directory listing

[SU News Server]

I've struggled with this for quite a while and I'm am just not sure
what is going on. I have the following code
import os

def buildList( directory='/Users/mkonrad' )

dirs = [ ]

listing = os.listdir(dire ctory)

for x in listing:
if os.path.isdir(x ):
dirs.append(x)

return dirs

This always returns an empty list.
Now if I change it so that directory='.' or directory=os.ge tcwd()
Then it returns a list of directories.

Any ideas?

Thank you,
-Michael

[Fredrik Lundh]

Re: directory listing

"SU News Server" <mkonrad@syr.ed u> wrote:
[color=blue]
> I've struggled with this for quite a while and I'm am just not sure
> what is going on. I have the following code
> import os
>
> def buildList( directory='/Users/mkonrad' )
>
> dirs = [ ]
>
> listing = os.listdir(dire ctory)
>
> for x in listing:
> if os.path.isdir(x ):
> dirs.append(x)
>
> return dirs
>
> This always returns an empty list.
> Now if I change it so that directory='.' or directory=os.ge tcwd()
> Then it returns a list of directories.[/color]

hint: if you're not sure what's going on in your program, adding
a print statement or two is an easy way to figure it out. like, say:

for x in listing:
print x
if os.path.isdir(x ):
dirs.append(x)

(try this before you continue)

:
:
:

the problem is that os.listdir returns a list of filenames, without
the preceeding directory name. you can add an os.path.join

for x in listing:
x = os.path.join(di rectory, x)
if os.path.isdir(x ):
dirs.append(x)

or use the glob module instead:

listing = glob.glob(os.pa th.join(directo ry, "*"))

hope this helps!

</F>

[Richard Townsend]

Re: directory listing

On 11 Nov 2005 21:20:33 GMT, SU News Server wrote:

Try passing the full pathname of each item to os.path.isdir()

You can create the pathname using os.path.join(di rectory, x)


--
Richard

[Michael Konrad]

Re: directory listing

"Fredrik Lundh" <fredrik@python ware.com> wrote:
[color=blue]
> "SU News Server" <mkonrad@syr.ed u> wrote:
>[color=green]
>> I've struggled with this for quite a while and I'm am just not sure
>> what is going on. I have the following code
>> import os
>>
>> def buildList( directory='/Users/mkonrad' )
>>
>> dirs = [ ]
>>
>> listing = os.listdir(dire ctory)
>>
>> for x in listing:
>> if os.path.isdir(x ):
>> dirs.append(x)
>>
>> return dirs
>>
>> This always returns an empty list.
>> Now if I change it so that directory='.' or directory=os.ge tcwd()
>> Then it returns a list of directories.[/color]
>
> hint: if you're not sure what's going on in your program, adding
> a print statement or two is an easy way to figure it out. like, say:
>
> for x in listing:
> print x
> if os.path.isdir(x ):
> dirs.append(x)
>[/color]

Did that and I was just getting a bunch of [ ].
[color=blue]
> (try this before you continue)
>
> :
> :
> :
>
> the problem is that os.listdir returns a list of filenames, without
> the preceeding directory name. you can add an os.path.join
>
> for x in listing:
> x = os.path.join(di rectory, x)
> if os.path.isdir(x ):
> dirs.append(x)[/color]

OK. This works except each entry in dirs now includes the full path.
Is there an unjoin? :) I haven't spent any time trying to work this out.
[color=blue]
>
> or use the glob module instead:
>
> listing = glob.glob(os.pa th.join(directo ry, "*"))
>
> hope this helps!
>
> </F>
>
>
>
>[/color]

[Michael Konrad]

Re: directory listing

Richard Townsend <richard@nospam .com> wrote:
[color=blue]
> On 11 Nov 2005 21:20:33 GMT, SU News Server wrote:
>
> Try passing the full pathname of each item to os.path.isdir()
>
> You can create the pathname using os.path.join(di rectory, x)
>
>
>[/color]

I wonder if I can join ./, so I don't have the full path in each
entry?

Thank you for responding.
_Michael

[Richard Townsend]

Re: directory listing

On 11 Nov 2005 22:00:04 GMT, Michael Konrad wrote:
[color=blue]
> Richard Townsend <richard@nospam .com> wrote:
>[color=green]
>> On 11 Nov 2005 21:20:33 GMT, SU News Server wrote:
>>
>> Try passing the full pathname of each item to os.path.isdir()
>>
>> You can create the pathname using os.path.join(di rectory, x)
>>
>>
>>[/color]
>
> I wonder if I can join ./, so I don't have the full path in each
> entry?
>
> Thank you for responding.
> _Michael[/color]

Why not assign the os.path.join() result to a new variable, pass that to
os.path.isdir() but still append x to the list?


--
Richard

[Fredrik Lundh]

Re: directory listing

Michael Konrad wrote:
[color=blue][color=green]
> > for x in listing:
> > print x
> > if os.path.isdir(x ):
> > dirs.append(x)
> >[/color]
>
> Did that and I was just getting a bunch of [ ].[/color]

if you printed "x" (the filename), that doesn't sound very likely.
maybe you printed some other variable? (like "dirs")
[color=blue][color=green]
> > for x in listing:
> > x = os.path.join(di rectory, x)
> > if os.path.isdir(x ):
> > dirs.append(x)[/color]
>
> OK. This works except each entry in dirs now includes the full path.
> Is there an unjoin? :)[/color]

use two variables:

for name in listing:
fullname = os.path.join(di rectory, name)
if os.path.isdir(f ullname):
dirs.append(nam e)

</F>

[Shi Mu]

