Store deduplicated list of non-ascii characters in array - arrays

Question

I have many textfiles containing extended ascii characters. I would like to build a deduplicated list of these characters, for instance:
á
ö
¿
I am able to read files and strip out the basic ascii characters. However, since I am new to Powershell, how can I break each line into characters, compare them to an existing list of characters found and output a deduplicated list of non-basic ascii chars?
$files = Get-ChildItem "C:\Users\me\Desktop\ascii" -filter "*.txt"
Foreach ($file in $files) {
$newfile = #()
Get-Content $file.fullname | Foreach-Object {
$newfile += [string]([char[]]$_ | where-object {[int]$_ -lt 127})
}
Write-Host $newfile
}
[edit 1] Getting there...
$files = Get-ChildItem "C:\Users\me\Desktop\ascii" -filter "*.txt"
$array = #()
Foreach ($file in $files) {
Get-Content $file.fullname | Foreach-Object {
$line = [string]([char[]]$_ | where-object {[int]$_ -lt 127}) -split '\s+' | Foreach {
If ($array -notcontains $_) {
$array.Add($_)
}
}
}
}
[edit 2] This ^^^ works in PS 4 but not in 2 (which I have on my server)? Any help in writing the PS2 compatible version of this?
[edit 3] I found out that using $array = #() works fine on V2 and V4 :-)

Answer 1

Perhaps I'm missing something, but shouldn't you check for values greater than 127 if you're building a list of extended ASCII characters?
This should give you a list of extended ASCII characters from all files without duplicates:
Get-ChildItem 'C:\Users\me\Desktop\ascii' -filter '*.txt' |
Get-Content |
% { [char[]]$_ } |
? { [int]$_ -gt 127 } |
select -Unique

Answer 2

Any help? (requires V3)
$string = 'áTestáöö¿'
$ht = #{}
$basic,$extended = ([char[]]$string).Where({[int]$_ -lt 127},'Split')
$extended | foreach {$ht[$_] += $null}
[string]$basic
$ht.keys
T e s t
¿
ö
á