在交互式 Scala 控制台中打印整个结果 [英] Print whole result in interactive Scala console

问题描述

当我在 Scala 交互式控制台中输入内容时，控制台会打印语句的结果.如果结果太长，控制台将其裁剪(向右滚动查看):

When I type something into the Scala interactive console, the console prints the result of the statement. If the result is too long, the console crops it (scroll right to see it):

scala> Array.fill[Byte](5)(0)
res1: Array[Byte] = Array(0, 0, 0, 0, 0)

scala> Array.fill[Byte](500)(0)
res2: Array[Byte] = Array(0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, ...

scala> "a"*5000
res3: String = aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa...

如何在不发生裁剪的情况下为任何给定对象(不仅仅是集合或数组)打印相同或等效的输出?

How can I print the same or equivalent output, for any given object (not just a collection or array) without the cropping occurring?

推荐答案

结果不是裁剪"的，只是 println 调用了 java.lang.Arrays.toString()code>(因为 scala.Array 是一个 Java 数组).

The result is not "cropped", simply println is invoking java.lang.Arrays.toString() (since scala.Array is a Java array).

具体来说，Arrays 定义了一个与 Object 一起工作的 toString 重载，它调用了 toString 的实现.code>java.lang.Object 在每个元素上.这样的实现打印了对象的引用，所以你最终得到

Specifically, Arrays defines a toString overload that works with Object, which calls the toString implementation of java.lang.Object on every element. Such implementation prints the reference of the object, so you end up with

[Lscala.Tuple2;@4de71ca9

这是一个 Array，包含对 scala.Tuple2 对象的引用 4de71ca9.

which is an Array containing the reference 4de71ca9 to a scala.Tuple2 object.

多年前这张票中已经讨论过这一点.

That has been discussed in this ticket years ago.

在数组的特定情况下，你可以简单地做

In the specific case of arrays, you can simply do

println(x.mkString("\n"))

或

x foreach println

或

println(x.deep)

<小时>

更新

要回答您上次的编辑，您可以设置 REPL 打印的字符串的最大长度

---

Update

To answer your last edit, you can set the maximum lenght of the strings printed by the REPL

scala> :power
** Power User mode enabled - BEEP WHIR GYVE **
** :phase has been set to 'typer'.          **
** scala.tools.nsc._ has been imported      **
** global._, definitions._ also imported    **
** Try  :help, :vals, power.<tab>           **

scala> vals.isettings.maxPrintString = Int.MaxValue
vals.isettings.maxPrintString: Int = 2147483647

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