二元运算符“<=”的错误操作数类型

Question

I can't seem to figure out why I'm getting this error. I've tried putting everything in parenthesis and that helped the problem a little bit. It would be great if I could get some help.

Code :

public void merge(String[] result, String[] nameA, String[] nameB)
{
    int i1 = 0;   // index into nameA array
    int i2 = 0;   // index into nameB array

    for (int i = 0; i < result.length; i++) 
    {
        if (i2 >= nameB.length || (i1 < nameA.length && nameA[i1] <= nameB[i2])) 
        {
            result[i] = nameA[i1];    // take from nameA
            i1++;
        } 
        else 
        {
            result[i] = nameB[i2];   // take from nameB
            i2++;
        }
    }
}

error: bad operand types for binary operator '<='

Answer 1

In order to compare String s in Java you need to call the method compareTo . Have a look at the Comparable interface that String implements.

Answer 2

<= and >= operators are for numeric primitive types like int or double . To compare String s, use compareTo method.

nameA[i1].compareTo(nameB[i2]) < 0

If you want to compare String s by length, then use <= operator on String#length instead:

nameA[i1].length() <= nameB[i2].length()

Answer 3

除了 Luiggi Mendoza 和 Ivaylo Strandjev 的答案之外，我想指出的是，如果您只想确保字符串不同，您可以像这样使用 equals：

if (i2 >= nameB.length || (i1 < nameA.length && !nameA[i1].equals(nameB[i2])))