Parse out date from filename and sort by date - powershell

Question

I have a series of files named as such in a folder:
- myFile201801010703.file
I'm trying to parse out the yyyymmdd portion of each filename in the folder and sort them based on the date into an array.
So if I had the following files:
myFile201801200000.file (01/20/2018)
myFile201800100000.file (01/01/2018)
myFile201801100000.file (01/10/2018)
It would sort them into an array as such:
myFile201800100000.file (01/01/2018)
myFile201801100000.file (01/10/2018)
myFile201801200000.file (01/20/2018)
I have a process that works for file with timestamps included in the name, though have been unable to tweak it for work with only a date:
# RegEx pattern to parse the timestamps
$Pattern = '(\d{4})(\d{2})(\d{2})*\' + ".fileExtension"
$FilesList = New-Object System.Collections.ArrayList
$Temp = New-Object System.Collections.ArrayList
Get-ChildItem $SourceFolder | ForEach {
if ($_.Name -match $Pattern) {
Write-Verbose "Add $($_.Name)" -Verbose
$Date = $Matches[2],$Matches[3],$Matches[1] -join '/'
$Time = $Matches[4..6] -join ':'
[void]$Temp.Add(
(New-Object PSObject -Property #{
Date = [datetime]"$($Date) $($Time)" #If I comment out $($Time)it doesn't work.
File = $_
}
))
}
}
} catch {
Write-Host "`n*** $Error ***`n"
}
# Sort the files by the parsed timestamp and add to $FilesList
$FilesList.AddRange(#($Temp | Sort Date | Select -Expand File))
# Clear out the temp collection
$Temp.Clear()
The two lines in particular that I think might be culprit are:
$Time = $Matches[4..6] -join ':' Since I'm not parsing any time
Date = [datetime]"$($Date) $($Time)" Again, no time is parsed. Can't change the type to date either it seems?

Answer 1

With this format:
myFileYYYYMMddHHmm.file
the individual parts of the date and time is already arranged from largest (the year) to smallest (the minute) - this makes the string sortable!
Only thing we need to do is grab the last 12 digits of the file name before the extension:
$SortedArray = Get-ChildItem *.file |Sort-Object {$_.BaseName -replace '^.*(\d{12})$','$1'}
The regex pattern used:
^.*(\d{12})$
Can be broken down as follows:
^ # start of string
.* # any character, 0 or more times
( # capture group
\d{12} # any digit, 12 times
) # end of capture group
$ # end of string
The regex engine will expand $1 in the substitution string to "capture group #1", ie. the 12 digits we picked up at the end.