明确地与布尔常量进行比较是否不好，例如如果 (b == false) 在 Java 中? [英] Is it bad to explicitly compare against boolean constants e.g. if (b == false) in Java?

问题描述

写的不好:

if (b == false) //...

while (b != true) //...

是否总是改为写:

if (!b) //...

while (!b) //...

大概在性能上没有区别(或者有没有?)，但是你如何权衡两者之间的明确性、简洁性、清晰性、可读性等?

Presumably there is no difference in performance (or is there?), but how do you weigh the explicitness, the conciseness, the clarity, the readability, etc between the two?

为了限制主观性，我也很感激权威编码风格指南中的任何引用，关于哪种总是更可取或何时使用.

To limit the subjectivity, I'd also appreciate any quotes from authoritative coding style guidelines over which is always preferable or which to use when.

注意:变量名b只是举例，ala foo and bar.

Note: the variable name b is just used as an example, ala foo and bar.

推荐答案

这不一定是坏事，它只是多余的.此外，实际变量名称的权重很大.例如，我更喜欢 if (userIsAllowedToLogin) 高于 if (b) 或更糟糕的 if (flag).

It's not necessarily bad, it's just superfluous. Also, the actual variable name weights a lot. I would prefer for example if (userIsAllowedToLogin) above if (b) or even worse if (flag).

至于性能问题，编译器会以任何方式对其进行优化.

As to the performance concern, the compiler optimizes it away at any way.

更新:至于权威来源，我在 Sun 编码约定，但至少 Checkstyle 有 SimplifyBooleanExpression 模块会对此发出警告.

Update: as to the authoritative sources, I can't find something explicitly in the Sun Coding Conventions, but at least Checkstyle has a SimplifyBooleanExpression module which would warn about that.

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