VBscript create array but omit blank variables - arrays

Question

I am looking to create a script that will compare the last modified date of up to 4 files then capture the one most recently modified. My current road block is that some files might not exist.
The set will fail if the file does not exist but I can easily overcome that by looking for the file and if it does not exist simply skip the set command. This would cause the creation of the array to fail because my variable is now blank.
Any suggestions how to resolve this?
Here is what I have so far:
Option Explicit
Dim objFSO, path, file, recentDate, recentFile, File1, File2, File3, File4, afiles, File1date, date1
Set objFSO = CreateObject("Scripting.FileSystemObject")
set File1=objFSO.getfile("c:\temp\file.txt")
set File2=objFSO.getfile("c:\test\File.txt")
set File3=objFSO.getfile("c:\users\%profile%\documents\File.txt")
set File4=objFSO.getfile("c:\users\public\documents\File.txt")
'Prepare variables to store the required information
Dim dateMin, dateMax
date1 = File1.datelastmodified
wscript.echo date1
wscript.echo now
dateMin = date1
dateMax = date1
afiles = Array( File1.datelastmodified, File2.datelastmodified, File3.datelastmodified, File4.datelastmodified )
Dim i
For i=1 to UBound(aFiles)
If aFiles(i) < dateMin Then dateMin = aFiles(i)
if aFiles(i) > dateMax Then dateMax = aFiles(i)
Next
'
' Output Information
WScript.Echo "Highest: " & CStr( dateMax )
WScript.Echo " Lowest: " & CStr( dateMin )

Answer 1

I think this would be much easier if you use an ArrayList to capture the DateLastModified for each file.
An ArrayList lets you dynamically add values unlike a VBScript Array.
Furthermore, the ArrayList has a very useful method called Sort() we can use here to determine the dateMin and dateMax values.
Try:
Option Explicit
Dim objFSO, objList, objFile, arrFiles, fileName
arrFiles = Array("c:\temp\file.txt","c:\test\File.txt","c:\users\%profile%\documents\File.txt","c:\users\public\documents\File.txt")
Set objList = CreateObject("System.Collections.ArrayList")
Set objFSO = CreateObject("Scripting.FilesystemObject")
For Each fileName In arrFiles
If objFSO.FileExists(fileName) Then
Set objFile = objFSO.GetFile(fileName)
objList.Add objFile.DateLastModified
End If
Next
objList.Sort()
' Prepare variables to store the required information
Dim dateMin, dateMax
dateMin = objList.item(0)
dateMax = objList.item(objList.Count - 1)
' Output Information
WScript.Echo "Highest: " & CStr( dateMax )
WScript.Echo "Lowest: " & CStr( dateMin )
' Clean up
Set objFSO = Nothing
Set objFile = Nothing
Set objList = Nothing
Edit
The above code was a remake of your original code. I may have misunderstood then that your goal is to find the file most recently modified.
This should do what you have in mind:
Option Explicit
Dim objFSO, objFile, objLatest, fileName, arrFiles
arrFiles = Array("c:\temp\file.txt","c:\test\File.txt","c:\users\%profile%\documents\File.txt","c:\users\public\documents\File.txt")
Set objFSO = CreateObject("Scripting.FilesystemObject")
Set objLatest = Nothing
For Each fileName In arrFiles
If objFSO.FileExists(fileName) Then
Set objFile = objFSO.GetFile(fileName)
If (objLatest Is Nothing) Then
Set objLatest = objFile
ElseIf (objFile.DateLastModified > objLatest.DateLastModified) Then
Set objLatest = objFile
End If
End If
Next
If objLatest Is Nothing Then
WScript.Echo "None of the files in 'arrFiles' exist.."
Else
' Here you decide if you want to keep the latest file as Object (-> objLatest) or just as a string to the full pathname of that file
Dim latestFile
latestFile = objFSO.GetAbsolutePathName(objLatest) ' store the full path and filename
' Info on FormatDateTime() at https://www.w3schools.com/asp/func_formatdatetime.asp
WScript.Echo "Most recently modified file is '" & latestFile & "' at " & FormatDateTime(objLatest.DateLastModified, 0)
End If
' Clean up
Set objFSO = Nothing
Set objFile = Nothing
Set objLatest = Nothing