获取数组列表的最后一个值:

var yourlist = ["1","2","3"];
var lastvalue = yourlist[yourlist.length -1];

它给出的输出是3。

我使用micro-util类获取列表的最后(和第一个)元素:

public final class Lists {

    private Lists() {
    }

    public static <T> T getFirst(List<T> list) {
        return list != null && !list.isEmpty() ? list.get(0) : null;
    }

    public static <T> T getLast(List<T> list) {
        return list != null && !list.isEmpty() ? list.get(list.size() - 1) : null;
    }
}

稍微灵活一点:

import java.util.List;

/**
 * Convenience class that provides a clearer API for obtaining list elements.
 */
public final class Lists {

  private Lists() {
  }

  /**
   * Returns the first item in the given list, or null if not found.
   *
   * @param <T> The generic list type.
   * @param list The list that may have a first item.
   *
   * @return null if the list is null or there is no first item.
   */
  public static <T> T getFirst( final List<T> list ) {
    return getFirst( list, null );
  }

  /**
   * Returns the last item in the given list, or null if not found.
   *
   * @param <T> The generic list type.
   * @param list The list that may have a last item.
   *
   * @return null if the list is null or there is no last item.
   */
  public static <T> T getLast( final List<T> list ) {
    return getLast( list, null );
  }

  /**
   * Returns the first item in the given list, or t if not found.
   *
   * @param <T> The generic list type.
   * @param list The list that may have a first item.
   * @param t The default return value.
   *
   * @return null if the list is null or there is no first item.
   */
  public static <T> T getFirst( final List<T> list, final T t ) {
    return isEmpty( list ) ? t : list.get( 0 );
  }

  /**
   * Returns the last item in the given list, or t if not found.
   *
   * @param <T> The generic list type.
   * @param list The list that may have a last item.
   * @param t The default return value.
   *
   * @return null if the list is null or there is no last item.
   */
  public static <T> T getLast( final List<T> list, final T t ) {
    return isEmpty( list ) ? t : list.get( list.size() - 1 );
  }

  /**
   * Returns true if the given list is null or empty.
   *
   * @param <T> The generic list type.
   * @param list The list that has a last item.
   *
   * @return true The list is empty.
   */
  public static <T> boolean isEmpty( final List<T> list ) {
    return list == null || list.isEmpty();
  }
}

列表中的最后一项是list.size() - 1。该集合由一个数组支持，数组从索引0开始。

所以列表中的元素1在数组的下标为0

列表中的元素2位于数组的下标1处

列表中的元素3位于数组的下标2处

等等。

guava提供了另一种从List中获取最后一个元素的方法:

last = Lists.reverse(list).get(0)

如果提供的列表为空，则抛出IndexOutOfBoundsException异常

如果你使用LinkedList代替，你可以通过getFirst()和getLast()访问第一个元素和最后一个元素(如果你想要一个比size() -1和get(0)更干净的方式)

实现

声明一个LinkedList

LinkedList<Object> mLinkedList = new LinkedList<>();

然后这是你可以用来得到你想要的东西的方法，在这种情况下，我们谈论的是列表的FIRST和LAST元素

/**
     * Returns the first element in this list.
     *
     * @return the first element in this list
     * @throws NoSuchElementException if this list is empty
     */
    public E getFirst() {
        final Node<E> f = first;
        if (f == null)
            throw new NoSuchElementException();
        return f.item;
    }

    /**
     * Returns the last element in this list.
     *
     * @return the last element in this list
     * @throws NoSuchElementException if this list is empty
     */
    public E getLast() {
        final Node<E> l = last;
        if (l == null)
            throw new NoSuchElementException();
        return l.item;
    }

    /**
     * Removes and returns the first element from this list.
     *
     * @return the first element from this list
     * @throws NoSuchElementException if this list is empty
     */
    public E removeFirst() {
        final Node<E> f = first;
        if (f == null)
            throw new NoSuchElementException();
        return unlinkFirst(f);
    }

    /**
     * Removes and returns the last element from this list.
     *
     * @return the last element from this list
     * @throws NoSuchElementException if this list is empty
     */
    public E removeLast() {
        final Node<E> l = last;
        if (l == null)
            throw new NoSuchElementException();
        return unlinkLast(l);
    }

    /**
     * Inserts the specified element at the beginning of this list.
     *
     * @param e the element to add
     */
    public void addFirst(E e) {
        linkFirst(e);
    }

    /**
     * Appends the specified element to the end of this list.
     *
     * <p>This method is equivalent to {@link #add}.
     *
     * @param e the element to add
     */
    public void addLast(E e) {
        linkLast(e);
    }

然后你就可以用

mLinkedList.getLast(); 

来获取列表的最后一个元素。

在Java中没有获得列表的最后一个元素的优雅方法(与Python中的items[-1]相比)。

你必须使用list.get(list.size()-1)。

当处理由复杂方法调用获得的列表时，解决方法在于临时变量:

List<E> list = someObject.someMethod(someArgument, anotherObject.anotherMethod());
return list.get(list.size()-1);

这是避免丑陋且昂贵甚至无法工作的版本的唯一选择:

return someObject.someMethod(someArgument, anotherObject.anotherMethod()).get(
    someObject.someMethod(someArgument, anotherObject.anotherMethod()).size() - 1
);

如果能在Java API中引入对这个设计缺陷的修复，那就太好了。