powershell: how to evaluate a string

Question

My file a.txt contains:

delete from test_$suffix

My PowerShell is:

$a = get-content a.txt
$suffix = "tableA"

How would I manipulate $a to obtain the string delete from test_tableA ?

Answer 1

$a=get-content a.txt
$suffix="tableA"

$ExecutionContext.InvokeCommand.ExpandString($a)