我如何在Scala中表达一个链接的任务？ [英] How would I express a chained assignment in Scala?

问题描述

  a = b = c; 
  

顺便说一下，我重新分配变量（不声明）。

解决方案

Scala中最接近的快捷语法只能在您声明 var 或 val 。

  scala> val c = 1 
 c：Int = 1 
 
 scala> val a，b = c 
a：Int = 1 
b：Int = 1 
  

从Scala Reference，第4.1节

一个值声明val x ₁ ，...，
x _n ：T是值声明val x <1> 的序列
的缩写：T;
...;一个值定义
val p ₁ ，...，p _n = e是一个
的顺序的速度
定义val p ₁ = e; ...; val p _n
= e。值定义val p1 ，...，p _n ：T = e是价值定义val p 1的
序列的简写
：T = e; ...; val p _n ：T = e。

这不适用于重新分配到 VAR 。 C / Java风格不起作用，原因如下： Scala作业评估到单位的动机是什么

How would I express the following java code in scala?

a = b = c;

By the way, I'm re-assigning variables (not declaring).

解决方案

The closest shortcut syntax in Scala can only be used when you declare a var or val.

scala> val c = 1  
c: Int = 1

scala> val a, b = c
a: Int = 1
b: Int = 1

From the Scala Reference, Section 4.1

A value declaration val x₁ , ... , x_n: T is a shorthand for the sequence of value declarations val x₁: T ; ...; val x_n: T. A value definition val p₁, ..., p_n = e is a shorthand for the sequence of value definitions val p₁ = e ; ...; val p_n = e . A value definition val p₁, ... , p_n : T = e is a shorthand for the sequence of value definitions val p₁ : T = e ; ...; val p_n: T = e .

This doesn't work for re-assignement to a var. The C/Java style doesn't work for reasons explained here: What is the Motivation for Scala Assignment Evaluating to Unit

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