On 26/05/2020 16:59, Mats Wichmann wrote: > On 5/26/20 8:56 AM, BlindAnagram wrote: >> I came across an issue that I am wondering whether I should report as an >> issue. If I have a directory, say: >> >> base='C:\\Documents' >> >> and I use os.path.join() as follows: >> >> join(base, '..\\..\\', 'build', '') >> >> I obtain as expected from the documentation: >> >> 'C:\\Documents\\..\\..\\build\\' >> >> But if I try to make the directory myself (as I tried first): >> >> join(base, '..\\..\\', 'build', '\\') >> >> I obtain: >> >> 'C:\\' >> >> The documentation says that an absolute path in the parameter list for >> join will discard all previous parameters but '\\' is not an absoute path! > > But it is - an absolute path is one that starts with the pathname separator.
On Windows, when part of a string representing a file or directory path, '\\' acts as a directory separator. It may imply, as you say, that it is a path on the current drive but it also behaves as a move to a sub-directory of what has appeared to its left. And this is how it is treated in other os.path functions. For example: base = "C:\\Documents\\Finance\\" abspath(base) 'C:\\Documents\\Finance' where it can be seen that '\\' is being treated as a directory separator. In my view it is not sensible to have some functions treating '\\' in one way and others differently. I would hence expect join() to accept '\\' as an addition to a file path on Windows and not a signal of an absolute path. > The concept of paths is ugly in Windows because of the drive letter - a > drive letter is not actually part of a path, it's an additional piece of > context. If you leave out the drive letter, your path is relative or > absolute within the current drive letter; if you include it your path is > relative or absolute within the specified drive letter. So Python has > behaved as documented here: the indicator for an absolute path has > discarded everything (except the drive letter, which is necessary to > maintain the context you provided) which came before it in the join. > > If indeed you're seeking a path that is terminated by the separator > character, you need to do what you did in the first example - join an > empty string at the end (this is documented). The terminating separator > _usually_ isn't needed. Sadly, sometimes it appears to be... I agree that handling file paths on Windows is very ugly, especially so if some of the directory/file names include spaces. But I don't see that as an excuse for this specific ambiguity in Python in the handling of '\\' when embedded in, or added to, paths. -- https://mail.python.org/mailman/listinfo/python-list
