Arrays class

● Arrays Class is used to manipulate the array utility class , It defines the static methods for common array operations .

equals Method

● Compare whether two different arrays are equal , And the array itself equals Judge another number Whether the group itself .

● Statement ：public static boolean equals(type[]a,type[]a2)

● The type of a parameter can be either a native data type or a reference type .

● return ： If two are equal , Then return to true, Otherwise return to false

sort - Sort

● Acts on all elements of the array public static void sort(type[] a)

● Acts on elements in the specified range of the array public static void sort(type[] a, int fromIndex( Include ), int toIndex( barring )) The specified type （ except boolean Any native data type other than ） Array all elements （ Or specified range Elements in the enclosure ） Sort in ascending numerical order . object Type of the array , According to the natural order of the elements , Sorts the array of specified objects in ascending order . （fromIndex==toIndex, The sorting range is empty ）

● Custom object sorting Custom class implementation Comparable Interface rewrite compareTo Method

binarySearch - Use the binary search algorithm to search the specified array

● Statement ： public static int binarySearch(type[] a, type key)

               public static int binarySearch(long[] a,int fromIndex,int toIndex,long key)

● describe ： Use the binary search algorithm to search the specified type Type of the array , To get the specified value .

● Parameters ： a - Array to search .

               key - Value to search .

               fromIndex - Index of the first element to sort （ Include ）.

               toIndex - Index of the last element to sort （ barring ）.

               type -byte、double、float、object、long、int、short、char

● If key In the array , Then return the index of the search value ; Otherwise return to -1 perhaps ”-“ ( The insertion point )

toString() Method

● Statement ：public static String toString(type[] a)

● describe ： Returns a string representation of the contents of a specified array .

● Basic array , The string representation consists of a list of elements of an array , Included in [], Adjacent elements use “ , ”( Comma with space ) Separate .