Select Fields From Duplicate Records for an Array - powershell

Question

I've got a CSV file that is imported that looks like this:
Customer ID Contract Start Contract End Region Customer
2-213456 2/20/2018 1/1/2030 NA Acme
2-213456 6/18/2019 6/17/2020 NA Acme
2-213456 6/18/2020 6/30/2021 NA Acme
3-213458 6/27/2019 6/26/2020 CAN Acme Shipping
2-123456 6/27/2020 6/27/2021 AUS Acme Manufacturing
5-123576 6/29/2019 6/28/2020 AUS Acme Storage
Which I'm trying to build an array that only has the unique values (Customer ID) but, would like to include the earliest Contract Start date and the latest Contract End date to get a result like:
Customer ID Contract Start Contract End Region Customer
2-213456 2/20/2018 6/30/2021 NA Acme
3-213458 6/27/2019 6/26/2020 CAN Acme Shipping
2-123456 6/27/2020 6/27/2021 AUS Acme Manufacturing
5-123576 6/29/2019 6/28/2020 AUS Acme Storage
This is what I have but, I keep getting a System.Object[] for the dates
$Data = import-csv -path "C:\Customers.csv"
$Final = #()
$N = 0
$count = $Data.count
foreach ($record in $Data)
{
Write-Host "Record " $N " of " $Count
$Rec = New-Object System.Object
$Rec | Add-Member -type NoteProperty -name "Customer ID" -value $record.'Customer ID'
$StartDate = $Data | Foreach-Object {$_.'Contract Start' = [DateTime]$_.'Contract Start'; $_} | Group-Object 'Customer ID' | Foreach-Object {$_.Group | Sort-Object 'Contract Start' | Select-Object -Property $record.'Contract Start' -first 1}
$Rec | Add-Member -type NoteProperty -name "Contract Start" -value $StartDate
$EndDate = $Data | Foreach-Object {$_.'Contract End' = [DateTime]$_.'Contract End'; $_} | Group-Object 'Customer ID' | Foreach-Object {$_.Group | Sort-Object 'Contract End' | Select-Object -Property $record.'Contract End' -Last 1}
$Rec | Add-Member -type NoteProperty -name "Contract End" -value $EndDate
$Rec | Add-Member -type NoteProperty -name "Region" -value $record.'Region'
$Rec | Add-Member -type NoteProperty -name "Customer" -value $record.'Customer'
$Final += $Rec
$N++
}

