java 动态数组列表大小
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Dynamic Array List size
提问by Yuzakii
How can I set size of a dynamic array with Java?
如何使用 Java 设置动态数组的大小?
I tried setsize(...)
with the array variable but not working.
How can I do this?
我尝试setsize(...)
使用数组变量但不起作用。我怎样才能做到这一点?
回答by Jigar Joshi
array size needs to be fixed while initialization, use List
instead and then have array from List
using toArray()
数组大小需要被固定,而初始化,使用List
代替,然后有阵列从List
使用toArray()
For example:
例如:
List<Integer> listOfInt = new ArrayList<Integer>(); //no fixed size mentioned
listOfInt .add(1);
listOfInt .add(2);
listOfInt .add(3);
//now convert it to array
Integer[] arrayOfInt = list.toArray(new Integer[listOfInt .size()]);
回答by tom
Your title is confusing. Are you using an ArrayList or an Array.
An ArrayList
expands and shrinks as needed each time you call the add
, remove
method respectively (or any other add/remove variant). There is no need to manage its size yourself.
你的标题令人困惑。您使用的是 ArrayList 还是 Array。
的ArrayList
膨胀和收缩,因为每个调用所需的时间add
,remove
分别法(或任何其它添加/删除变体)。没有必要自己管理它的大小。
A list is initialized as follows:
一个列表初始化如下:
List<Integer> lst = new ArrayList<Integer>();
Now you have a list where you can add a virtual infinite amount of elements.
现在您有一个列表,您可以在其中添加虚拟无限数量的元素。
An array
needs its size on initialization which cannot be changed without reinitializing.
Anarray
在初始化时需要它的大小,如果不重新初始化就无法更改。