How to search a collection with an array in Powershell - arrays

Question

I have an array of MailItems from Outlook. I want to search each mail item and return the Subject and a Category based on a list of search terms contained in an array - in the example called $searchArray.
For example:
$mailbox = "my.mailbox#example.com"
$outlook = New-Object -com Outlook.Application
$ns = $outlook.GetNamespace("MAPI")
$inbox = $ns.Folders.Item($mailbox).Folders.Item("Inbox")
$searchItems = $inbox.Folders.Item("MySubFolder").Folders.Item("MyNestedSubFolder").Items
$searchArray = (
"Category1", ("searchTerm1","searchTerm2","searchTerm3"),
"Category2", ("searchTerm4","searchTerm5"),
"Category3", ("searchTerm6")
)
foreach ($msg in $searchItems) {
$msg | select Subject, # <Category where email address contains one of the search terms>
}
I want to return the Subject, and then a column called Category which will look at the $msg.SenderEmailAddress and if any of the searchTerms in the $searchArray is contained within the address, return the category that had that search term in it.
For example if one of the SenderEmailAddress values was "searchTerm2#somewhere.com" then return Category1 as the Category.

Answer 1

I would flip that array on its head and create a hashtable from it. Then use the first matching search term as a lookup key for the category:
$searchArray = (
"Category1", ("searchTerm1","searchTerm2","searchTerm3"),
"Category2", ("searchTerm4","searchTerm5"),
"Category3", ("searchTerm6")
)
# Create hashtable
$searchTable = #{}
# Populate hash table with values from array
for($i=0;$i-lt$searchArray.Count;$i+=2){
foreach($term in $searchArray[$i+1])
{
$searchTable[$term] = $searchArray[$i]
}
}
# Select Category based on first matching search term
$msg |Select-Object Subject,#{Name="Category";Expression={
$sender = $_.SenderEmailAddress
$searchTable[$($searchTable.Keys |Where-Object{$sender -like "*$_*"} |Select -First 1)]
}
}

Answer 2

Still need to use a calculated expression just as Mathias did (It's really the simple way). However I wanted to show an approach where you had a custom object array for the $searchArray. If you were to tailor it from scratch it would look like this. I also converted the terms into regex pattern matches since you say they are unique. Only caveat there is you need to be sure that there are no regex meta-characters in your search terms.
$searchArray = (
[pscustomobject]#{
Category = "1"
Pattern = "searchTerm1|searchTerm2|searchTerm3"
},
[pscustomobject]#{
Category = "2"
Pattern = "searchTerm4|searchTerm5"
},
[pscustomobject]#{
Category = "3"
Pattern = "searchTerm6"}
)
foreach ($msg in $searchItems) {
$msg | select Subject, #{
Name="Category";
Expression={$searchArray | Where-Object{$msg.SenderEmailAddress -match $_.pattern } | Select-Object -ExpandProperty Category}
}
}
Solution is dependant on PowerShell 3.0 from the type accelerator [pscustomobject]. Could easily bring it back to 2.0 if need be.
To showcase similar structure using 2.0 and automatic conversion of you array to one that works with my code.
$newSearchArray = for($categoryIndex=0;$categoryIndex-lt$searchArray.Count;$categoryIndex+=2){
New-Object -TypeName pscustomobject -Property #{
Category = $searchArray[$categoryIndex]
Pattern = ($searchArray[$categoryIndex+1] | ForEach-Object{[regex]::Escape($_)}) -join "|"
}
}
Now the search terms are automatically escaped and joined into a search pattern.

Answer 3

Using a switch:
$mailbox = "my.mailbox#example.com"
$outlook = New-Object -com Outlook.Application
$ns = $outlook.GetNamespace("MAPI")
$inbox = $ns.Folders.Item($mailbox).Folders.Item("Inbox")
$searchItems = $inbox.Folders.Item("MySubFolder").Folders.Item("MyNestedSubFolder").Items
foreach ($msg in $searchItems) {
$object = $msg | select Subject,Category # <Category where email address contains one of the search terms>
Switch -Regex ($msg.SenderEmailAddress)
{
'searchTerm1|searchTerm2|searchTerm3' { $object.Catetory = 'Category1' ; break }
'searchTerm4|searchTerm5' { $object.Catetory = 'Category2' ; break }
'searchTerm6' { $object.Catetory = 'Category3' ; break }
}
$object
}