Scala 克隆后仍修改原始数组的元素

我有以下代码：

val copyA = a.clone
copyA(0)(0) = 1
println("a(0)(0): " + a(0)(0))

这张照片是：

a(0)(0): 1

如果我将其更改为：

val copyA = a.clone
println("a(0)(0): " + a(0)(0))

它打印：

a(0)(0): 0

那么为什么

a

会受到

copyA

中的更改的影响呢

---

如何使

copyA

中的更改不影响

a

？

您克隆了阵列。你没有克隆阵列中的任何东西

---

在代码中，您没有操作数组。您将从数组中获取一个元素并操作该对象。这里的数组完全不相关。

您克隆了数组。你没有克隆阵列中的任何东西

---

在代码中，您没有操作数组。您将从数组中获取一个元素并操作该对象。这里的数组完全不相关。

变异克隆的1D数组实例不会改变原始实例，反之亦然

例如

scala> val original = Array(100, 200)
original: Array[Int] = Array(100, 200)

scala> val cloned = original.clone
cloned: Array[Int] = Array(100, 200)

变异

克隆

数组不会影响

原始

数组，

scala> cloned(0) = 5000

scala> original(0) //still the same value
res36: Int = 100

scala> original(0) = 8888

scala> cloned(0) // still the same
res38: Int = 5000

scala> val original = Array.ofDim[Int](2,2)
original: Array[Array[Int]] = Array(Array(0, 0), Array(0, 0))

scala> original.foreach {col => println(col)}
[I@745e24c4
[I@42c6563f

变异

原始

数组不会影响

克隆

数组，

scala> cloned(0) = 5000

scala> original(0) //still the same value
res36: Int = 100

scala> original(0) = 8888

scala> cloned(0) // still the same
res38: Int = 5000

scala> val original = Array.ofDim[Int](2,2)
original: Array[Array[Int]] = Array(Array(0, 0), Array(0, 0))

scala> original.foreach {col => println(col)}
[I@745e24c4
[I@42c6563f

但是对于2D数组它是不同的，因为里面的每个数组都是一个ref，必须进行深度克隆

scala> cloned(0) = 5000

scala> original(0) //still the same value
res36: Int = 100

scala> original(0) = 8888

scala> cloned(0) // still the same
res38: Int = 5000

scala> val original = Array.ofDim[Int](2,2)
original: Array[Array[Int]] = Array(Array(0, 0), Array(0, 0))

scala> original.foreach {col => println(col)}
[I@745e24c4
[I@42c6563f

深度克隆2D阵列

scala> val cloned = original.map(_.clone)
cloned: Array[Array[Int]] = Array(Array(0, 0), Array(0, 0))

scala> original(0)(0) = 5000

scala> cloned(0)(0)
res43: Int = 0

//changing cloned does not change original array 
scala> cloned(0)(0) = 8888

scala> original(0)(0)
res48: Int = 5000

---

变异克隆的1D数组实例不会改变原始实例，反之亦然

例如

scala> val original = Array(100, 200)
original: Array[Int] = Array(100, 200)

scala> val cloned = original.clone
cloned: Array[Int] = Array(100, 200)

变异

克隆

数组不会影响

原始

数组，

scala> cloned(0) = 5000

scala> original(0) //still the same value
res36: Int = 100

scala> original(0) = 8888

scala> cloned(0) // still the same
res38: Int = 5000

scala> val original = Array.ofDim[Int](2,2)
original: Array[Array[Int]] = Array(Array(0, 0), Array(0, 0))

scala> original.foreach {col => println(col)}
[I@745e24c4
[I@42c6563f

变异

原始

数组不会影响

克隆

数组，

scala> cloned(0) = 5000

scala> original(0) //still the same value
res36: Int = 100

scala> original(0) = 8888

scala> cloned(0) // still the same
res38: Int = 5000

scala> val original = Array.ofDim[Int](2,2)
original: Array[Array[Int]] = Array(Array(0, 0), Array(0, 0))

scala> original.foreach {col => println(col)}
[I@745e24c4
[I@42c6563f

但是对于2D数组它是不同的，因为里面的每个数组都是一个ref，必须进行深度克隆

scala> cloned(0) = 5000

scala> original(0) //still the same value
res36: Int = 100

scala> original(0) = 8888

scala> cloned(0) // still the same
res38: Int = 5000

scala> val original = Array.ofDim[Int](2,2)
original: Array[Array[Int]] = Array(Array(0, 0), Array(0, 0))

scala> original.foreach {col => println(col)}
[I@745e24c4
[I@42c6563f

深度克隆2D阵列

scala> val cloned = original.map(_.clone)
cloned: Array[Array[Int]] = Array(Array(0, 0), Array(0, 0))

scala> original(0)(0) = 5000

scala> cloned(0)(0)
res43: Int = 0

//changing cloned does not change original array 
scala> cloned(0)(0) = 8888

scala> original(0)(0)
res48: Int = 5000

---

您的两个案例都是相同的

copyA（0）（0）=1

，这就是您的意思吗？您的两个代码段都是相同的对不起，我更新了它。您的两个案例都可能重复

copyA（0）（0）=1

，这就是您的意思吗？您的两个代码段都是相同的对不起，我更新了它可能重复的