Array, java Array

Array, java Array

(The package name uses Chinese characters. Do not care about this)

1. Array

1.

2. Enhanced

Package Yang bin_array; public class ArrayDemo {/** array Traversal method: 1.for 2. enhance for */public static void main (String [] args) {int [] arr = {1, 2, 3, 4, 5}; test1 (); test2 (arr);} // enhance forprivate static void test2 (int [] arr) {for (int I: arr) {System. out. println (I) ;}// forprivate static void test1 () {int [] arr = {1, 2, 3, 4, 5}; for (int I = 0; I <arr. length; I ++) {System. out. println (arr [I]) ;}}

2. Collection

1.

2. Enhanced

3. iterator

4. toArray

Package Yang Bin _ Collection; import java. util. arrayList; import java. util. collection; import java. util. iterator;/** traversal mode: 1. for (NO) 2, enhanced for 3. iterator 4. toArray */public class CollectionDemo {public static void main (String [] args) {Collection <String> c = new ArrayList <String> (); c. add ("Yang Bin"); c. add ("guo Lele"); c. add ("Kobe"); c. add ("Jordan"); // test1 (c); // test2 (c); test3 (c);} // toArrayprivate static void test3 (Collection <String> c) {Object [] cc = c. toArray (); for (int I = 0; I <cc. length; I ++) {System. out. println (cc [I]) ;}// Iterator private static void test2 (Collection <String> c) {Iterator <String> it = c. iterator (); while (it. hasNext () {System. out. println (it. next () ;}// enhance FORprivate static void test1 (Collection <String> c) {for (String c1: c) {System. out. println (c1 );}}}

3. List

Package array _ List; import java. util. arrayList; import java. util. iterator; import java. util. list; import java. util. listIterator;/** for * enhancement for * iterator * list-specific iterator * badge get () * toArray () */public class ListDemo {public static void main (String [] args) {List <String> c = new ArrayList <String> (); c. add ("Yang Bin"); c. add ("guo Lele"); c. add ("Kobe"); c. add ("Jordan"); // test1 (c); // test2 (c); // test3 (c); // test4 (c); test5 (c ); test6 (c);} private static void test6 (List <String> c) {for (ListIterator <String> operator = c. listIterator (); iterator. hasNext ();) {System. out. println (bytes. next () ;}// toArray () private static void test5 (List <String> c) {Object [] array = c. toArray (); for (int I = 0; I <array. length; I ++) {System. out. println (array [I]) ;}// badge get (); private static void test4 (List <String> c) {for (int I = 0; I <c. size (); I ++) {System. out. println (c. get (I) ;}}// LIst iterator private static void test3 (List <String> c) {ListIterator <String> lsc = c. listIterator (); while (lsc. hasNext () {System. out. println (lsc. next () ;}// Iterator private static void test2 (List <String> c) {Iterator <String> it = c. iterator (); while (it. hasNext () {System. out. println (it. next () ;}// enhance forprivate static void test1 (List <String> c) {for (String c1: c) {System. out. println (c1 );}}}

3. Set

Package Yang Bin _ Set; import java. util. hashSet; import java. util. iterator; import java. util. set;/** iterator * enhancement for * toArray **/public class SetList {public static void main (String [] args) {Set <String> c = new HashSet <String> (); c. add ("Yang Bin"); c. add ("guo Lele"); c. add ("Kobe"); c. add ("Jordan"); // test2 (c); // test1 (c); test3 (c);} // toArray () private static void test3 (Set <String> c) {Object [] array = c. toArray (); for (int I = 0; I <array. length; I ++) {System. out. println (array [I]) ;}// enhance forprivate static void test2 (Set <String> c) {for (String s: c) {System. out. println (s) ;}}// Iterator private static void test1 (Set <String> c) {Iterator <String> it = c. iterator (); while (it. hasNext () {System. out. println (it. next ());}}}

4. Map

Package Yang Bin _ Map; import java. util. collection; import java. util. hashMap; import java. util. map; import java. util. set; import java. util. map. entry;/* VAlues * keyset * entryset */public class MapDemo {public static void main (String [] args) {Map <Integer, String> c = new HashMap <Integer, string> (); c. put (1, "Yang Bin"); c. put (2, "Guo Lele"); c. put (3, "Kobe"); c. put (4, "Jordan"); // test1 (c); // test2 (c); test3 (c);} private static void test3 (Map <Integer, string> c) {for (Entry <Integer, String> entry: c. entrySet () {System. out. println (entry. getKey () + ":" + entry. getValue () ;}// keysetprivate static void test2 (Map <Integer, String> c) {Set <Integer> set = c. keySet (); for (Integer key: set) {String value1 = c. get (key); System. out. println (key + ":" + value1) ;}// Values can only be set to private static void test1 (Map <Integer, String> c) {Collection <String> co = c. values (); for (String s: co) {System. out. println (s );}}}