创建一个数组:
String[] a = new String[5]; String[] b = {“a”,”b”,”c”, “d”, “e”}; String[] c = new String[]{“a”,”b”,”c”,”d”,”e”};
1、打印数组
我们经常使用for循环或者一些迭代器来打印出数组的所有元素,但我们也可以换个姿势。
int array[] = {1,2,3,4,5}; System.out.println(array); //[I@1234be4e String arrStr = Arrays.toString(array); System.out.println(array); //[1,2,3,4,5];
2、创建ArrayList
String[] array = { “a”, “b”, “c”, “d”, “e” }; ArrayList<String> arrayList = new ArrayList<String>(Arrays.asList(array)); System.out.println(arrayList); // [a, b, c, d, e]
3、检查是否包含某个值
int array[] = {1,2,3,4,5}; boolean isContain= Arrays.asList(array).contains(5); System.out.println(isContain); // true
4、连接两个数组
int[] array1 = { 1, 2, 3, 4, 5 }; int[] array2 = { 6, 7, 8, 9, 10 }; // Apache Commons Lang library int[] combinedIntArray = ArrayUtils.addAll(array1, array2);
5、在一行声明一个数组
method(new String[]{"a", "b", "c", "d", "e"});
6、数组倒置
int[] intArray = { 1, 2, 3, 4, 5 }; // Apache Commons Lang library ArrayUtils.reverse(intArray); System.out.println(Arrays.toString(intArray)); //[5, 4, 3, 2, 1]
7、删除某个元素
int[] intArray = { 1, 2, 3, 4, 5 }; int[] removed = ArrayUtils.removeElement(intArray, 3);//create a new array System.out.println(Arrays.toString(removed));
8、转化为set
Set<String> set = new HashSet<String>(Arrays.asList(new String[]{"a", "b", "c", "d", "e"})); System.out.println(set); //[d, e, b, c, a]
9、将Array List转化为Array
String[] stringArray = { "a", "b", "c", "d", "e" }; ArrayList<String> arrayList = new ArrayList<String>(Arrays.asList(stringArray)); String[] stringArr = new String[arrayList.size()]; arrayList.toArray(stringArr);
10、将数组元素组成一个字符串
// Apache common lang String j = StringUtils.join(new String[] { "a", "b", "c" }, ", "); System.out.println(j); //a, b, c
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