字符串为负的String.Compare()错误 [英] String.Compare() bug with negative number string

问题描述

我测试了string.compare()并得到以下结果.有人可以验证吗?

``-''(破折号/减号)的ascii值为45.
0(零)的ascii值为48.
因此，-"小于任何数字.

每个测试应返回-1，但结果如下:
1. string.Compare(-1"，"2")返回-1
2. string.Compare(-2"，"2")返回1
3. string.Compare(-3"，"2")返回1
4. string.Compare(-1"，"22")返回-1
5. string.Compare(-2"，"22")返回-1
6. string.Compare(-3"，"22")返回1

似乎C#在比较时会忽略-".但是，如果是这样，则测试#2应该返回0.

I tested the string.compare() and got the following results. Can anyone verify it?

''-'' (dash/minus) has an ascii value of 45.
0 (zero) has ascii value of 48.
Therefore, ''-'' is less than any numeral digit.

Each test should return -1, but they comes out as below:
1. string.Compare("-1","2") returns -1
2. string.Compare("-2","2") returns 1
3. string.Compare("-3","2") returns 1
4. string.Compare("-1","22") returns -1
5. string.Compare("-2","22") returns -1
6. string.Compare("-3","22") returns 1

Seem like C# ignores the ''-'' when it compares. However, if that is true, then test #2 should return 0.

推荐答案

String.Compare比较字符串，而不是数字.您看到-2和2返回1的原因是因为该语言试图确定将数字作为单词进行排序的位置.即，如果您尝试执行string.Compare("-a", "a");，将会得到相同的结果.

如果比较数字，则应将其转换为数字.您可以尝试重载Compare方法并将StringComparison.Ordinal用作第三个参数，这应该可以解决问题.

有关MSDN的更多讨论 http://msdn.microsoft.com/zh-cn/library/system.globalization.compareoptions.aspx

戴夫

Hi,

String.Compare compares strings, not numbers. The reason you are seeing the -2 and 2 returning 1 is because the language is trying to determine where the numbers fit in terms of sorting them as words. ie if you tried to do string.Compare("-a", "a"); you will get the same result.

If comparing numbers, they should be converted to numbers. You can try to overload the Compare method and using the StringComparison.Ordinal as a third parameter and that should fix the problem.

There is more discussion on MSDN http://msdn.microsoft.com/en-us/library/system.globalization.compareoptions.aspx

Dave

感谢戴夫，

如果程序员打算比较两个数字，那么他/她将不会使用string.compare().比较两个字符串时，无论字符串内容如何，​​我都希望它们从左到右逐个字符地进行比较.

我很好奇为什么它们同时具有string.Compare()和string.CompareOrdinal().现在，我知道了原因.我喜欢了解string.Compare()行为背后的参数.您提供的链接已断开.你可以看看吗?

本.

Thank Dave,

If a programmer means to compare two numbers, he/she wouldn''t use string.compare(). When compare 2 strings, I would expect they to be compared character by character from left to right regardless of the string contents.

I was curious why they have both string.Compare() and string.CompareOrdinal(). Now, I know the reason. I love to understand the arguments behind string.Compare() behavior. The link you gave is broken. Can you look into that?

Ben.

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