Loading two arrays from a CSV

Question

I have a CSV File that has two columns Employee and Manager and I would like to import them into two Variables for use later in my script. However when I run my code it only captures the last data item in the CSV as the previous one is being over written.

$CSVFiles = Import-CSV "C:\T2\EmployeeManager.csv"

ForEach($CSVFile in $CSVFiles)
{
  $Employee = ($CSVFile.Employee); $Manager = ($CSVFile.Manager)
}

Answer 1

$Employee = $CSVFiles | Select -Expand Employee
$Manager  = $CSVFiles | Select -Expand Manager

Answer 2

That's because you are overwriting the added data each time the loop runs. IN PowerShell the += appends to an object. Try this -

$Employee = @()
$Manager = @()

$CSVFiles = Import-CSV "C:\T2\EmployeeManager.csv"

ForEach($CSVFile in $CSVFiles)
{
  $Employee += $CSVFile.Employee; $Manager += $CSVFile.Manager
}

Answer 3

Vivek Kumar Singh's helpful answer explains the problem with your approach well and offers a solution.

Here's a simpler alternative (PSv3+), given that you're loading the entire CSV file into (custom objects) into memory anyway:

$CSV = Import-CSV "C:\T2\Employee.csv"

$Employees = $CSV.Employee  # collect the Employee column values across all input rows
$Managers  = $CSV.Manager   # ditto for Manager

This approach takes advantage of the PSv3+ member-access enumeration feature.

In PSv2, use iRon's helpful solution.

---

Comparing the performance of the solutions:

• The member-enumeration solution in this answer is fastest,
• followed by iRon's Select -Expand solution
• with Vivek's foreach loop being the slowest by far, not least because use of += to (conceptually) extend an array requires creating a new instance behind the scenes in every iteration.

Answer 4

This ended up being my final coding to accomplish my end goal. I want to thank all the posters I used a little learning from all of you to come to the solution I wanted.

$EmployeeLists = @()
$ManagerLists = @()
$Employees = @()
$Managers = @()


$CSVFiles = Import-CSV "C:\T2\EmployeeManager.csv"

ForEach($CSVFile in $CSVFiles)
{
  $EmployeeLists += ($CSVFile.Employee)
}

ForEach($CSVFile in $CSVFiles)
{
  $ManagerLists += ($CSVFile.Manager)
}

$Employees += ForEach ($EmployeeList in $EmployeeLists) { Get-ADUser -Properties * -Filter { DisplayName -like $EmployeeList } | Select SamAccountName -ExpandProperty SamAccountName }
$Managers += ForEach ($ManagerList in $ManagerLists) { Get-ADUser -Properties * -Filter { DisplayName -like $ManagerList } | Select SamAccountName -ExpandProperty SamAccountName }


$EmployeeLists
"`n`n`n"
$Employees