对象数组与自定义标头的比较 [英] Object Array Comparison with Custom Headers

问题描述

我有一个从两个中心提取的角色对象数组.

I have an object array of roles I pulled from two vcenters.

我正在尝试制作一个有 3 列的格式化表:角色、主、从

I'm trying to make a formatted table that has 3 columns : roles, master, slave

后两列会有exists"或missing".

There would be "exists" or "missing" in the latter two columns.

我认为发生的问题是，当它发现该角色存在于 master 中时，它会以某种方式将 slave 列标记为缺失"，即使我知道它在那里.

The problem I believe happening is when it finds that the role exists in the master, it somehow marks the slave column as "missing", even though I know it's there.

我才刚接触 Powershell 几个月，有人能看出我的逻辑有什么问题吗?

I'm only a few months into Powershell, can anyone see anything wrong with my logic?

RoleTable.AllRoles、RoleTable.MasterRoles 和 RoleTable.SlaveRoles 都是对象数组

edit: RoleTable.AllRoles, RoleTable.MasterRoles, and RoleTable.SlaveRoles are all object arrays

    $RoleTable.AllRoles | Select-Object Name, 
    @{Name = "Master Server"; Expression = {if ($RoleTable.MasterRoles -contains $_) {"EXISTS"} else {"MISSING"}}}, 
    @{Name = "Slave Server"; Expression = {if ($RoleTable.SlaveRoles -contains $_) {"EXISTS"} else {"MISSING"}}}

Roletable.Allroles 对象示例:

Example of Roletable.Allroles object:

$RoleTable.AllRoles[1] | Select-Object *


Description   : Not logged-in user (cannot be granted)
IsSystem      : True
PrivilegeList : {System.Anonymous}
ServerId      : /VIServer=someuser@xxxx-xxxx:443/
Server        : 
Id            : -4
Name          : Anonymous
Uid           : /VIServer=someuser@xxxx-xxxx:Role=-4/
ExtensionData : VMware.Vim.AuthorizationRole
Client        : VMware.VimAutomation.ViCore.Impl.V1.VimClient

推荐答案

除非 $RoleTable.AllRoles[1] 和 $RoleTable.SlaveRoles 中的项目参考 内存中完全相同的对象，-contains 将返回 $false，即使 看似em> $RoleTable.SlaveRoles 中存在相同的对象.

Unless $RoleTable.AllRoles[1] and an item in $RoleTable.SlaveRoles refer to the exact same object in memory, -contains will return $false, even if a seemingly identical object exists in $RoleTable.SlaveRoles.

(这仅适用于引用类型，而不适用于值类型)

(this is only true for reference types, not value types)

这应该说明区别:

对同一对象的引用:

PS C:\> $Collection = @(New-Object psobject -Property @{p=123})
PS C:\> $Item       = $Collection[0]
PS C:\> $Collection -contains $Item 
True 

对相同对象的引用:

PS C:\> $Collection = @(New-Object psobject -Property @{p=123})
PS C:\> $Item       = New-Object psobject -Property @{p=123}
PS C:\> $Collection -contains $Item 
False

在您的示例中，您可以使用 Name 或角色 Id 属性(如@jisaak 所建议):

In your example, you could use the Name or role Id property (as suggested by @jisaak):

$RoleTable.AllRoles | Select-Object Name, 
@{Name = "OnMaster"; Expression = {$RoleTable.MasterRoles.Id -contains $_.Id}}, 
@{Name = "OnSlave"; Expression = {$RoleTable.SlaveRoles.Id -contains $_.Id}}

如上所示，我可能会使用通用布尔值作为指标，而不是字符串

As shown above, I would probably use generic boolean values as indicators, rather than strings

这种行为是 .NET 中的一种刻意的性能优化 - 您永远不知道要确保对对象的所有内部属性进行精确的值比较，您需要深入到兔子洞的深处.

This behaviour is a deliberate performance optimization in .NET - you never know how deep down the rabbit hole you would need to go to ensure exact value comparison of all internal attributes of an object.

另一方面，值类型更容易执行相等比较(并且也不一定有要比较的内存引用)，结果:

Value types, on the other hand, are easier to perform equality comparisons against (and also don't necessarily have a memory reference to compare), resulting in:

[int]

PS C:\> $Collection = @(283)
PS C:\> $Item       = $Collection[0]
PS C:\> $Collection -contains $Item
True
PS C:\> $Item       = 283
PS C:\> $Collection -contains $Item
True

[string]:

PS C:\> $Collection = @("SomeString")
PS C:\> $Item       = $Collection[0]
PS C:\> $Collection -contains $Item
True
PS C:\> $Item       = "SomeString"
PS C:\> $Collection -contains $Item
True

等等...

这篇关于对象数组与自定义标头的比较的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！