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java中Arrays的用法
阅读量:469 次
发布时间:2019-03-06

本文共 1119 字,大约阅读时间需要 3 分钟。

1. atList方法:返回一个固定大小的list

Modifier and Type Method and Description
static <T> <T> (T... a)
Returns a fixed-size list backed by the specified array.

应用:

1  List
intList = Arrays.asList(1, 2, 3, 4);

2. binarySearch方法 :折半查找法 ,返回所给元素的索引

static int (int[] a, int fromIndex, int toIndex, int key)
Searches a range of the specified array of ints for the specified value using the binary search algorithm

应用:

1 //fromIndex,toIndex这两个参数可以省略(表示整个数组) 2 //不省略表示在这个区间查找,左闭右开, key 表示要查找的元素 3 //返回要查找元素的 索引位置 4 int index = Arrays.binarySearch(new int[] { 1, 2, 3, 4, 5, 6, 7 }, 3); 5 public static int binarySearch(byte[] a, int fromIndex, int toIndex, byte key)

 

3. copyOf及copyOfRange方法 :将一个数组拷贝到另一个数组中/或者其中的一部分

 

1 int[] a ={1,2,3,4,5};2 int[] b =Arrays.copyOf(a, 2);            //1 2 3 4 int[] c = Arrays.copyOfRange(a, 0, 3);        //左闭合右开  1 2 3

4. sort方法:排序 (升序)

1 int[] a ={7,2,5,4,3};2 Arrays.sort(a);                            //2 3 4 5 7

Arrays.sort(a, fromIndex, toIndex);     可以指定数组排序的开始和结束的位置 (左闭右合)

 

5. equals方法:比较两个数组

1 int[] a ={7,2,5,4,3};2 int[] b = {1,2,3}3 System.out.println(a.equals(b));          //false

 

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