开关表达式不能是浮点型、双精度型或布尔型

switch expression can#39;t be float, double or boolean(开关表达式不能是浮点型、双精度型或布尔型)

问题描述

为什么 switch 表达式不允许 long、float、double 或 boolean Java 中的值?为什么只允许int(以及那些自动提升为int的)?

Why doesn't the switch expression allow long, float, double or boolean values in Java? why is only int (and those that are automatoically promoted to int) allowed?

推荐答案

即使可能，Float 和 double 也很难可靠地使用 - 不要忘记在 float/double 上执行完全相等匹配通常是个坏主意无论如何，由于表示的性质.

Float and double would be awkward to use reliably even if they were possible - don't forget that performing exact equality matches on float/double is usually a bad idea anyway, due to the nature of the representation.

对于布尔值，为什么不直接使用 if 开头?

For Boolean values, why not just use if to start with?

老实说，我不记得曾经想要打开这些类型中的任何一种.您有特定的用例吗?

I can't remember ever wanting to switch on any of these types, to be honest. Do you have a particular use case in mind?

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