Finding a file that has highest number in the filename using powershell - powershell

Question

Sorry guys..I am new to powershell. Would be great if someone help with the following scenario:
I have couple of files in a folder c:\test
sample.x.x.1
sample.x.x.2
sample.x.x.3
sample.x.x.4
sample.x.x.5
I want to find the name of the file which has the highest number in its name in the given folder. In the above example, 5 is the highest number and the script should return the output filename as sample.x.x.5
Thanks in advance!

Answer 1

Sorting file names with numbers is quite a problem, as there are two ways. The first one sets them to alphabetical order. That is, 0, 1, 11, 111, 2,... The second one uses natural order. That is, 0, 1, 2, 11, 111.... This is surprisingly tricky and about every third programmer is confused with this.
There's a good answer already, which I'll refer like so,
# Create files 1..5
for($i=1;$i -le 5; ++$i) { set-content sample.x.x.$i -Value $null }
# Tricksy! Create file .10 to confuse asciibetic/natural sorting
set-content sample.x.x.10 -Value $null
ls # Let's see the files
Directory: C:\temp\test
Mode LastWriteTime Length Name
---- ------------- ------ ----
-a---- 2015-09-28 10:29 0 sample.x.x.1
-a---- 2015-09-28 10:29 0 sample.x.x.10
-a---- 2015-09-28 10:29 0 sample.x.x.2
-a---- 2015-09-28 10:29 0 sample.x.x.3
-a---- 2015-09-28 10:29 0 sample.x.x.4
-a---- 2015-09-28 10:29 0 sample.x.x.5
# Define helper as per linked answer
$ToNatural = { [regex]::Replace($_, '\d+$', { $args[0].Value.PadLeft(20,"0") }) }
# Sort with helper and check the output is natural result
gci | sort $ToNatural -Descending | select -First 1
Directory: C:\temp\test
Mode LastWriteTime Length Name
---- ------------- ------ ----
-a---- 2015-09-28 10:29 0 sample.x.x.10

Answer 2

Alphabetical sorting.
PS C:\Users\Gebb> #("sample.x.x.1", "sample.x.x.5", "sample.x.x.11") | sort
sample.x.x.1
sample.x.x.11
sample.x.x.5
Numerical sorting.
PS C:\Users\Gebb> #("sample.x.x.1", "sample.x.x.5", "sample.x.x.11") |
sort -Property #{Expression={[Int32]($_ -split '\.' | select -Last 1)}}
sample.x.x.1
sample.x.x.5
sample.x.x.11
Largest number.
PS C:\Users\Gebb> #("sample.x.x.1", "sample.x.x.5", "sample.x.x.11") |
sort -Property #{Expression={[Int32]($_ -split '\.' | select -Last 1)}} |
select -Last 1
sample.x.x.11