I’m working with Plaster and in doing so, have a few hash tables in my workspace. Suddenly, and out of nowhere, I had a thought: Can I put a Read-Host command, as the value of a key-value pair inside of a hash table? Yes, but before we get too far into this, here’s a simple hash table example without any Read-Host commands.

$Params = @{
    meal = 'lunch'
    food = 'Ramen'
    drink = 'Tea'
}
$Params

Name                           Value
----                           -----
drink                          Tea
food                           Ramen
meal                           lunch

Okay, that was simple: Choose a variable name, prefix it with a dollar sign, create the hash table structure as @{}, and then add key-value pairs as <key> = <value>.

Now, on to a Read-Host example. Read-Host is a cmdlet that can be used to interactively prompt a user for a value. It’s not always preferred, or the right to do, but there are times when it can be useful, and where its use is acceptable. In the next example, we’ll create a single key-value pair ourselves, then we’ll prompt the user for a value to assign to the Number key. As you will also determine, when prompted, the word “five” is entered, and sure enough, the entry ends up as the value for the Number key in our hash table.

Remove-Variable -Name Params
$Params = @{
    Color = 'red'
    Number = Read-Host -Prompt 'Enter spelled out number'
}
$Params
Enter spelled out number: five

Name                           Value
----                           -----
Number                         five
Color                          red

This example was one of those “can I do this moments?” Sure, I was able to return the $Params hash table with the correct value in the Number key after having been prompted for that value. This occurred, as the hash table was being defined and built. I didn’t even know if that would work, but now we both know that it does.

In the next example, we try something even more obscure, but as suspected, it doesn’t work. We first assign the Random key the value of a Read-Host prompt. As we’ve seen, that does work. Next, while still creating keys and values, we take the value assigned to the Random key in the $Params hash table and attempt to assign it to the Number key, as well. Again, this doesn’t work. As suspected, we can’t use the $Params hash table until it’s done being created. It’s not a shock, but it was worth a try, of course.

Remove-Variable -Name Params
$Params = @{
    DayOfWeek = 'Friday'
    Random = Read-Host -Prompt 'Enter spelled out number'
    Number = $Params.Random
}
$Params
Enter spelled out number: three

Name                           Value                                                                                                                             
----                           -----                                                                                                                             
Random                         three
Number
DayOfWeek                      Friday

Even if this did work, I’m not sure how this would ever really serve a purpose, but it’s always worth trying something even if doesn’t seem plausible. And if it did work, I don’t expect that we’d even need duplicate values in different keys anyway, and that’s all we’d be doing. But all that said, we absolutely can use Read-Host to assign a value to a key in a hash table, as it’s being created.

Alright, that was it. Enjoy the week!