在交互式 Scala 控制台中打印整个结果

Print whole result in interactive Scala console

提问by Sampo

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):

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，控制台会裁剪它（向右滚动查看）：

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...

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

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？

回答by Gabriele Petronella

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

结果不是“裁剪”，只是println调用java.lang.Arrays.toString()（因为scala.Array是 Java 数组）。

Specifically, Arraysdefines a toStringoverload that works with Object, which calls the toStringimplementation of java.lang.Objecton every element. Such implementation prints the reference of the object, so you end up with

具体来说，Arrays定义了一个toString与 一起使用的重载Object，它在每个元素上调用 的toString实现java.lang.Object。这样的实现打印对象的引用，所以你最终

[Lscala.Tuple2;@4de71ca9

which is an Arraycontaining the reference 4de71ca9to a scala.Tuple2object.

这是一个Array包含参考4de71ca9到一个scala.Tuple2对象。

That has been discussed in this ticketyears ago.

多年前在这张票中已经讨论过这一点。

---

---

In the specific case of arrays, you can simply do

在数组的特定情况下，您可以简单地执行

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

or

或者

x foreach println

or

或者

println(x.deep)

---

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Update

更新

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

要回答您的上次编辑，您可以设置 REPL 打印的字符串的最大长度

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

回答by Pengfei.X

try this

试试这个

scala> :power
Power mode enabled. :phase is at typer.
import scala.tools.nsc._, intp.global._, definitions._
Try :help or completions for vals._ and power._

scala> vals.isettings.maxPrintString
res9: Int = 800

scala> vals.isettings.maxPrintString = 10000
vals.isettings.maxPrintString: Int = 10000

回答by Govind Singh

try

尝试

x map println

or

或者

x foreach println