get file extension from file name

Getting Started
1

Maybe a stupid question, but I don’t see a function to do this…

Is there an easy way to pull the extension out of a file name?
Or should I just take the characters after the last dot?

thanks

gert

2

Yes, you need your own function. There are a number of ways to do it, but this should work.

dim ext as string

dim parts() as string = filename.Split( "." )
if parts.Ubound > 0 and parts( 0 ) <> "" then
  dim lastPart as string = parts.Pop
  if lastPart.InStr( " " ) = 0 then
    ext = lastPart
  end if
end if

return ext

If a file starts with a dot, it will not be considered an extension. Note too that if the last part contains a space, it will not be considered an extension. This matches what the Finder on the Mac but might not meet your requirements.

3

If you have MBS plugins you can use folderitem.nameextensionMBS.

Else characters after the last dot.

There are many variants of this, but I use this to get the last dot position.

Function InstrRev(Instring as string, Delim as string) As Integer Dim i as integer If instr(Instring,delim) < 1 then return 0 end if For i=len(Instring) downto 1 If instr(i,Instring,delim) > 0 then return instr(i,Instring,delim) end if next return 0 End Function

4

Or this regular expression pattern. :slight_smile:

^[^.].*\\.\\K\\S+
5

Thanks a lot, all. All this is working fine!
Stupid I spent so much time looking for a function because I did not know it did not exist.
Grateful for your fast reply, all.

6

You can also create an Extends method in a module so this can become a “part” of FolderItem.

In a module, create the following method as Global:

Function NameExtension (Extends f As FolderItem) As String
  dim ext as string

  dim parts() as string = f.Name.Split( "." )
  if parts.Ubound > 0 and parts( 0 ) <> "" then
    dim lastPart as string = parts.Pop
    if lastPart.InStr( " " ) = 0 then
      ext = lastPart
    end if
  end if

  return ext
End Function

Then you can do things like “ext = f.NameExtension”.

2 Likes
7

[quote=263057:@Kem Tekinay]Or this regular expression pattern. :slight_smile:

^[^.].*\\.\\K\\S+ [/quote]

Showoff! :wink:

8

Thanks all !

I was yesterday in the exact inverse: I wanted the file name without the extension. My previous code was (stupid) buggy: I certainly was in a hurry when I coded it… (if there is a home url in the file name - to set the source of the data in the file - the dots in it displayed the bug [or simply a dot inthe file name that is not the one before the extension).

The process to remove the extension was to detect where it is ;-:slight_smile:

Then, I used left to get what I wanted !