Collecting Unique Items from large data set over multiple text files - powershell

Question

I am using PowerShell to collect lists of names from multiple text files. May of the names in these files are similar / repeating. I am trying to ensure that PowerShell returns a single text file with all of the unique items. In looking at the data it looks like the script is gathering 271/296 of the unique items. I'm guessing that some of the data is being flagged as duplicates when it shouldn't, any suggestions?
#Take content of each file (all names) and add unique values to text file
#for each unique value, create a row & check to see which txt files contain
function List {
$nofiles = Read-Host "How many files are we pulling from?"
$data = #()
for ($i = 0;$i -lt $nofiles; $i++)
{
$data += Read-Host "Give me the file name for file # $($i+1)"
}
return $data
}
function Aggregate ($array) {
Get-Content $array | Sort-Object -unique | Out-File newaggregate.txt
}
#SCRIPT BODY
$data = List
aggregate ($data)
I was expecting this code to catch everything, but it's missing some items that look very similar. List of missing names and their similar match:
CORPINZUTL16 MISSING FROM OUTFILE
CORPINZTRACE MISSING FROM OUTFILE
CORPINZADMIN Found In File
I have about 20 examples like this one. Apparently the Get-Content -Unique is not checking every character in a line. Can anyone recommend a better way of checking each line or possibly forcing the get-character to check full names?

Answer 1

Just for demonstration this line creates 3 txt files with numbers
for($i=1;$i -lt 4;$i++){set-content -path "$i.txt" -value ($i..$($i+7))}
1.txt | 2.txt | 3.txt | newaggregate.txt
1 | | | 1
2 | 2 | | 2
3 | 3 | 3 | 3
4 | 4 | 4 | 4
5 | 5 | 5 | 5
6 | 6 | 6 | 6
7 | 7 | 7 | 7
8 | 8 | 8 | 8
| 9 | 9 | 9
| | 10 | 10
Here using Get-Content with a range [1-3] of files
Get-Content [1-3].txt | Sort-Object {[int]$_} -Unique | Out-File newaggregate.txt
$All = Get-Content .\newaggregate.txt
foreach ($file in (Get-ChildItem [1-3].txt)){
Compare-Object $All (Get-Content $file.FullName) |
Select-Object #{n='File';e={$File}},
#{n="Missing";e={$_.InputObject}} -ExcludeProperty SideIndicator
}
File Missing
---- -------
Q:\Test\2019\05\07\1.txt 9
Q:\Test\2019\05\07\1.txt 10
Q:\Test\2019\05\07\2.txt 1
Q:\Test\2019\05\07\2.txt 10
Q:\Test\2019\05\07\3.txt 1
Q:\Test\2019\05\07\3.txt 2

Answer 2

there are two ways to achieve this one is using select-object -Unique which works when data is not sorted and can be used for small data or lists.
When dealing with large files we can use get-Unique command which works with sorted input, if input data is not sorted then it will give wrong results.
Get-ChildItem *.txt | Get-Content | measure -Line #225949
Get-ChildItem *.txt | Get-Content | sort | Get-Unique | measure -Line #119650
Here is my command for multiple files :
Get-ChildItem *.txt | Get-Content | sort | Get-Unique >> Unique.txt