【问题标题】:Java print arraylist numberedJava打印arraylist编号
【发布时间】:2015-03-20 23:30:03
【问题描述】:

我有这个

public String toString()
{
        return "a " + year + " " +  make + " " + model +
                " with a VIN# of " + vin + " and a mileage of " + miles;
}

还有这个:

ArrayList<Auto> autos = new ArrayList<Auto>();

还有这个:

 public static void loadNewData(ArrayList<Auto> a, ArrayList<Customer> c)
    {
        a.add(new Auto(2009,"Ford" , "Mustang","ABC123", 1256.54));
        a.add(new Auto(2010,"Chevy","Camero","QWI459", 33.98));
        a.add(new Auto(1970,"Pink","Cadillac","950AKH", 212874.51));
        a.add(new Auto(2007,"Lotus","Elise MkII","1A2D3F", 12859.90));

        c.add(new Customer( "Brett Farve",false));
        c.add(new Customer( "Bruce Springsteen",true));
        c.add(new Customer( "Mickey Mouse", true));
        c.add(new Customer( "Peyton Manning", true));
        c.add(new Customer( "Donald Duck", true));
    }

然后我加入所有这些并打印:

System.out.println(autos.toString());

但结果是这样的:

[a 2009 Ford Mustang with a VIN# of ABC123 and a mileage of 1256.54, a 2010 Chevy Camero with a VIN# of QWI459 and a mileage of 33.98, a 1970 Pink Cadillac with a VIN# of 950AKH and a mileage of 212874.51, a 2007 Lotus Elise MkII with a VIN# of 1A2D3F and a mileage of 12859.9]

我怎样才能使打印出来像这样:

  1. 一辆 2009 年福特野马,VIN# 为 ABC123,行驶里程为 1256.54
  2. 2010 Chevy Camero,VIN# 为 QWI459,行驶里程为 33.98
  3. 一辆 1970 年的粉色凯迪拉克,VIN# 为 950AKH,里程为 212874.51
  4. 一辆 2007 年的 Lotus Elise MkII,VIN# 为 1A2D3F,里程为 12859.9

【问题讨论】:

  • 很明显不做System.out.println(autos.toString()); 你不知道如何 A)System.out.print("1. "); 和 B)你不知道如何打印第一个元素的内容吗?你真的应该在头脑中分解问题并询问如何打印第一个元素的内容

标签: java arraylist printing


【解决方案1】:

遍历您的列表并为每个条目执行System.out.println。像这样的:

for (int i = 0; i < autos.size(); i++) {
    System.out.println((i + 1) + ". " + autos.get(i));
}

【讨论】:

    【解决方案2】:

    您可以在退货声明中添加\r \n

    public String toString()
    {
            return "a " + year + " " +  make + " " + model +
                    " with a VIN# of " + vin + " and a mileage of " + miles + "\r \n";
    }
    

    【讨论】:

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