Java ArrayList<Object[]> to Object[][]

Question

I have data in the format

List<Object[]> data = new ArrayList<Object[]>();

for(Something s : SomeList) {
    Object[] tempList = { s.test, s.test2, s.test3 };

    data.add(tempList);
}

So I have an ArrayList of Objects[]. Now I want to get that ArrayList of objects into an Object[][] so I have the data in the format

Object[][] data = { { test, test2, test3 }, { test4, test5, test6 } };

but I'm not sure how to do that.

The ArrayList step isn't important, it's just the direction I took when trying to figure it out. If you have a better way of getting the data to Object[][] that's great.

@mdoran3844 - Incorrect. for(Something s : someList) iterates over each item in a List or Array. s.test and s.test2 represent the properties of each successive item in the list. — jahroy
– jahroy, Commented Aug 23, 2013 at 0:50

arshajii · Accepted Answer · 2013-08-23 14:14:56Z

9

You can use List#toArray(T[]):

Object[][] array = data.toArray(new Object[data.size()][]);

edited Aug 23, 2013 at 14:14

answered Aug 23, 2013 at 0:33

arshajii

130k26 gold badges246 silver badges293 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

jahroy Over a year ago

Cheers to the pleasant surprises waiting to be discovered when one reads the documentation... I was a little surprised that this would work, but I just tested it and it works great. +1

ningyuwhut · Accepted Answer · 2013-08-23 00:41:07Z

1

Object[][] data2 = new Object[data.size()][]
for( int i = 0; i < data.size(); ++i)
{
    data2[i] = new Object[data.get(i).length];
    for( int j = 0; j < data.get(i).length; ++j )
    {
        data2[i][j] = data.get(i)[j];
    }
}

answered Aug 23, 2013 at 0:41

ningyuwhut

63913 silver badges30 bronze badges

Collectives™ on Stack Overflow

Java ArrayList<Object[]> to Object[][]

2 Answers 2

1 Comment

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

1 Comment

Comments

Your Answer

Sign up or log in

Post as a guest

Related