指数一个ArrayList的ID号 [英] Index the ID number in an ArrayList

问题描述

所以，我有一个从.txt文件取一个ArrayList。它显示以下细节：

So, I have an ArrayList that is taken from a .txt file. It displays the following details:

Id
Car Manufacturer
Car Type
Colour
*blank line*

例如：

21
Vauxhall
Corsa
red

19
Vauxhall
Corsa
blue

18
Vauxhall
Corsa
White

我很好奇，如何使该ID的一个ArrayList的指数，这样，如果汽车被删除或添加到ArrayList，它会自动调整ID号。

I am curious as how to make the Id the "index" of an ArrayList, so that if a car was deleted or added to the Arraylist, It would automatically adjust the Id number.

推荐答案

您使用错误的数据结构...你的目的是这样的HashMap或者LinkedHashMap会更理想。你可以把你所有的汽车数据的POJO

You using wrong DataStructure... For your purpose something like HashMap or LinkedHashMap would be more optimal. You can put all your car data in pojos

class Car {
int Id;
String make, style, color; 
getters/setters....; 
}
List<Car> list = myReadMethod();

//Then you make 
Map<int, Car> myCars = new HashMap<Int, Car>;
for(Car car : list)
     myCars.put(car.getId, car);  

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