如何过滤Java中的数组？ [英] How to filter an array in Java?

问题描述

我如何在Java过滤器的阵列？

How can I filter an array in Java?

我有对象的数组，例如汽车：

I have an array of objects, for example cars:

类：

public class Car{
    public int doors;
    public Car(int d){
        this.doors = d;
    }
}

使用：

Car [] cars = new Cars[4];
cars[0] = new Car(3);
cars[1] = new Car(2);
cars[2] = new Car(4);
cars[3] = new Car(6);

现在我想汽车的阵列进行筛选，只保留4门多：

Now I want to filter the array of cars, keeping only 4 doors and more:

for(int i = 0; i<cars.length; i++){
    if(cars[i].doors > 4)
         //add cars[i] to a new array
    }
}

我应该怎么做呢？

How should I do this?

在我的Vector做到了：

Before I did it with a Vector:

Vector subset = new Vector();
for(int i = 0; i<cars.length; i++){
    if(cars[i].doors > 4)
         //add cars[i] to a new array
        subset.addElement(cars[i]);
    }
}

然后我会做与向量的大小的新数组。然后，我会遍历所有的矢量再次填充新数组。我知道这是一些简单的一个非常大的过程。

And then I would make a new array with the size of the Vector. Then I would loop over the vector again and fill the new array. I know this is a very large procedure for something simple.

的我使用J2ME。的

推荐答案

编辑：看到ArrayList是不是在J2ME的，但基于文档，它有一个载体。如果Vector类比J2SE载体不同（如这个文件表明 ），那么也许下面的code将工作：

saw that ArrayList is not in J2ME, but based on documentation, it does have a Vector. If that Vector class is different than J2SE Vector (as this documentation indicates), then perhaps the following code would work:

Vector carList = new Vector();
for(int i = 0; i<cars.length; i++){
    if(cars[i].doors > 4)
         carList.addElement(cars[i]);
    }
}
Car[] carArray = new Car[carList.size()];
carList.copyInto(carArray);

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