12 best methods for Java arrays, and 12 methods for java Arrays

12 best methods for Java arrays, and 12 methods for java Arrays

 

1. Declare an array

 

    String[] aArray = new String[5];      String[] bArray = {"a","b","c", "d", "e"};      String[] cArray = new String[]{"a","b","c","d","e"};  

 

 

2. Output an array

 

    int[] intArray = { 1, 2, 3, 4, 5 };      String intArrayString = Arrays.toString(intArray);             // print directly will print reference value      System.out.println(intArray);      // [I@7150bd4d             System.out.println(intArrayString);      // [1, 2, 3, 4, 5]  

 

3. Create an array list 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]  

 

4. Check whether an array contains a value.

 

    String[] stringArray = { "a", "b", "c", "d", "e" };      boolean b = Arrays.asList(stringArray).contains("a");      System.out.println(b);      // true  

 

 

5. connect two Arrays

 

    int[] intArray = { 1, 2, 3, 4, 5 };      int[] intArray2 = { 6, 7, 8, 9, 10 };      // Apache Commons Lang library      int[] combinedIntArray = ArrayUtils.addAll(intArray, intArray2);  

 

 

6. Declare an inline Array (Array inline)

 

method(new String[]{"a", "b", "c", "d", "e"}); 

 

7. Put the provided array element into a string

 

    // containing the provided list of elements      // Apache common lang      String j = StringUtils.join(new String[] { "a", "b", "c" }, ", ");      System.out.println(j);      // a, b, c  

 

8. convert an array list 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);

 

9. convert an array to a set)

Set<String> set = new HashSet<String>(Arrays.asList(stringArray));  System.out.println(set);  //[d, e, b, c, a]

 

10. Reverse an array

 

    int[] intArray = { 1, 2, 3, 4, 5 };      ArrayUtils.reverse(intArray);      System.out.println(Arrays.toString(intArray));      //[5, 4, 3, 2, 1]  

 

11. Remove elements from the array

 

    int[] intArray = { 1, 2, 3, 4, 5 };      int[] removed = ArrayUtils.removeElement(intArray, 3);//create a new array      System.out.println(Arrays.toString(removed));  

 

12. Convert integers into byte Arrays

 

    byte[] bytes = ByteBuffer.allocate(4).putInt(8).array();             for (byte t : bytes) {         System.out.format("0x%x ", t);      }