java 数组 去重_java字符串去重的方法「建议收藏」

		//数组去重方法三
		String[] array = {"a","b","c","c","d","e","e","e","a"};
		List<String> list = new ArrayList<>();
		for(int i=0;i<array.length;i++){
			for(int j=i+1;j<array.length;j++){
				if(array[i] == array[j]){
					j = ++i;
				}
			}
			list.add(array[i]);
		}
		String[] arrayResult = (String[]) list.toArray(new String[list.size()]);
		System.out.println(Arrays.toString(arrayResult));

嵌套循环，进行比较获取满足条件结果集。

4、方法四

		//数组去重方法四
		String[] array = {"a","b","c","c","d","e","e","e","a"};
		Arrays.sort(array);
		List<String> list = new ArrayList<>();
		list.add(array[0]);
		for(int i=1;i<array.length;i++){
			if(!array[i].equals(list.get(list.size()-1))){
				list.add(array[i]);
			}
		}
<pre name="code" class="java"><span style="white-space:pre">		</span>String[] arrayResult = (String[]) list.toArray(new String[list.size()]);

5、方法五

//数组去重方法五
		String[] array = {"a","b","c","c","d","e","e","e","a"};
		Set<String> set = new HashSet<>();
		for(int i=0;i<array.length;i++){
			set.add(array[i]);
		}
		String[] arrayResult = (String[]) set.toArray(new String[set.size()]);
		System.out.println(Arrays.toString(arrayResult));

3、知识说明

String[] arrayResult = (String[]) list.toArray(new String[list.size()]);

对应的java方法API

toArray

public Object[] toArray()

Returns an array containing all of the elements in this list in proper sequence (from first to last element).

The returned array will be “safe” in that no references to it are maintained by this list. (In other words, this method must allocate a new array). The caller is thus free to modify the returned array.

This method acts as bridge between array-based and collection-based APIs.

Specified by:

toArray in interface 
Collection<E>

Specified by:

toArray in interface 
List<E>

Overrides:

toArray in class 
AbstractCollection<E>

Returns:

an array containing all of the elements in this list in proper sequence

See Also:

Arrays.asList(Object[])

toArray

public <T> T[] toArray(T[] a)

Returns an array containing all of the elements in this list in proper sequence (from first to last element); the runtime type of the returned array is that of the specified array. If the list fits in the specified array, it is returned therein. Otherwise, a new array is allocated with the runtime type of the specified array and the size of this list.

If the list fits in the specified array with room to spare (i.e., the array has more elements than the list), the element in the array immediately following the end of the collection is set to null. (This is useful in determining the length of the list only if the caller knows that the list does not contain any null elements.)

Specified by:

toArray in interface 
Collection<E>

Specified by:

toArray in interface 
List<E>

Overrides:

toArray in class 
AbstractCollection<E>

Parameters:

a – the array into which the elements of the list are to be stored, if it is big enough; otherwise, a new array of the same runtime type is allocated for this purpose.

Returns:

an array containing the elements of the list

Throws:

ArrayStoreException – if the runtime type of the specified array is not a supertype of the runtime type of every element in this list

NullPointerException – if the specified array is null

2、数组直接打印到控制台

System.out.println(Arrays.toString(arrayResult));