数组 --------集合中的各种遍历方法!!!!!--binbinyang

(包名用了中文,大家不要在意这个)

1.数组

    1.for

2.增强for

package 杨彬_数组;public class ArrayDemo {/* * 数组遍历的方式: 1.for 2.增强for */public static void main(String[] args) {int[] arr = { 1, 2, 3, 4, 5 };test1();test2(arr);}//增强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.for

2.增强for

3.迭代器

4.toArray

package 杨彬_Collection;import java.util.ArrayList;import java.util.Collection;import java.util.Iterator;/* * 遍历方式  :  1. for(不写了)  2,增强for  3.迭代器 4.toArray */public class CollectionDemo {public static void main(String[] args) {Collection<String> c = new ArrayList<String>() ;c.add("杨彬");c.add("郭乐乐");c.add("科比");c.add("乔丹");//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]);}}//迭代器private static void test2(Collection<String> c) {Iterator<String>  it = c.iterator(); while(it.hasNext()){System.out.println(it.next());}}//增强FORprivate static void test1(Collection<String> c) {for(String c1 : c){System.out.println(c1);}}}

3.List

package 数组_List;import java.util.ArrayList;import java.util.Iterator;import java.util.List;import java.util.ListIterator;/* * for * 增强for * 迭代器 * list特有迭代器 * 角标get() * toArray() */public class ListDemo {public static void main(String[] args) {List<String> c = new ArrayList<String>() ;c.add("杨彬");c.add("郭乐乐");c.add("科比");c.add("乔丹");//test1(c);//test2(c);//test3(c);//test4(c);test5(c); test6(c);}private static void test6(List<String> c) {for(ListIterator<String> lit = c.listIterator(); lit.hasNext();){System.out.println(lit.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]);}}//角标get();private static void test4(List<String> c) {for(int i=0;i<c.size();i++){System.out.println(c.get(i));}}//LIst迭代器private static void test3(List<String> c) {ListIterator<String> lsc = c.listIterator();while(lsc.hasNext()){System.out.println(lsc.next());}}//迭代器private static void test2(List<String> c) {Iterator<String> it = c.iterator();while(it.hasNext()){System.out.println(it.next());}}//增强forprivate static void test1(List<String> c) {for(String c1: c){System.out.println(c1);}}}

3.Set

package 杨彬_Set;import java.util.HashSet;import java.util.Iterator;import java.util.Set;/* * 迭代器 * 增强for * toArray *  */public class SetList {public static void main(String[] args) {Set<String> c = new HashSet<String>() ;c.add("杨彬");c.add("郭乐乐");c.add("科比");c.add("乔丹");//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]);}}//增强forprivate static void test2(Set<String> c) {for(String s:c){System.out.println(s);}}//迭代器private static void test1(Set<String> c) {Iterator<String> it = c.iterator();while(it.hasNext()){System.out.println(it.next());}}}

4.Map

package 杨彬_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,"杨彬");c.put(2,"郭乐乐");c.put(3,"科比");c.put(4,"乔丹");//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 只能取值 private static void test1(Map<Integer, String> c) {Collection<String> co = c.values();for(String s : co){System.out.println(s);}}}