Answer 1

I got a lot of errors about Datetime trying to replicate what you have posted above. You've tried to do a lot in one place when setting and sorting the start and end dates, so our first task is to simplify that. Knowing that you could potentially have a lot of customer data, I thought it best to group the customers by their ID in a hashtable. That way we can call the customer ID and immediately just have their records. PowerShell classes allow us to create a couple of methods to import the data in to the hashtable, parse the dates as part of the import. The final method exports your data picking the earliest start date, and the latest end date. Fully tested solution below.
class Customers {
[hashtable]$Accounts
# Constructor
Customers() {
$this.Accounts = #{}
}
# Methods
[void]AddCustomerData([psobject[]]$Records) {
foreach ($Record in $Records) {
# Convert the dates to datetime objects so we can sort them later
$Record = $this.ParseDates($Record)
$ID = $Record."Customer ID"
# If the hashtable already contains the customer ID, we need to add the new record to their existing ones.
if ($this.Accounts.Contains($ID)) {
$CustomerRecords = $this.Accounts[$ID]
$CustomerRecords += $Record
$this.Accounts[$ID] = $CustomerRecords
}
# If it doesn't we create a new record with the value as an array.
else {
$this.Accounts[$ID] = #(,$Record)
}
}
}
[psobject]ParseDates([psobject]$Row) {
# Your dates appear to be US format, so I've kept them that way, change the culture from 'en-US' if you need to.
$Row."Contract Start" = [Datetime]::Parse($Row."Contract Start",[cultureinfo]::new("en-US",$false))
$Row."Contract End" = [Datetime]::Parse($Row."Contract End",[cultureinfo]::new("en-US",$false))
return $Row
}
[psobject[]]PrintCustomerData() {
$CustomerData = #()
# Loop through the hashtable
$this.Accounts.GetEnumerator() | ForEach-Object {
$Contracts = $_.Value
# Find the earliest start date for the current customer by sorting in ascending order
$StartDate = $Contracts."Contract Start" | Sort-Object | Select-Object -First 1
# Find the latest end date for the current customer by sorting in descending order
$EndDate = $Contracts."Contract End" | Sort-Object -Descending | Select-Object -First 1
# Create a new PSObject for each customer, selecting a Unique value for Region and Customer as it should be the same across records
$CustomerData += [PSCustomObject] #{
"Customer ID" = $_.Key
"Contract Start" = $StartDate
"Contract End" = $EndDate
Region = $($Contracts | Select-Object -Unique -ExpandProperty Region)
Customer = $($Contracts | Select-Object -Unique -ExpandProperty Customer)
}
}
return $CustomerData
}
}
Usage:
$csv = Import-Csv -Path .\Desktop\test.csv
# Create a new instance of the class
$customers = [Customers]::new()
# Add the CSV data to a the Accounts hashtable
$customers.AddCustomerData($csv)
# Print out the data from the hashtable in the desired format.
$customers.PrintCustomerData() | Format-Table -AutoSize
Customer ID Contract Start Contract End Region Customer
----------- -------------- ------------ ------ --------
2-213456 20/02/2018 00:00:00 01/01/2030 00:00:00 NA Acme
2-123456 27/06/2020 00:00:00 27/06/2021 00:00:00 AUS Acme Manufacturing
3-213458 27/06/2019 00:00:00 26/06/2020 00:00:00 CAN Acme Shipping
5-123576 29/06/2019 00:00:00 28/06/2020 00:00:00 AUS Acme Storage
And now you have your records in a hashtable, you can do other awesome stuff like look up the records for a particular customer.
$customers.Accounts['2-213456'] | Format-Table -AutoSize
Customer ID Contract Start Contract End Region Customer
----------- -------------- ------------ ------ --------
2-213456 20/02/2018 00:00:00 01/01/2030 00:00:00 NA Acme
2-213456 18/06/2019 00:00:00 17/06/2020 00:00:00 NA Acme
2-213456 18/06/2020 00:00:00 30/06/2021 00:00:00 NA Acme

Answer 2

Using this data.csv as an example input:
Customer ID,Contract Start,Contract End,Region,Customer
2-213456,2/20/2018,1/1/2030,NA,Acme
2-213456,6/18/2019,6/17/2020,NA,Acme
2-213456,6/18/2020,6/30/2021,NA,Acme
3-213458,6/27/2019,6/26/2020,CAN,Acme Shipping
2-123456,6/27/2020,6/27/2021,AUS,Acme Manufacturing
5-123576,6/29/2019,6/28/2020,AUS,Acme Storage
We can use Group-Object to group by Customer ID and use Sort-Object to sort by datetime versions of Contract Start and Contract End. Then we can construct a new System.Management.Automation.PSCustomObject for each compressed record, and format the System.Object[] array with Format-Table.
$array = Import-Csv -Path .\data.csv | Group-Object -Property "Customer ID" | ForEach-Object {
$contractStart = $_.Group |
Sort-Object -Property #{Expression = {[datetime]$_."Contract Start"}} |
Select-Object -First 1
$contractEnd = $_.Group |
Sort-Object -Property #{Expression = {[datetime]$_."Contract End"}} |
Select-Object -Last 1
[PSCustomObject]#{
"Customer ID" = $_.Name
"Contract Start" = $contractStart."Contract Start"
"Contract End" = $contractEnd."Contract End"
"Region" = $contractStart.Region
"Customer" = $contractStart.Customer
}
}
$array.GetType().FullName
$array | Format-Table -AutoSize
Which results in the following table result:
System.Object[]
Customer ID Contract Start Contract End Region Customer
----------- -------------- ------------ ------ --------
2-123456 6/27/2020 6/27/2021 AUS Acme Manufacturing
2-213456 2/20/2018 1/1/2030 NA Acme
3-213458 6/27/2019 6/26/2020 CAN Acme Shipping
5-123576 6/29/2019 6/28/2020 AUS Acme Storage