Java陣列之十大常用方法
摘要：
吶，讓我們先建立一個數組吧。
String[] a = new String[5];
String[] b = {“a”,”b”,”c”, “d”, “e”};
String[] c = new String[]{“a”,”b”,”c”,”d”,”e”};
1.列印陣列
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吶，讓我們先建立一個數組吧。
String[] a = new String[5];
String[] b = {“a”,”b”,”c”, “d”, “e”};
String[] c = new String[]{“a”,”b”,”c”,”d”,”e”};
1.列印陣列
我們經常使用for迴圈或者一些迭代器來打印出陣列的所有元素，但我們也可以換個姿勢。
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.建立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.檢查是否包含某個值
int array[] = {1,2,3,4,5};
boolean isContain= Arrays.asList(array).contains(5);
System.out.println(isContain);
// true
4.連線兩個陣列
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.在一行宣告一個數組
method(new String[]{"a", "b", "c", "d", "e"});
6.陣列倒置
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.刪除某個元素
int[] intArray = { 1, 2, 3, 4, 5 };
int[] removed = ArrayUtils.removeElement(intArray, 3);//create a new array
System.out.println(Arrays.toString(removed));
8.轉化為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.將ArrayList轉化為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.將陣列元素組成一個字串
// Apache common lang
String j = StringUtils.join(new String[] { "a", "b", "c" }, ", ");
System.out.println(j); //a, b, c