Array.binarySearch返回负数 [英] Array.binarySearch returning negative numbers

问题描述

我正在尝试使用Arrays.binarySearch（）方法在字符串数组中查找字符串的索引，但是当查找字符串 Free时，该方法似乎返回位置整数 -5。知道为什么会这样吗？

I am trying to find the index of a string in a string array using the Arrays.binarySearch() method however the method seems to be return the postion integer "-5" when looking for the string "Free". Any idea why this would be?

String[] names = {"Arken","Ben","Darklark", "Free","group"};

void changeFriends(String uname, boolean b)
        {   // change a friend's "online" status

    Arrays.sort(names);
    int index = Arrays.binarySearch(names, uname);

    System.out.println("NAME OF ONLINE USER IS AT INDEX:" + index + "Name:" + uname);
        if(index > -1)
        {

             if(b == true)
            {
                loggedOn[index] = true;
            }
            else
            {
                loggedOn[index] = false;
            }
        }
        // call method to update buttons
        changeNameButtons();
    }

推荐答案

嗯，我只是跑了代码，我得到了索引3。

Hmm, i just ran your code and i got the index 3.

Arrays.sort(names);
int index = Arrays.binarySearch(names, "Free");
System.out.println(index);

您可能正在搜索免费或免费（带有空格），而不是免费，在这种情况下，它返回-5。

you probably are searching free or Free(with a trailing white space) instead of Free, in which case it returns -5.

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