Author: X Wang
Source: http://www.programcreek.com/2013/09/top-10-methods-for-java-arrays/
Repost the article. repost the article with the author and source.
The following are top 10 methods for Java Array. They are the most voted questions from stackoverflow.
0. Declare an array
String[] aArray = new String[5];String[] bArray = {"a","b","c", "d", "e"};String[] cArray = new String[]{"a","b","c","d","e"}; |
1. Print an array in Java
int[] intArray = { 1, 2, 3, 4, 5 };String intArrayString = Arrays.toString(intArray); // print directly will print reference valueSystem.out.println(intArray);// [I@7150bd4d System.out.println(intArrayString);// [1, 2, 3, 4, 5] |
2. Create an ArrayList from an array
String[] stringArray = { "a", "b", "c", "d", "e" };ArrayList<String> arrayList = new ArrayList<String>(Arrays.asList(stringArray));System.out.println(arrayList);// [a, b, c, d, e] |
3. Check if an array contains a certain value
String[] stringArray = { "a", "b", "c", "d", "e" };boolean b = Arrays.asList(stringArray).contains("a");System.out.println(b);// true |
4. Concatenate two arrays
int[] intArray = { 1, 2, 3, 4, 5 };int[] intArray2 = { 6, 7, 8, 9, 10 };// Apache Commons Lang libraryint[] combinedIntArray = ArrayUtils.addAll(intArray, intArray2); |
5. Declare an array inline
method(new String[]{"a", "b", "c", "d", "e"}); |
6. Joins the elements of the provided array into a single String
// containing the provided list of elements// Apache common langString j = StringUtils.join(new String[] { "a", "b", "c" }, ", ");System.out.println(j);// a, b, c |
7. Covnert an ArrayList to an 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);for (String s : stringArr)System.out.println(s); |
8. Convert an array to a set
Set<String> set = new HashSet<String>(Arrays.asList(stringArray));System.out.println(set);//[d, e, b, c, a] |
9. Reverse an array
int[] intArray = { 1, 2, 3, 4, 5 };ArrayUtils.reverse(intArray);System.out.println(Arrays.toString(intArray));//[5, 4, 3, 2, 1] |
10. Remove element of an array
int[] intArray = { 1, 2, 3, 4, 5 };int[] removed = ArrayUtils.removeElement(intArray, 3);//create a new arraySystem.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);} |