使用==还是equals的字符串比较 [英] Using == or Equals for string comparison

问题描述

在某些语言（如C ++），你不能使用类似==操作符进行字符串比较，将比较字符串对象的地址，而不是字符串本身。然而，在C＃中，你可以使用==来比较字符串，它实际上将比较字符串的内容。但也有字符串函数来处理这样的比较，所以我的问题是;你应该？

In some languages (e.g. C++) you can't use operators like == for string comparisons as that would compare the address of the string object, and not the string itself. However, in C# you can use == to compare strings, and it will actually compare the content of the strings. But there are also string functions to handle such comparisons, so my question is; should you?

由于两个字符串：

string aa = "aa"; 
string bb = "bb";

如果您对它们进行比较是这样的：

Should you compare them like this:

bool areEqual = (aa == bb); 

还是应该用平等的功能，像这样的：

Or should you use the Equal function, like this:

bool areEqual = aa.Equals(bb); 

有什么技术区别呢？最佳做法还是合理的论据？

Is there any technical difference anyway? Or reasonable arguments for best practice?

推荐答案

我不会用：

aa.Equals(bb)

除非我知道 AA 不可能的可能的为空。我可能是：

unless I knew aa couldn't possibly be null. I might use:

string.Equals(aa,bb)

但是我主要使用它，我想用特定的一个 StringComparison 模式（不变，顺序，不区分大小写，等等）。虽然我也可以使用 StringComparer 的实现，因为它们更容易一点抽象的（例如，通过成词典＆LT;字符串，富＆GT; 为不区分大小写的有序字典）。对于通用的用法，

But I'd mainly use that it I wanted to use one of the specific StringComparison modes (invariant, ordinal, case-insensitive, etc). Although I might also use the StringComparer implementations, since they are a bit easier to abstract (for example, to pass into a Dictionary<string, Foo> for a case-insensitive ordinal dictionary). For general purpose usage,

a == b

是好的。

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