[Python-ideas] PEP 428 - object-oriented filesystem paths

[Massimo DiPierro]

I was thinking of the api more than the implementation.
The point to me is that it would be nice to have something the behaves as a string and as a list at the same time. 
Here is another possible incomplete implementation.

import os
class Path(object):
    def __init__(self,s='/',sep=os.path.sep):
        self.sep = sep
        self.s = s.split(sep)
    def __str__(self):
        return self.sep.join(self.s)
    def __add__(self,other):
        if other[0]=='':
            return Path(other)
        else:
            return Path(str(self)+os.sep+str(other))
    def __getitem__(self,i):
        return self.s[i]
    def __setitem__(self,i,v):
        self.s[i] = v
    def append(self,v):
        self.s.append(v)
    @property
    def filename(self):
        return self.s[-1]
    @property
    def folder(self):
        return Path(self.sep.join(self.s[:-1]))

>>> path = Path('/this/is/an/example.png')
>>> print path[-1]
example.png
>>> print path.filename
example.png
>>> print path.folder
/this/is/an
>>> path[1]='that'
/that/is/an/example.png
>>> print path.folder + 'this'
/that/is/an/this


On Oct 6, 2012, at 12:51 PM, Georg Brandl wrote:

> Am 06.10.2012 19:32, schrieb Massimo DiPierro:
>> How about something along this lines:
>> 
>> import os
>> 
>> class Path(str):
>>    def __add__(self,other):
>>        return Path(self+os.path.sep+other)
>>    def __getitem__(self,i):
>>        return self.split(os.path.sep)[i]
>>    def __setitem__(self,i,v):
>>        items = self.split(os.path.sep)
>>        items[i]=v
>>        return Path(os.path.sep.join(items))
>>    def append(self,v):
>>        self += os.path.sep+v
>>    @property
>>    def filename(self):
>>        return self.split(os.path.sep)[-1]
>>    @property
>>    def folder(self):
>>        items =self.split(os.path.sep)
>>        return Path(os.path.sep.join(items[:-1]))
>> 
>> path = Path('/this/is/an/example.png')
>> print isinstance(path,str) # True
>> print path[-1] # example.png
>> print path.filename # example.png
>> print path.folder # /this/is/an
> 
> If you inherit from str, you cannot override any of the operations that
> str already has (i.e. __add__, __getitem__).  And obviously you also
> can't make it mutable, i.e. __setitem__.
> 
> Georg
> 
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