为变量分配下划线.下划线在做什么? [英] Assign a underscore to a variable. What is the underscore doing?

问题描述

最近我遇到了这样的代码:

Recently I've run into code like this:

var myVariable: variableKind = _

这似乎是一种将 null 分配给 myVariable 的方法.

It seems to be a way to assign null to myVariable.

谁能解释一下这种情况下 _ 背后的原理?将 _ 和 null 分配给变量有什么区别?

Can anyone explain the rationale behind _ in this case? What are the differences between assigning _ and null to a variable?

推荐答案

它用它的默认值初始化变量 - 这个值取决于类型.对于数字类型，这是 zero，false 是布尔值，() 是 Unit 和 null 扩展 <代码>AnyRef.

It initialises the variable with it's default value - this value depends on the type. For numeric types, this is zero, false for booleans, () for Unit and null for types extending AnyRef.

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