Powershell 格式差异

我有两段代码：

$allUsers = Get-ADUser -Filter *
foreach($_ in $allUsers.Name){
    Write-Host "User $_ is member of the following groups:" -for Yellow
    Get-ADPrincipalGroupMembership -Identity $_ | select Name,objectClass,Groupscope,Groupcategory | sort Name | Format-Table
}
User Administrator is member of the following groups:

Name                 objectClass                  Groupscope       Groupcategory
----                 -----------                  ----------       -------------
Administrators       group                       DomainLocal            Security
Distributed COM U... group                       DomainLocal            Security
Domain Admins        group                            Global            Security
Domain Users         group                            Global            Security
Enterprise Admins    group                         Universal            Security
Group Policy Crea... group                            Global            Security
HelpLibraryUpdaters  group                       DomainLocal            Security
Schema Admins        group                         Universal            Security


User Guest is member of the following groups:

Name                 objectClass                  Groupscope       Groupcategory
----                 -----------                  ----------       -------------
Domain Guests        group                            Global            Security
Guests               group                       DomainLocal            Security

另一个版本如下所示：

    $allUsers = Get-ADUser -Filter *
    foreach($_ in $allUsers.Name){
        Write-Host "User $_ is member of the following groups:"
        Get-ADPrincipalGroupMembership -Identity $_ | select Name,objectClass,Groupscope,Groupcategory | sort Name
    }

User Administrator is member of the following groups:

Name                 objectClass                  Groupscope       Groupcategory
----                 -----------                  ----------       -------------
Administrators       group                       DomainLocal            Security
Distributed COM U... group                       DomainLocal            Security
Domain Admins        group                            Global            Security
Domain Users         group                            Global            Security
Enterprise Admins    group                         Universal            Security
Group Policy Crea... group                            Global            Security
HelpLibraryUpdaters  group                       DomainLocal            Security
Schema Admins        group                         Universal            Security
User Guest is member of the following groups:
Domain Guests        group                            Global            Security
Guests               group                       DomainLocal            Security

---

在我看来，后者更容易阅读。我的问题是这是；为什么第一段代码显示每个用户的标题？在我看来，select对象是为$allUsers.Name中的每个用户调用的，因此每次都应该在后者中显示标题？

区别在于调用

格式表的次数。在第一个示例中，为每个用户调用它。这意味着为每个用户打印标题。在第二个示例中，仅调用一次
格式表
，因此标题仅打印一次

第二个命令末尾有一个隐含的
格式表
，因此如果执行此操作：

$allUsers = Get-ADUser -Filter *
foreach($_ in $allUsers.Name){
    Write-Host "User $_ is member of the following groups:"
    Get-ADPrincipalGroupMembership -Identity $_ | select Name,objectClass,Groupscope,Groupcategory | sort Name
} | Format-Table 

你应该得到同样的结果
 不知道格式表是隐含的。谢谢