list,set,map,陣列間的相互轉換

1.list轉set 

set set =  new  hashset( new  arraylist());     

set set = new hashset(new arraylist());

list list =  new  arraylist( new  hashset());     

list list = new arraylist(new hashset());

list stooges = arrays.aslist( "larry" ,  "moe" ,  "curly" );     

list stooges = arrays.aslist("larry", "moe", "curly"); 
此時stooges中有有三個元素。

int a = ;  

set set = new hashset(arrays.aslist(a)); 
set set = new hashset(arrays.aslist(a));

map map =  new  hashmap();       

map.put( "1" , "a" ); 
map.put( '2' , 'b' ); 
map.put( '3' , 'c' ); 
system.out.println(map); 
// 輸出所有的值 
system.out.println(map.keyset()); 
// 輸出所有的鍵 
system.out.println(map.values()); 
// 將map的值轉化為list 
list list = new arraylist(map.values()); 
system.out.println(list); 
// 將map的值轉化為set 
set set = new hashset(map.values()); 
system.out.println(set);

list list = arrays.aslist( "a" , "b" );       

system.out.println(list); 
string arr = (string)list.toarray( new string[list.size()]); 
system.out.println(arrays.tostring(arr));

list,set,map,陣列間的相互轉換

list,set,map,陣列間的相互轉換 1.list轉set set set new hashset new arraylist 2.set轉list list list new arraylist new hashset 3.陣列轉為list list stooges arrays.aslis...

list,set,map,陣列間的相互轉換

list,set,map,陣列間的相互轉換 1.list轉set set set new hashset new arraylist 2.set轉list list list new arraylist new hashset 3.陣列轉為list list stooges arrays.aslis...

List Set Map 之間的區別

1.可重複。2.可以為空。3.有序容器，保持了每個元素的插入順序，輸出的順序就是插入的順序。常用的實現類有 arraylist linkedlist 和 vector。arraylist 最為流行，它提供了使用索引的隨意訪問，而 linkedlist 則對於經常需要從 list 中新增或刪除元素的場...