这里列举了Java Array 的前十的方法。他们在stackoverflow最大投票的问题。
The following are top 10 methods for Java Array. They are the most voted questions from stackoverflow.
0.声明一个数组
0. Declare an array
String[] aArray = new String[5]; String[] bArray = {"a", "b", "c", "d", "e"}; String[] cArray = {"a", "b", "c", "d", "e"};
1.打印数组
1. Print an array in Java
int[] intArray = {1, 2, 3, 4, 5}; String intArrayString = Arrays.toString(intArray); //直接输出Array，输出,内存地址:[I@4554617c System.out.println(intArray); //输出：[1, 2, 3, 4, 5] System.out.println(intArrayString);
2.从数组中转为ArrayList
2. Create an ArrayList from an array
String[] stringArray = {"a", "b", "c", "d", "e"};
ArrayList<String> arrayList = new ArrayList<>(Arrays.asList(stringArray));
//输出[a, b, c, d, e]
System.out.println(arrayList);
3.判断数组是否含有某值
3. Check if an array contains a certain value
String[] stringArray = {"a", "b", "c", "d", "e"};
boolean b = Arrays.asList(stringArray).contains("a");
//true
System.out.println(b);
4.连接两个数组
4. Concatenate two arrays
//需要导入 org.apache.commons.lang3 int[] intArray1 = {1, 2, 3, 4, 5}; int[] intArray2 = {6, 7 , 8, 9, 10}; int[] combinedIntArray = org.apache.commons.lang3.ArrayUtils.addAll(intArray1, intArray2); String arrayString = Arrays.toString(combinedIntArray); //[1, 2, 3, 4, 5, 6, 7, 8, 9, 10] System.out.println(arrayString);
5.Declare an array inline --- 不知道这个的作用
method(new String[]{"a", "b", "c", "d", "e"});
6.将数组的每个元素取出拼接成字符串
6. Joins the elements of the provided array into a single String
String j = org.apache.commons.lang3.StringUtils.join(new String[] { "a", "b", "c" }, ":");
//a:b:c System.out.println(j);
7.将ArrayList转换为数组
7.Covnert an ArrayList to an array
String[] stringsArray = {"a", "b", "c", "d", "e"};
ArrayList<String> arrayList = new ArrayList<>(Arrays.asList(stringsArray));
String[] stringArr = new String[arrayList.size()];
arrayList.toArray(stringArr);
8.将数组转换为set
8. Convert an array to a set
String[] stringsArray = {"a", "b", "c", "d", "e"};
Set<String> set = new HashSet<String>(Arrays.asList(stringsArray));
System.out.println(set);
9.反转一个数组
9. Reverse an array
String[] stringsArray = {"a", "b", "c", "d", "e"};
ArrayUtils.reverse(stringsArray);
//[e, d, c, b, a]
System.out.println(Arrays.toString(stringsArray));
10.移除数组的某个元素
10. Remove element of an array
int[] intArray = { 1, 2, 3, 4, 5 };
int[] removed = ArrayUtils.removeElement(intArray, 3);//create a new array
System.out.println(Arrays.toString(removed));
One more - convert int to byte array
byte[] bytes = ByteBuffer.allocate(4).putInt(8).array();
for (byte t : bytes) {
System.out.format("0x%x ", t);
}