powershell - extract file name and extension

Question

I need to extract file name and extension from e.g. my.file.xlsx. I don't know the name of file or extension and there may be more dots in the name, so I need to search the string from the right and when I find first dot (or last from the left), extract the part on the right side and the part on the left side from that dot.

How?

Answer 1

If the file is coming off the disk and as others have stated, use the BaseName and Extension properties:

PS C:\> dir *.xlsx | select BaseName,Extension

BaseName                                Extension
--------                                ---------
StackOverflow.com Test Config           .xlsx  

If you are given the file name as part of string (say coming from a text file), I would use the GetFileNameWithoutExtension and GetExtension static methods from the System.IO.Path class:

PS C:\> [System.IO.Path]::GetFileNameWithoutExtension("Test Config.xlsx")
Test Config
PS H:\> [System.IO.Path]::GetExtension("Test Config.xlsx")
.xlsx