Quick example of saving results to arrays when implicit output was getting complicated

Result Summaries using Arrays and Export-Excel.ps1

using namespace System.Collections.Generic

# Say you want one table that has all results, with fixed columns
[list[Object]]$Summary      = @()

# and a second array that's just errors with extra info
[list[Object]]$ErrorSummary = @()

foreach( $user in $UserCsv ) {  
    $result =  [pscustomobject]@{
        FirstLast      = $Name
        EmployeeNumber = $Number
        Result         = 'Ok'
    }
    try { 
        #  maybe throws ...         
        $Summary.Add( $Result )             
    }
    catch { 
        # write the error to the error stream and save 
        Write-Error "User Iter failed: $_"

        $result.Result = $_.Exception.Message
        $Summary.Add( $Result )

        $ErrorSummary.Add(
            [pscustomobject]@{
                ExceptionObject = $_
                FirstLast       = $Name
                EmployeeNumber  = $Number
                When            = (Get-Date).ToString('o')
            }
        )
    } 
}

$exportExcelSplat = @{
    Title         = 'All Results'
    TableName     = 'SummaryData'
    WorksheetName = 'Summary'
    TableStyle    = 'Light2'
    Path          = 'c:\foo\out.xlsx'
}
$Summary | Export-Excel @exportExcelSplat

$exportExcelSplat = @{
    Title         = 'Error Context'
    TableName     = 'Errors'
    WorksheetName = 'ErrorInfo'
    TableStyle    = 'Light2'
    Path          = 'c:\foo\out.xlsx'
}
$ErrorSummary | Export-Excel @exportExcelSplat

To Use Strict Column Names.ps1

# If you really want to ensure you have fixed columns for your summary
# then check out classes. You can use them sort of like a  "record struct"
# Compared to [PSCO] which allow arbitrary and unbalanced names

[List[SummaryRecord]] $SummaryRecords = @()

class SummaryRecord {
    [string] $FirstLast
    [int] $EmployeeNumber
    [string] $Result
}

# Classes let you use the hashtable contructor syntax

$SummaryRecords.Add( 
    [SummaryRecord]@{    
        FirstLast      = 'bob'
        EmployeeNumber = 123
        Result         = 'Success'
    }
)