Today I had to check whether a path object started with `/foo`. The nicest way I could think of was `str(p).startswith('/foo')`. What do you think about implementing `p.startswith('/foo')`?

Do you mean that /foo was just an arbitrary string, rather than one of the parent directories? Because in that case it seems a perfectly correct way to go about comparison. If /foo was one of the parents, there are plenty of options: .parts, .parents, .relative_to.

It seems like a fairly rare usecase to extend the api.

I mean that `/foo` is one of the parent directories.

"there are plenty of options ..." Can you please spell them out precisely? The full line of code.

>>> from pathlib import Path
>>> p = Path('/foo/bar')
>>> Path('/foo') in p.parents
True
>>> Path('/spam') in p.parents
False
>>> p.parts[:2] == ('/', 'foo')
True
>>> p.parts[:2] == ('/', 'spam')
False
>>> p.relative_to('/foo')
PosixPath('bar')
>>> p.relative_to('/spam')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/lib/python3.5/pathlib.py", line 864, in relative_to
    .format(str(self), str(formatted)))
ValueError: '/foo/bar' does not start with '/spam'

Thanks.