hash table/pscustomobject instead of switch block - hashtable

Question

Is there a way to use hash table or pscustomobject instead of switch block below? hash table seems like a great way to simplify the function.
function Get-Farm
{
[cmdletbinding()]
param (
[parameter (Mandatory = $true)]
[string]$farm)
Process{
switch($farm){
A {
$script:startHostID = 0
$script:endHostID = 0
}
B {
$script:startHostID = 1
$script:endHostID = 12
}
C {
$script:startHostID = 13
$script:endHostID = 24
}
BC {
$script:startHostID = 1
$script:endHostID = 24
}
ALL {
$script:startHostID = 1
$script:endHostID =48
}
}
}

Answer 1

Indeed, hashtable lookup is a better alternative.
Create the lookup table in Begin block and use it in Process.
Also, use ValueFromPipeline in parameter description, otherwise don't use Process.
function Get-Farm
{
[cmdletbinding()]
param (
[parameter(Mandatory, ValueFromPipeline)]
[string]$farm
)
Begin {
$lookup = #{
A = 0,0
B = 1,12
C = 13,24
BC = 1,24
ALL = 1,48
}
}
Process {
if ($values = $lookup[$farm]) {
$script:startHostID = $values[0]
$script:endHostID = $values[1]
}
}
}
I've used the assignment inside if() to condense the code but of course you can write it separately:
$values = $lookup[$farm]
if ($values) {