Question

我有三个列表，即list1，list2，list3我的代码在获取以下列表输出时工作正常： O / P

Getting the list1 objects  [man, animal, jackel]
Getting the list2 objects  [1, 2, 3]
Getting the list3 objects  [bobby, lion, dilip]

现在我想把list4作为[man,1,bobby] 并将list5列为[man,1,bobby , animal,2,lion , jackel,3,dilip]

这是我的代码，它给出了list1，list2，list3

的输出

List<String> list1 = new ArrayList<String>();  
List<String> list2 = new ArrayList<String>();  
List<String> list3 = new ArrayList<String>();  

String splitstring="man,animal,jackel";
String splitid="1,2,3";
String splitscreenname="bobby,lion,dilip";

String[] arrsplitstring=splitstring.split(",");
String[] arrssplitid=splitid.split(",");
String[] arrsplitedscreenname=splitscreenname.split(",");

List<String> wordList = Arrays.asList(arrsplitstring);
List<String> wordid = Arrays.asList(arrssplitid);
List<String> wordscreenlist = Arrays.asList(arrsplitedscreenname);

for (int i=0;i<wordList.size();i++){
    list1.add(wordList.get(i));
}
System.out.println("Getting the list1 objects  " +list1 );

for(int i=0;i<wordid.size();i++){
    list2.add(wordid.get(i));
}
System.out.println("Getting the list2 objects  " +list2);

for (int i=0;i<wordscreenlist.size();i++){      
    list3.add(wordscreenlist.get(i));
}
System.out.println("Getting the list3 objects  " +list3);

我通过迭代每个列表对象来尝试它，但我几乎找不到解决方案。

提前致谢

Answer 1

您要做的是迭代其中一个List并将所有3个Lists中的项目添加到新List。

您可能想要实际做的是拥有一个Animal对象，包含来自3个原始List的属性。

这是一个例子（注意：这里是Java 7语法）：

// initializing lists
List<String> animals = new ArrayList<>(
    Arrays.asList(new String[]{"man", "animal", "jackal"})
);
List<Number> numbers = new ArrayList<>(
    Arrays.asList(new Number[]{1, 2, 3})
);
List<String> names = new ArrayList<>(
    Arrays.asList(new String[]{"bobby", "lion", "dilip"})
);

// sequential list of objects
List<Object> allObjects = new ArrayList<>();

// class describing an "animal", wrapping the 3 properties
class Animal {
    String type;
    Number number;
    String name;
    Animal(String type, Number number, String name) {
        this.type = type;
        this.number = number;
        this.name = name;
    }
    // fancy String representation
    @Override
    public String toString() {
        return String.format("Type: %s, Number: %d, Name: %s%n", type, number, name);
    }
}

// list of Animals
List<Animal> allAnimals = new ArrayList<>();

// iterating the first list (arbitrary choice)
for (int i = 0; i < animals.size(); i++) {

    // adding sequentially to objects list
    allObjects.add(animals.get(i));
    // TODO check for index out of bounds
    allObjects.add(numbers.get(i));
    allObjects.add(names.get(i));

    // adding to animals list sequentially with 3 props each animal
    allAnimals.add(new Animal(animals.get(i), numbers.get(i), names.get(i)));
}

// printing out values
System.out.println("All objects...");
System.out.println(allObjects);

System.out.println("All animals...");
System.out.println(allAnimals);

<强>输出

All objects...
[man, 1, bobby, animal, 2, lion, jackal, 3, dilip]
All animals...
[Type: man, Number: 1, Name: bobby
, Type: animal, Number: 2, Name: lion
, Type: jackal, Number: 3, Name: dilip
]

Answer 2

第一个可能是这样的：

List<String> list4 = new ArrayList<String>();

// Check the three lists have the same number of elements.
// If not, return (you have to show and error)    
if (! (
  (wordListIt.size() == wordidIt.size() ) 
  && 
  (wordidIt.size() == wordscreenlistIt.size() )
) ) return;

Iterator<String> wordListIt = wordList.iterator();
Iterator<String> wordidIt = wordid.iterator();
Iterator<String> wordscreenlistIt = wordscreenlist.iterator();
while (wordListIt.hasNext()) {
        list4.add(wordListIt.next());
        list4.add(wordidIt.next());
        list4.add(wordscreenlistIt.next());
        break; // exit the while, because you only want the first element.
}

第二个可能是这样的：

List<String> list5 = new ArrayList<String>();

// Check the three lists have the same number of elements.
// If not, return (you have to show and error)    
if (! (
  (wordListIt.size() == wordidIt.size() ) 
  && 
  (wordidIt.size() == wordscreenlistIt.size() )
) ) return;

Iterator<String> wordListIt = wordList.iterator();
Iterator<String> wordidIt = wordid.iterator();
Iterator<String> wordscreenlistIt = wordscreenlist.iterator();
while (wordListIt.hasNext()) {
        list5.add(wordListIt.next());
        list5.add(wordidIt.next());
        list5.add(wordscreenlistIt.next());
}

Answer 3

您需要遍历每个列表的元素以获得所需的结果。

List<String> list4 = new ArrayList<String>(); 
list4.add(list1.get(0)); 
list4.add(list2.get(0)); 
list4.add(list3.get(0)); 

List<String> list5 = new ArrayList<String>();
for(int ctr=0;ctr<list3.size();ctr++)
{
   list5.add(list1.get(ctr)); 
   list5.add(list2.get(ctr)); 
   list5.add(list3.get(ctr));
}

如何通过在java中迭代3个不同的列表对象来向列表对象添加元素？

3 个答案: