The basic operation method of Java array sorting _java

An array is a set of data that has the same data type. Java supports multiple arrays, each base cell of a one-dimensional array is data of the basic data type, and the two-dimensional array is a one-dimensional array of one-dimensional arrays, and so on, each basic unit of an n-dimensional array is an array of n-1 dimensions that are n-1 arrays. The following is an example of a one-dimensional array to illustrate the use of Java arrays.

1. Array declaration

The array declaration has the following two forms (the square brackets differ in position):

int arr[];
Int[] ARR2;

2, array initialization

There are also two forms of array initialization, as follows (using new or not using new):

int arr[] = new Int[]{1, 3, 5, 7, 9};
Int[] arr2 = {2, 4, 6, 8, 10};

3, traversing the array

The traversal array can be For/foreach, as follows:

  public static void Main (string[] args) {
    int arr[] = new Int[]{1, 3, 5, 7, 9};
    Int[] arr2 = {2, 4, 6, 8, ten};
    for (int i = 0; i < arr.length ++i) {
      System.out.print (Arr[i] + "T");//1 3 5 7 9
    } for
    (int x:arr2) {
      System.out.print (x + "T");//2 4 6 8
    }
  }

4, Arrays.fill () Fill array

Using the static method of the Arrays class, import package java.util.Arrays is required, and many overloaded methods are defined.

void Fill (int[] A, int val) all fills 
void Fill (int[] A, int fromindex, int toindex, int val) fills the element of the specified index

    int[] Arr3 = new INT[5];
    for (int x:arr3) {
      System.out.print (x + "T");//0 0 0 0 0 all initialized to 0
    }
    System.out.println ();
    Arrays.fill (ARR3);
    for (int x:arr3) {
      System.out.print (x + "T");//10 10 10 10 10 all filled with the
    System.out.println ();
    Arrays.fill (ARR3, 1, 3, 8);
    for (int x:arr3) {
      System.out.print (x + "T");//10 8 8 10 10 populate the specified index
    }
    System.out.println ();

5, Arrays.sort () array sorting

void sort (int[] a) all sort 
void sort (int[] A, int fromindex, int toindex) Sorts the elements of the specified index

    int[] Arr4 = {3, 7, 2, 1, 9};
    Arrays.sort (ARR4);
    for (int x:arr4) {
      System.out.print (x + "T");//1 2 3 7 9
    }
    System.out.println ();
    Int[] Arr5 = {3, 7, 2, 1, 9};
    Arrays.sort (ARR5, 1, 3);
    for (int x:arr5) {
      System.out.print (x + "T");//3 2 7 1 9
    }
    System.out.println ();

6, arrays.copyof () copy array

Int[] copyof (int[] original, int newlength) copies the array, specifying the new array length 
int[] Copyofrange (int[] original, int from, int to) copies the array, Specifies the index of the original array being copied

    int[] arr6 = {1, 2, 3, 4, 5};
    int[] arr7 = arrays.copyof (ARR6, 5); 1 2 3 4 5
    int[] arr8 = Arrays.copyofrange (ARR6, 1, 3);//2 3 for
    (int x:arr7) {
      System.out.print (x + "T" );
    }
    System.out.println ();
    for (int x:arr8) {
      System.out.print (x + "T");
    }
    System.out.println ();

7, check whether the array contains a value

String[] Stringarray = {"A", "B", "C", "D", "E"};
Boolean B = Arrays.aslist (Stringarray). Contains ("a");
System.out.println (b);
True

Use Arrays.aslist () to convert an array to List<string>, so that you can use the contains function of a dynamic list to determine whether an element is contained in a list.

8. Connect two arrays

Int[] Intarray = {1, 2, 3, 4, 5};
Int[] IntArray2 = {6, 7, 8, 9, ten};
Apache Commons Lang Library
int[] Combinedintarray = Arrayutils.addall (Intarray, intArray2);

Arrayutils is an array processing class library provided by Apache, and its AddAll method makes it easy to connect two arrays into an array.

9. Array Flip

Int[] Intarray = {1, 2, 3, 4, 5};
Arrayutils.reverse (intarray);
System.out.println (arrays.tostring (Intarray));
[5, 4, 3, 2, 1]

Still use the omnipotent arrayutils.

10. Remove an element 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));