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List of type of custom class into array list of integers

Posted on 2011-03-21
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Last Modified: 2012-06-21
I have an array list that containts variables of type of a custom class.
List<List<Point>> points = new ArrayList<List<Point>>();
I would like to convert it into an array list of integers. How to do it?
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Question by:chudyksg
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4 Comments
 
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Expert Comment

by:CEHJ
ID: 35180016
You mean List<List<Integer>>  ?
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LVL 86

Expert Comment

by:CEHJ
ID: 35180041
... or do you mean

List<Integer> ?
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Accepted Solution

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CEHJ earned 500 total points
ID: 35180107
(Assuming the latter)
public List<Integer> pointsToIntegerList(List<List<Point>> points) {
        List<Integer> ints = new ArrayList<Integer>();

        for (List<Point> lp : points) {
            for (Point p : lp) {
                ints.add(p.x);
                ints.add(p.y);
            }
        }

        return ints;
    }

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LVL 1

Expert Comment

by:HyMaX_2003
ID: 35180146
The Point class has two fields called "x" and "y", that represents your point's coordinates. My suggestion is to iterate through all the points and, as the process goes by, create a new array with the "x" and "y" values. So, your final array will be something like { x1, y1, x2, y2, x3, y3 ... }. A sample code to do it:

List<Point> points = new ArrayList<Point>();
List<Integer> points2 = new ArrayList<Integer>();

for (int i = 0; i < points.size(); i++)
{
    points2.add(points[i].x);
    points2.add(points[i].y);
}

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