Basic use of Java basic----> arrays (i)

Source: Internet
Author: User
Tags concurrentmodificationexception

Arrays are the most efficient way to store and randomly access an object's reference sequence, and we present a simple introduction to arrays today.

Simple use of arrays one, the assignment of arrays
New string[]{"Linux", "Huhx", "Android"}; //  //  array out of string[] Arrays2 = arrays;arrays2[//  Modify the value of Arrays2, Impact on Arrays //  [Linux, Chenhui, Android]arrays[2] = "Google"//  [ Linux, Chenhui, Google]

Second, deep copy of the array
// the bottom implementation is still the System.arrarycopy () method // [Linux, Chenhui, Google] // Modify the value of the ARRAYS3 without affecting the arrays // [Linux, Chenhui, Google]

Three, the padding of the array
New String[4"Linux"//  [Linux , Linux, Linux, Linux]

Iv. Comparison of array contents
boolean arraysequal =//  false//  true

The ordering of the array, changing the array itself
// [Chenhui, Google, Linux]

Vi. searching for elements within an array
int location = Arrays.binarysearch (Arrays, "Linux"//  2

Seven, Array generation ArrayList
list<string> strings = arrays.aslist (Arrays); Iterator<String> Iterator = strings.iterator () ;  while (Iterator.hasnext ()) {    System.out.print ( ());}

Analysis of the Arrays class method

First, fill filling method

 Public Static void Fill (object[] A, Object val) {    for (int i = 0, len = a.length; i < len; i++)        
    = val;}

Two, ToString printing method

 Public StaticString toString (object[] a) {if(A = =NULL)        return"NULL"; intIMax = a.length-1; if(IMax = =-1)        return"[]"; StringBuilder b=NewStringBuilder (); B.append (‘[‘);  for(inti = 0;; i++) {b.append (string.valueof (a[i)); if(i = =IMax)returnB.append ('] '). toString (); B.append (", "); }}

Three, equal comparison method

 Public Static Booleanequals (object[] A, object[] A2) {if(a==A2)return true; if(a==NULL|| a2==NULL)        return false; intLength =a.length; if(A2.length! =length)return false;  for(inti=0; i<length; i++) {Object O1=A[i]; Object O2=A2[i]; if(! (o1==NULL? o2==NULL: O1.equals (O2))) return false; }    return true;}

Iv. ways to convert aslist into lists

@SafeVarargs  Public static <T> list<t> aslist (T ... a) {    returnnew arraylist<> (a);}

Five, iterator traversal method

 PublicIterator<e>iterator () {return NewItr ();}/*** An optimized version of Abstractlist.itr*/Private classItrImplementsIterator<e> {    intCursor//index of next element to return    intLastret =-1;//index of last element returned;-1 if no such    intExpectedmodcount =Modcount;  Public BooleanHasnext () {returnCursor! =size; } @SuppressWarnings ("Unchecked")     PublicE Next () {checkforcomodification ();//check consistency of array contents        inti =cursor; if(I >=size)Throw Newnosuchelementexception (); Object[] Elementdata= ArrayList. This. Elementdata; if(I >=elementdata.length)Throw Newconcurrentmodificationexception (); Cursor= i + 1; return(E) Elementdata[lastret =i]; }     Public voidRemove () {if(Lastret < 0)            Throw Newillegalstateexception ();        Checkforcomodification (); Try{ArrayList. This. Remove (Lastret); Cursor=Lastret; Lastret=-1; Expectedmodcount=Modcount; } Catch(Indexoutofboundsexception ex) {Throw Newconcurrentmodificationexception (); }    }    Final voidcheckforcomodification () {if(Modcount! =expectedmodcount)Throw Newconcurrentmodificationexception (); }}

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Basic use of Java foundation----> Arrays (i)

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