndex, endIndex);

For more details:

Link to similar question

Answer 3

You can use

JDK > 1.5

Arrays.copyOfRange(Object[] src, int from, int to)

Javadoc

JDK <= 1.5

System.arraycopy(Object[] src, int srcStartIndex, Object[] dest, int dstStartIndex, int lengthOfCopiedIndices); 

Javadoc

Answer 4

int newArrayLength = 30; 

int[] newArray = new int[newArrayLength];

System.arrayCopy(oldArray, 0, newArray, 0, newArray.length);

Answer 5

Yes, it's called System.arraycopy(Object, int, Object, int, int) .

It's still going to perform a loop somewhere though, unless this can get optimized into something like REP STOSW by the JIT (in which case the loop is inside the CPU).

int[] src = new int[] {1, 2, 3, 4, 5};
int[] dst = new int[3];

System.arraycopy(src, 1, dst, 0, 3); // Copies 2, 3, 4 into dst

Answer 6

I you are using java prior to version 1.6 use System.arraycopy() instead. Or upgrade your environment.