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] |
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