Scala 单位类型 [英] Scala Unit type

问题描述

我用opencsv解析csv文件，我的代码是

I use opencsv to parse csv files, and my code is

while( (line = reader.readNext()) != null ) { .... }

我收到一个编译器警告说:

I got a compiler warning saying:

 comparing values of types Unit and Null using `!=' will always yield true
 [warn]     while( (aLine = reader.readNext()) != null ) {

我应该怎么做while循环?

How should I do the while loop?

推荐答案

在你的例子中 (line = reader.readNext()) 是一个返回类型 Unit 的函数式文字.您可以按如下方式重写代码:

In your case (line = reader.readNext()) is a functional literal that returns type Unit. You may rewrite the code as follows:

while( {line = reader.readNext();  line!= null} ) { .... }

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