Why doesn't os.path.join() work in this case?

python path
chrisg picture chrisg · Dec 22, 2009 · Viewed 510.4k times · Source

The below code will not join, when debugged the command does not store the whole path but just the last entry.

os.path.join('/home/build/test/sandboxes/', todaystr, '/new_sandbox/')

When I test this it only stores the /new_sandbox/ part of the code.

Answer

Craig McQueen picture Craig McQueen · Dec 22, 2009

The latter strings shouldn't start with a slash. If they start with a slash, then they're considered an "absolute path" and everything before them is discarded.

Quoting the Python docs for os.path.join:

If a component is an absolute path, all previous components are thrown away and joining continues from the absolute path component.

Note on Windows, the behaviour in relation to drive letters, which seems to have changed compared to earlier Python versions:

On Windows, the drive letter is not reset when an absolute path component (e.g., r'\foo') is encountered. If a component contains a drive letter, all previous components are thrown away and the drive letter is reset. Note that since there is a current directory for each drive, os.path.join("c:", "foo") represents a path relative to the current directory on drive C: (c:foo), not c:\foo.

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