Calling dynamic variable in PowerShell

Solution 1:

First of all, your New-Variable invocation doesn't do what you think it does, as you'd pipe the output of New-Variable to Where-Object instead of using the value of $Transactions | Where ... as value for the variable. You need parentheses for that to work:

New-Variable -Name "Transactions_$Year" -Value ($Transactions | Where {$_.Date -like "*.$Year" })

If you absolutely have to use this approach, then you can get the variables again via Get-Variable:

Get-Variable Transactions_$Year | % Value

However, multiple variables with magic names is a rather poor way of solving this. You probably rather want a map:

$TransactionsPerYear = @{}
$Years | ForEach-Object {
  $TransactionsPerYear[$_] = $Transactions | Where Date -like "*.$_"
}

And you can get all transactions for 2015 with $TransactionsPerYear[2015].

Another way is Group-Object which doesn't even require a list of possible years to begin with, but groups a number of objects by some property or expression result:

$TransactionsPerYear = $Transactions | Group-Object { [int]($_.Date -replace '.*\.') }

(This is a guess on how it could work. It seems like your date string contains something up to a period, after which there is the year and nothing else, so perhaps something like dd.MM.yyyy date format.