Java数组常用方法
数组基础：http://www.cnblogs.com/mengdd/archive/2013/01/04/2844264.html
import java.util.Arrays;
1):创建数组
1 String[] a = new String[5]; 2 String[] b = {"a","b","c", "d", "e"}; 3 String[] c = new String[]{"a","b","c","d","e"};
2):输出数组
1 import java.util.*; 2 class js 3 { 4 public static void main(String[] args) 5 { 6 int[] a = { 1, 2, 3, 4, 5 }; 7 String b = Arrays.toString(a); 8 9 // print directly will print reference value 10 System.out.println(a); 11 // [I@7150bd4d 12 13 System.out.println(b); 14 // [1, 2, 3, 4, 5] 15 } 16 }
3):从一个数组创建数组列表
1 String[] a = { "a", "b", "c", "d", "e" }; 2 ArrayList<String> List = new ArrayList<String>(Arrays.asList(a)); 3 System.out.println(List); 4 // [a, b, c, d, e]
4):检查一个数组是否包含某个值
1 String[] stringArray = { "a", "b", "c", "d", "e" }; 2 boolean b = Arrays.asList(stringArray).contains("a"); 3 System.out.println(b); 4 // true
5):连接两个数组
1 int[] a = { 1, 2, 3, 4, 5 }; 2 int[] b = { 6, 7, 8, 9, 10 }; 3 int[] c = ArrayUtils.addAll(a,b);
6):声明一个内联数组
1 method(new String[]{"a", "b", "c", "d", "e"});
7):把提供的一个数组放入字符串
1 String j = StringUtils.join(new String[] { "a", "b", "c" }, ", "); 2 System.out.println(j); 3 // a, b, c
8):将一个数组列表转化为数组
1 String[] a = { "a", "b", "c", "d", "e" }; 2 ArrayList<String> aList = new ArrayList<String>(Arrays.asList(a)); 3 String[] b = new String[aList.size()]; 4 aList.toArray(b); 5 for (String s : b) 6 System.out.println(s);
9):将一个数组转化为集(set)
1 Set<String> set = new HashSet<String>(Arrays.asList(stringArray)); 2 System.out.println(set); 3 //[d, e, b, c, a]
10):逆向一个数组
1 int[] intArray = { 1, 2, 3, 4, 5 }; 2 ArrayUtils.reverse(intArray); 3 System.out.println(Arrays.toString(intArray)); 4 //[5, 4, 3, 2, 1]
11):移除数组中的元素
1 int[] intArray = { 1, 2, 3, 4, 5 }; 2 int[] removed = ArrayUtils.removeElement(intArray, 3);//create a new array 3 System.out.println(Arrays.toString(removed));
12):将整数转换为字节数组
1 byte[] bytes = ByteBuffer.allocate(4).putInt(8).array(); 2 for (byte t : bytes) { 3 System.out.format("0x%x ", t); 4 }
