Changing Data in Columns in a CSV - powershell

Question

I have a PowerShell script pulling data in from a CSV. What I am trying to do is "replace" the data in the Account column based on the value. For example, Account 001 = Hardware, Account 002 = Software, etc. The data in the CSV is being pulled from a SQL database so if it would be easier for me to change it in the SQL script, I can do that easily. The Account column in the CSV has 001, 002, etc. I want to change those values to Hardware, Software, etc. Thanks for the help.
$Results = import-csv Expenses.csv
$Array = #()
Foreach($R in $Results)
{
$Object = [pscustomobject][ordered] #{
Account = $R.Account
Vendor = $R.Desc1
Item = $R.Desc2
Amount = $R.Amount
}
$Array += $Object
}
$Array

Answer 1

If your CSV looks anything like this:
Account,Vendor,Item,Amount
001,Some Vendor,Something expensive, 1
002,Another Vendor,Something cheapish,26
you can update without a loop:
# create a lookup hashtable where you combine the account values with the wanted replacement
$lookup = #{
'001' = 'Hardware'
'002' = 'Software'
# etcetera
}
# import the csv and update the `Account` column
$Results = Import-Csv D:\Test\Expenses.csv | Select-Object #{Name = 'Account'; Expression = {$lookup[$_.Account]}}, * -ExcludeProperty Account
# display on screen
$Results
# output to (new) csv file
$Results | Export-Csv -Path D:\Test\Expenses_Updated.csv -NoTypeInformation
Result:
Account Vendor Item Amount
------- ------ ---- ------
Hardware Some Vendor Something expensive 1
Software Another Vendor Something cheapish 26
As per the comment of not2qubit some explanation about the Select-Object statement used.
Because the result should reflect all fields in the csv, where the existing field value named Account needs to be replaced, the code uses a Calculated property to set the Account field values using whatever was stored in the lookup Hashtable.
This is done with #{Name = 'Account'; Expression = {$lookup[$_.Account]}}
Next, all other fields contained in the csv are selected unchanged using the asteriks *.
Because we're overwriting the Accound field, but keep its name, the line ends with -ExcludeProperty Account in order to remove the original Account field in the output.
If we don't do that, PowerShell will show an error: Select-Object : The property cannot be processed because the property "Account" already exists.

Answer 2

If I have understood what you require correctly, you just want to change "001" to "Hardware" and so on in the object imported by the Import-Csv cmdlet. You can create a ScriptBlock with a switch that will return a value based off the value you have searched for. I could have recommended a Hashtable here too, but the benefit of a switch over a Hashtable, in this case, is that you can return the value using the default option if it is not specified. For example:
$Lookup = {
Param ([string]$Value)
switch ($Value) {
"001" { "Hardware" }
"002" { "Software" }
default { $Value }
}
}
$Results = Import-Csv Expenses.csv
foreach($R in $Results)
{
# Invoke the scriptblock with the named parameter.
$R.Account = & $Lookup -Value $R.Account
}
# Do stuff with $Results