学习 Class Arrays

技术总结

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Class Arrays

Method Summary

  • asList

返回固定大小List

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List<String> stringList = Arrays.asList("hello", "NTU");

List<Integer> intList = Arrays.asList(1, 2, 3, 4);
  • binarySearch

可以在整个数组中查找，也可以在一定范围内查找

支持Long/int/short/double/char/byte/float/object/T类型数组的查找

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//以int为例

//binarySearch(int[] a, int key)
int index = Arrays.binarySearch(new int[] { 1, 2, 3, 4, 5, 6, 7 }, 6);  

//binarySearch(int[] a, int fromIndex, int toIndex, int key)
int index = Arrays.binarySearch(new int[] { 1, 2, 3, 4, 5, 6, 7 }, 1, 6, 6);
  • copy & copyRange
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String[] names2 = { "Eric", "John", "Alan", "Liz" };  
  
//[Eric, John, Alan]  
String[] copy = Arrays.copyOf(names2, 3);  
          
//[Alan, Liz]  
String[] rangeCopy = Arrays.copyOfRange(names2, 2,  
                names2.length);
  • sort

升序排列

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String[] names = { "Liz", "John", "Eric", "Alan" };  
//只排序前两个  
//[John, Liz, Eric, Alan]  
Arrays.sort(names, 0, 2);  
//全部排序  
//[Alan, Eric, John, Liz]  
Arrays.sort(names);

另外，Arrays的sort方法也可以结合比较器，完成更加复杂的排序。

  • toString

返回数组内容的一个String

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String[] name = {"hahah", "hahah"};
//hahah，hahah
String s = Arrays.toString(name);
  • deepToString

打印多维数组（multidimensional arrays）的内容

  • equls

比较两个一维数组是否相等

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String[] names1 = { "Eric", "John", "Alan", "Liz" };  

String[] names2 = { "Eric", "John", "Alan", "Liz" };  
  
System.out.println(Arrays.equals(names1, names2));
  • deepEquals

判断更复杂的数组是否相等

  • fill

向整个数组或一定范围内的数组填充指定内容