深度复制阵列 [英] Deep-copy an array

问题描述

我一直在把头撞在墙上.
我知道，如果我在Powershell中创建一个数组，然后复制该数组，它将把它复制为引用类型而不是值类型.
因此，经典示例是:

I've been banging my head against the wall on this one.
I know that if I create an Array in Powershell, then copy the array, it'll copy it as a reference type not a value type.
So, the classic example is:

$c = (0,0,0)
$d = $c
$c[0] = 1
$d
1
0
0

解决方案是执行$d = $c.clone() 如果数组本身是引用类型的集合，则此方法不起作用.这是我的问题.我正在尝试通过创建一个进程数组来创建一个数组来跟踪CPU使用率，请稍等片刻，然后检查最新值并计算差异.但是，Get-Process会创建一个引用数组.因此，当我执行以下操作时:

The solution is to do $d = $c.clone() This isn't working though if the array itself is a collection of reference types. This is my problem. I'm trying to create an array to track CPU usage by creating an array of Processes, wait a while, then check the latest values and calculate the differences. However the Get-Process creates a reference array. So when I do the following:

$a = ps | sort -desc id | where-object {$_.CPU -gt 20} #Get current values
$b = $a.clone() #Create a copy of those values.
sleep 20 #Wait a few seconds for general CPU usage...

$a = ps | sort -desc id | where-object {$_.CPU -gt 20} #Get latest values.
$a[0]  
$b[0] #returns the same value as A.

Handles  NPM(K)    PM(K)      WS(K) VM(M)   CPU(s)     Id ProcessNam
-------  ------    -----      ----- -----   ------     -- ----------
   3195      57    90336     100136   600    83.71   7244 OUTLOOK

$a和$b将始终返回相同的值.如果我尝试使用$ b [0] ="$ a [0] .clone()"来一次输入一个条目-PS抱怨在这种情况下不能使用Clone.

$a and $b will always return the same value. If I try and do it one entry at a time using something like $b[0] = "$a[0].clone()" - PS complains that Clone can't be used in this case.

有什么建议吗?

此外，仅供参考，由于$a是PS列表对象的引用类型，因此实际上并不需要第二条$a = PS |....行，只要调用$a，它实际上就会更新并返回最新的值.我包括了它，以使我在这里想要完成的工作更清楚.

Also, just FYI, the second $a = PS |.... line isn't actually needed since $a is reference type to the PS list object, it actually gets updated and returns the most current values whenever $a is called. I included it to make it clearer what I'm trying to accomplish here.

推荐答案

要复制数组，可以执行以下操作:

To copy an array, you can do the following:

$c = (0,0,0)
$d = $c | foreach { $_ }
$c[0] = 1
"c is [$c]"
"d is [$d]"

结果

c is [1 0 0]
d is [0 0 0]

对于您的特定问题(比较进程的CPU使用率)，正如Keith指出的那样，更具体一些可能会更好.

For your particular issue (comparing CPU usage of processes), something more specific would probably be better, as Keith pointed out.

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