On Thu, Jan 23, 2014 at 12:27 PM, MRAB <pyt...@mrabarnett.plus.com> wrote: > On 2014-01-23 00:58, Larry Martell wrote: >> >> I have the need to check for a files existence against a string, but I >> need to do case-insensitively. I cannot efficiently get the name of >> every file in the dir and compare each with my string using lower(), >> as I have 100's of strings to check for, each in a different dir, and >> each dir can have 100's of files in it. Does anyone know of an >> efficient way to do this? There's no switch for os.path that makes >> exists() check case-insensitively is there? >> > You don't say which OS. Filenames in Windows, for example, are already > case-insensitive.
There are weird use-cases for case insensitive filename matching on a case sensitive file system. (For instance, a program that parses a playlist file created on Windows. I did that a while ago - had to map "Foobar.MID" to "FooBar.mid", matching case insensitively and retrieving the actual case used on the FS.) A good data structure is probably all you need. As Roy suggests, iterate once over the directories - for instance, create a dict mapping the .lower() of the filename to the original. Of course, then you have to worry about collisions... though you may be able to guarantee that they can't happen (in the above case, I was looking through a directory tree that was unzipped straight from the Windows collection, ergo no two filenames could differ only in case). Or maybe you *think* you can guarantee it, but due to a bug you can't. (Ever had a USB stick, formatted NTFS, with two files differing only in case? Windows XP behaves... oddly. And rather amusingly.) ChrisA -- https://mail.python.org/mailman/listinfo/python-list
