This is documentation for Mathematica 7, which was
based on an earlier version of the Wolfram Language.
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FileExtension

FileExtension["file"]
gives the file extension for a file name.
  • FileExtension gives the extension that appears after the last . in a file name.
  • If there are multiple endings to a file name, separated by ., FileExtension gives only the last one.
  • FileExtension gives "" if there is no file extension, if the file name has the form of a directory name, or ends with a . character.
  • FileExtension by default assumes pathname separators and other conventions suitable for your operating system.
  • FileExtension[..., OperatingSystem->"os"] uses the conventions of the specified operating system. Possible choices are "Windows", "MacOSX" and "Unix".
  • FileExtension just operates on names of files; it does not actually search for the file specified.
Find the file extension of a string:
Find the file extension of a string:
In[1]:=
Click for copyable input
Out[1]=
The period is not part of the file extension:
Or the file base name:
New in 7