PowerShell hash table key issues - powershell

Question

Maybe I am doing it wrong, but when I try and reference a hash table member using the key, I get no results, however when I filter a .GetEnumerator() output with the same key, I get a result.
This doesn't work:
$year = "2015"
$msol_year_members_table = #{}
foreach ($member in $(Get-MsolGroupMember -GroupObjectId $(Get-MsolGroup | ?{ $_.DisplayName -eq $("Class of " + $year) }).ObjectId)) {
$msol_year_members_table[$member.ObjectId] = $member
}
foreach ($mb in $(Get-Mailbox -ResultSize Unlimited)) {
if ($msol_year_members_table.ContainsKey($($mb.ExternalDirectoryObjectId))) {
$msol_year_members_table[$($mb.ExternalDirectoryObjectId)]
}
}
Doing this works though:
foreach ($mb in $(Get-Mailbox -ResultSize Unlimited)) {
if ($result = $msol_year_members_table.GetEnumerator() | ?{ $_.Name -eq $($mb.ExternalDirectoryObjectId) }) {
$result
}
}
Any pointers would be appreciated - assuming it is some stupid mistake.

Answer 1

Are you sure you don't have a type mismatch between the keys and the test values?
When you use the .containskey() method, the argument value must be the same type as the key, but when you use the .getenumerator() method, the -eq test is going to try to coerce the .Name value and the test value to the same type for the operation:
$ht = #{
1 = 'one'
2 = 'two'
3 = 'three'
}
$ht['1']
$ht.GetEnumerator() |? { $_.name -eq '1'}
Name Value
---- -----
1 one

Answer 2

Here is my working code - just in case it helps anyone, I used it to assign address book policies for dir sync'd groups to Office 365 mailboxes:
# Years to be processed
$years = #("2015","2016","2017","2018","2019","2020","2021","2022","2023","2024","2025","2026","2027")
# Loop through each year and retrieve the members for the groups
$msol_year_members_table = #{}
foreach ($year in $years) {
foreach ($member in $(Get-MsolGroupMember -GroupObjectId $(Get-MsolGroup | ?{ $_.DisplayName -eq $("Class of " + $year) }).ObjectId)) {
$key = $member.ObjectId.ToString()
$msol_year_members_table[$key] = $member
}
}
# Loop through the mailboxes and set the mailbox poilicies for matching members
foreach ($mb in $(Get-Mailbox -ResultSize Unlimited)) {
$key = $mb.ExternalDirectoryObjectId.ToString()
if ($msol_year_members_table.ContainsKey($key)) {
$alias = $msol_year_members_table[$key].Alias; $alias_split = $alias.Split(".")
$year = $alias_split[$alias_split.Length-1)]
Set-Mailbox -Identity $alias -AddressBookPolicy $("Class of " + $year + " ABP")
}
}