是 if-let 还是正常的 if 条件更好? [英] Is an if-let or a normal if condition better?

问题描述

例如:

fn foo() -> Option<()> {
     // ...
}

fn bar() -> Option<()> {
    if let None = foo() { // <---- here
        return None;
    }
}

然后我将 if 语句改为:

Then I changed the if-statement to:

if None == foo()

它也有效.

可以用 a == b 代替 if let a = b 吗?

Is it ok to use a == b instead of if let a = b?

推荐答案

回应和扩展 Magnus Hoff 的观点，当我关心匹配的值时，我只使用 if let .在这个例子中，我会使用类似 Option::is_none 进一步强调我不在乎:

Echoing and expanding on Magnus Hoff's point, I only use if let when I care about the value being matched against. In this example, I'd use something like Option::is_none to further highlight that I don't care:

if foo().is_none() { 

这有一个微小的好处，即回避包装 T 以实现 PartialEq 的要求，如 fjh 指出.

This has the tiny benefit of sidestepping the requirement for the wrapped T to implement PartialEq, as fjh points out.

然而，根据我的经验，这种特殊结构很少见，因为通常你想在 Some 情况下做一些事情.一旦你有多个分支，我就会升级到 match 语句.

In my experience however, this particular construct is rarely seen because usually you want to do something in the Some case. Once you have multiple branches, I upgrade to a match statement.

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