Please help me finding a way to implement os.path.issubpath(a, b)

[Giampaolo Rodola']

Hi,
I'm trying to implement a function which returns whether a path is a
subpath of another one (e.g. /a/b/c is a subpath of /a/b).
I wrote this function which apparently seems to work fine:

import os

def issubpath(path1, path2):
"""Return True if path1 is a sub path of path2."""
if path1 == path2:
return False
x1 = path1.split(os.sep)
x2 = path2.split(os.sep)
return x1[:len(x2)] == x2

....but if I use "issubpath('C:\\dir', 'C:\\')" it returns False.
A little help would be appreciated.

Thanks in advance.
--- Giampaolo
http://code.google.com/p/pyftpdlib/

[Arnaud Delobelle]

On Sep 11, 5:40*pm, "Giampaolo Rodola'" <[e-mail]:

Hi,
I'm trying to implement a function which returns whether a path is a
subpath of another one (e.g. /a/b/c is a subpath of /a/b).
I wrote this function which apparently seems to work fine:

import os

def issubpath(path1, path2):
* * """Return True if path1 is a sub path of path2."""
* * if path1 == path2:
* * * * return False
* * x1 = path1.split(os.sep)
* * x2 = path2.split(os.sep)
* * return x1[:len(x2)] == x2

...but if I use "issubpath('C:\\dir', 'C:\\')" it returns False.
A little help would be appreciated.

Thanks in advance.

That's because:

>>'C:\\dir'.split('\\')

['C:', 'dir']

>>'C:\\'.split('\\')

['C:', '']

So you could write instead something like

x1 = path1.rstrip(os.sep).split(os.sep)
x2 = path2.rstrip(os.sep).split(os.sep)

in your function

HTH

--
Arnaud

[Diez B. Roggisch]

Giampaolo Rodola' schrieb:

Hi,
I'm trying to implement a function which returns whether a path is a
subpath of another one (e.g. /a/b/c is a subpath of /a/b).
I wrote this function which apparently seems to work fine:

import os

def issubpath(path1, path2):
"""Return True if path1 is a sub path of path2."""
if path1 == path2:
return False
x1 = path1.split(os.sep)
x2 = path2.split(os.sep)
return x1[:len(x2)] == x2

...but if I use "issubpath('C:\\dir', 'C:\\')" it returns False.
A little help would be appreciated.

Any reason why

os.path.normpath(a).startswith(os.normpath(b)) doesn't do the trick?

Diez

[Fredrik Lundh]

Diez B. Roggisch wrote:

Any reason why

os.path.normpath(a).startswith(os.normpath(b)) doesn't do the trick?

Except for the trivial type, you mean? That depends on whether "c:\foo"
should be seen as a subpath to "c:\foobar" or not. I'd probably go for
(also untested):

def issubpath(a, b):
def fixpath(p):
return os.path.normpath(p) + os.sep
return fixpath(a).startswith(fixpath(b))

</F>

[Giampaolo Rodola']

On Sep 11, 8:04*pm, Arnaud Delobelle <[e-mail]:

On Sep 11, 5:40*pm, "Giampaolo Rodola'" <[e-mail]:

Hi,
I'm trying to implement a function which returns whether a path is a
subpath of another one (e.g. /a/b/c is a subpath of /a/b).
I wrote this function which apparently seems to work fine:

import os

def issubpath(path1, path2):
* * """Return True if path1 is a sub path of path2."""
* * if path1 == path2:
* * * * return False
* * x1 = path1.split(os.sep)
* * x2 = path2.split(os.sep)
* * return x1[:len(x2)] == x2

...but if I use "issubpath('C:\\dir', 'C:\\')" it returns False.
A little help would be appreciated.

Thanks in advance.

That's because:

>'C:\\dir'.split('\\')

['C:', 'dir']

>'C:\\'.split('\\')

['C:', '']

So you could write instead something like

* * x1 = path1.rstrip(os.sep).split(os.sep)
* * x2 = path2.rstrip(os.sep).split(os.sep)

in your function

HTH

--
Arnaud

Thanks, it seems to work just fine.
--- Giampaolo
http://code.google.com/p/pyftpdlib/