== 和 eq 运算符

问题描述

scala> val x = "a"
x: String = a

scala> val y = "a"
y: String = a

据我所知，== 会调用 equals(值相等).

As I understand, == will call equals (value equality).

scala> x == y
res18: Boolean = true

但是，x eq y，出乎我的意料，显示为真.据我了解，eq 检查对象身份.

But, x eq y, unexpected to me, shows true. eq, as I understand, checks for object identity.

scala> x eq y
res19: Boolean = true

Scala 编译器是否足够智能以返回相同的(身份)String 对象?我相信这个词是实习.

Is the Scala compiler smart enough to return the same (identity) String object? I believe the term is interning.

或者，eq 是否真的在执行值相等?

Or, is eq actually performing a value equality?

推荐答案

Scala 的 String 实际上是 Java.Lang.String，实际上使用实习 - 参见 Scala 参考 -

Scala's String is actually Java.Lang.String, which in fact uses interning - see Scala Reference -

type String        = java.lang.String

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