powershell check directory for files - file

Question

I have a folder that should contain 10 files. Each file name will be different (name and extension), however, it will contain a pattern.
eg.
SomeThing.FILE0.DAT
SomeThing.FILE1.DAT
SomeThing.FILE2.DAT
and so on till
SomeThing.FILE9.DAT
My script currently does not have any checks. I manually run it ensuring that all files are present.
for ($i=0; $i -le 9; $i++)
{
$FileString = "*FILE"+$i+"*"
$MyFileName = Get-ChildItem e:\files -name -filter $($FileString)
}
However, I need to automate the process, so I want to add checks to make sure that:
a. Total of 10 files exist in that folder
$FC = ( Get-ChildItem c:\testing | Measure-Object ).Count;
if($FC -eq 10)
{
echo "File Count is correct"
}
else
{
echo "File Count is incorrect"
}
b. Each of the FILEX (X = 0-9) are present
c. Only one instance of each FILEX (X = 0-9) should be present. If multiple instances of FILEX are present, I need to display it on the screen saying that FILEX pattern is repeated multiple times.
How can I do these remaining checks? It looked simple, but is more complicated...

Answer 1

$> if ((compare (ls -name | %{ ([regex]'(?<=.*FILE).*(?=.DAT)').match($_).groups[0].value } | Sort-Object) (0..9 | %{$_.ToString()}) -SyncWindow 0).Length -eq 0) { Write-Host "ok" }
ok
Uh?
Rephrasing your question we have something like "check that directory contains only *FILEX.DAT files, where X should be every possible number between 0 and 9". In powershell it should look something like that:
$> if (allNumbersFromFileNames.IsEqualTo(0..9)) { Write-Info "ok" }
To get all numbers from filenames from the current directory:
$> ls -name | %{ ([regex]'(?<=.*FILE).*(?=.DAT)').match($_).groups[0].value }
0
1
2
3
5
6
7
8
9
4
We've constructed regex here with ([regex]'(?<=.*FILE).*(?=.DAT)') and for every filename in current directory (ls -name | %{ $_ }) parse the magic number in it and get a first matched group's value.
Finally we need to have this string[] object, sort it and compare with array of strings of numbers. compare could be useful here.
I.e.
$> if ((compare 0..9 1..4).Length -eq 0) { Write-Host "equals" }
$> if ((compare 0..9 0..9).Length -eq 0) { Write-Host "equals" }
equals
Put it all together and you have an answer!

Answer 2

Since the regex solution did not work for me, i ended you writing a crude logic. So far it works. If anything better is available, please advise.
for ($i=0; $i -le 9; $i++)
{
$FileString = "*FILE"+$i+"*"
$ct = (Get-ChildItem "C:\testing" -name -filter $($FileString) | Measure-Object ).Count
if($ct -ne 1)
{
if($ct -eq 0)
{
write-host "FILE"$i "is missing"
}
elseif ($ct -gt 1)
{
write-host $ct" instances of FILE"$i" found"
}
else
{
write-host "God help you."
}
}
}