Integer[] a = { 3 , 25 , 12 , 79 , 48 } ;
System.out.println(a);
System.out.println(Arrays.toString(a));
Arrays.sort(a);
System.out.println(Arrays.toString(a));
int idx = Arrays.binarySearch(a, 25 );
System.out.println(idx);
List list = Arrays.asList( 3 , 4 , 5 );
System.out.println(list);
list.set( 2 , 66 );
System.out.println(Arrays.toString(a));
TreeSet ts = new TreeSet();
ts.add( " orange " );
ts.add( " banana " );
ts.add( " apple " );
ts.add( " grape " );
Iterator it = ts.iterator();
while (it.hasNext()) {
String fruit = (String)it.next();
System.out.println(fruit);
HashSet h = new HashSet();
h.add( " 1st " );
h.add( " 2nd " );
h.add( new Integer( 3 ));
h.add( new Double( 4.0 ));
h.add( " 2nd " ); // 重復元素, 未被加入
h.add( new Integer( 3 )); // 重復元素,未被加入
h.add( new Date());
System.out.println( " 開始: size= " + h.size());
Iterator it = h.iterator();
while (it.hasNext()) {
Object o = it.next();
System.out.println(o);
}
h.remove(" 2nd " );
System.out.println( " 移除元素后: size= " + h.size());
System.out.println(h);
ArrayList h = new ArrayList();
h.add( " 1st " );
h.add( " 2nd " );
h.add( new Integer( 3 ));
h.add( new Double( 4.0 ));
h.add( " 2nd " ); // 重復元素, 加入
h.add( new Integer( 3 )); // 重復元素,加入
System.out.println(h);
System.out.println( " size= " + h.size());
System.out.println( " -----替換指定元素----- " );
h.set( 3 , " replace " );
System.out.println( " -----for循環遍歷----- " );
for ( int i = 0 ;i < h.size();i ++ ) {
System.out.println(h.get(i));
}
System.out.println( " -----取用特定元素----- " );
Integer it = (Integer)h.get( 2 );
System.out.println(it.intValue());
System.out.println( " -----插入元素----- " );
h.add( 3 , new Date());
System.out.println( " -----轉換為數組----- " );
Object[] os = h.toArray();
for (Object o : os) {
System.out.println(o);
Vector v = new Vector();
v.add( " 1st " );
v.add( " 2nd " );
v.add( new Integer( 3 ));
v.add( new Double( 4.0 ));
v.add( " 2nd " ); // 重復元素, 加入
v.add( new Integer( 3 )); // 重復元素,加入
System.out.println(v);
System.out.println( " size= " + v.size());
System.out.println( " -----替換指定元素----- " );
v.set( 3 , " replace " );
System.out.println( " -----for循環遍歷----- " );
for ( int i = 0 ;i < v.size();i ++ ) {
System.out.println(v.get(i));
}
System.out.println( " -----取用特定元素----- " );
Integer it = (Integer)v.get( 2 );
System.out.println(it.intValue());
System.out.println( " -----插入元素----- " );
v.add( 3 , new Date());
System.out.println( " -----轉換為數組----- " );
Object[] os = v.toArray();
for (Object o : os) {
System.out.println(o);
Stack s = new Stack();
s.push( " hello " );
s.push( new Date());
s.push( 400 ); // 自動封裝,等價于s.push(new Integer(400));
s.push( 3.14 );
System.out.println( " 彈棧前:size= " + s.size());
System.out.println(s.pop());
System.out.println( " 彈棧后:size= " + s.size());
System.out.println(s.peek());
System.out.println( " peek操作后:size= " + s.size());
while ( ! s.isEmpty())
System.out.println(s.pop());
ArrayList a = new ArrayList();
a.add( " China " );
a.add( " USA " );
a.add( " Korea " );
Iterator it = a.iterator();
while (it.hasNext()) {
String country = (String)it.next();
System.out.println(country);
}
Vector v = new Vector();
v.addElement( new Date());
v.addElement( new Date( 200008755554L ));
it = v.iterator();
while (it.hasNext()) {
Date time = (Date)it.next();
System.out.println(time);
import java.util.Vector;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Enumeration;
public class TestCollections {
public static void main(String[] args) {
ArrayList alist = new ArrayList();
alist.add( 75 );
alist.add( 38 );
alist.add( 21 );
alist.add( 4 );
alist.add( 12 );
System.out.println( " 原列表: " + alist);
Collections.sort(alist);
System.out.println( " 排序后: " + alist);
Collections.reverse(alist);
System.out.println( " 逆序后: " + alist);
Collections.shuffle(alist);
System.out.println( " 混排后: " + alist);
Collections.rotate(alist, 2 );
System.out.println( " 移位后: " + alist);
ArrayList blist = new ArrayList();
blist.add( 55 );
blist.add( 66 );
System.out.println( " 新列表: " + blist);
Collections.copy(alist,blist);
System.out.println( " 拷貝后: " + alist);
System.out.println( " 列表中出現元素66的次數: " + Collections.frequency(alist, 66 ));
System.out.println( " 列表中元素的最大值: " + Collections.max(alist));
System.out.println( " 列表中元素的最小值: " + Collections.min(alist));
Enumeration en = createDemoEnumeration();
ArrayList clist = Collections.list(en);
System.out.println( " Enumeration->ArrayList: " + alist);
}
public static Enumeration createDemoEnumeration() {
Vector v = new Vector();
v.add( " Tom " );
v.add( " Billy " );
v.add( " Jenny " );
return v.elements();
}
}
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