Re: directory listing

On 11 Nov 2005 22:00:04 GMT, Michael Konrad <mkonrad@syr.ed u> wrote:[color=blue]
> Richard Townsend <richard@nospam .com> wrote:
>[color=green]
> > On 11 Nov 2005 21:20:33 GMT, SU News Server wrote:
> >
> > Try passing the full pathname of each item to os.path.isdir()
> >
> > You can create the pathname using os.path.join(di rectory, x)
> >
> >
> >[/color]
>
> I wonder if I can join ./, so I don't have the full path in each
> entry?
>
> Thank you for responding.
> _Michael
>
>
> --
> http://mail.python.org/mailman/listinfo/python-list
>[/color]
I tried this and no error reported but nothing appear on the console, why?

import os

def buildList( directory='c:\T EMP' ):
dirs = [ ]
listing = os.listdir(dire ctory)
for x in listing:
x = os.path.join(di rectory, x)
print x
if os.path.isdir(x ):
dirs.append(x)
return dirs

[Fredrik Lundh]

Re: directory listing

Shi Mu wrote:
[color=blue]
> I tried this and no error reported but nothing appear on the console, why?
>
> import os
>
> def buildList( directory='c:\T EMP' ):
> dirs = [ ]
> listing = os.listdir(dire ctory)
> for x in listing:
> x = os.path.join(di rectory, x)
> print x
> if os.path.isdir(x ):
> dirs.append(x)
> return dirs[/color]

is that the entire script? you're defining a function, but you're
not calling it. try adding

print buildList()

at the end of the script.

</F>

[Shi Mu]

Re: directory listing

On 11/11/05, Fredrik Lundh <fredrik@python ware.com> wrote:[color=blue]
> Shi Mu wrote:
>[color=green]
> > I tried this and no error reported but nothing appear on the console, why?
> >
> > import os
> >
> > def buildList( directory='c:\T EMP' ):
> > dirs = [ ]
> > listing = os.listdir(dire ctory)
> > for x in listing:
> > x = os.path.join(di rectory, x)
> > print x
> > if os.path.isdir(x ):
> > dirs.append(x)
> > return dirs[/color]
>
> is that the entire script? you're defining a function, but you're
> not calling it. try adding
>
> print buildList()
>
> at the end of the script.[/color]

It works but i am curious why the line of "print x" does not show
anything. many thanks!

[Fredrik Lundh]

Re: directory listing

"Shi Mu" wrote:
[color=blue]
> but i am curious why the line of "print x" does not show
> anything.[/color]

because your c:\temp directory is empty ?

</F>

[Shi Mu]

Re: directory listing

On 11/11/05, Fredrik Lundh <fredrik@python ware.com> wrote:[color=blue]
> "Shi Mu" wrote:
>[color=green]
> > but i am curious why the line of "print x" does not show
> > anything.[/color]
>
> because your c:\temp directory is empty ?
>
> </F>[/color]
print buildList() gets lots of stuffs from my temp directory(there do
exist lots of files).
But why "print x' has nothing?

[Fredrik Lundh]

Re: directory listing

"Shi Mu" wrote:
[color=blue]
> print buildList() gets lots of stuffs from my temp directory(there do
> exist lots of files).
> But why "print x' has nothing?[/color]

C:\>more script.py
import os

def buildList( directory='c:\T EMP' ):
dirs = [ ]
listing = os.listdir(dire ctory)
for x in listing:
x = os.path.join(di rectory, x)
print x
if os.path.isdir(x ):
dirs.append(x)
return dirs

print buildList()

C:\>dir temp
....

2005-11-12 00:00 <KAT> .
2005-11-12 00:00 <KAT> ..
2005-11-12 00:00 20 bacon.dat
2005-11-12 00:00 <KAT> egg
2005-11-12 00:00 20 spam.txt
2 fil(er) 40 byte
3 katalog(er) 9 818 021 888 byte ledigt

C:\>python script.py
c:\TEMP\bacon.d at
c:\TEMP\egg
c:\TEMP\spam.tx t
['c:\\TEMP\\egg']

</F>

[Peter Hansen]

Re: directory listing

Shi Mu wrote:[color=blue]
> On 11/11/05, Fredrik Lundh <fredrik@python ware.com> wrote:[color=green]
>>Shi Mu wrote:[color=darkred]
>>>def buildList( directory='c:\T EMP' ):
>>> dirs = [ ]
>>> listing = os.listdir(dire ctory)
>>> for x in listing:
>>> x = os.path.join(di rectory, x)
>>> print x
>>> if os.path.isdir(x ):
>>> dirs.append(x)
>>> return dirs[/color][/color]
>
> It works but i am curious why the line of "print x" does not show
> anything. many thanks![/color]

Did you use directory='c:\T EMP' as shown above, or directory='c:\t emp' ?
If you used the lower case version, you are not really checking the
temp directory, since \t represents a TAB character. If that's the
case, try using a forward slash instead: c:/temp .

-Peter

[Michael Konrad]

Re: directory listing


This is what I decided on for a solution. I haven't tested it
cross-platform yet.

import os

def dirListing(dire ctory='/Users/mkonrad'):
"""Returns a list of directories."""
#variables
dirs = [] #list of directories

#list of directories and files
listing = os.listdir(dire ctory)

#get just the directories
for x in listing:
if os.path.isdir(d irectory+os.sep +x):
dirs.append(x)

return dirs

Fredrik Lundh wrote:[color=blue]
> "Shi Mu" wrote:
>[color=green]
>> print buildList() gets lots of stuffs from my temp directory(there do
>> exist lots of files).
>> But why "print x' has nothing?[/color]
>
> C:\>more script.py
> import os
>
> def buildList( directory='c:\T EMP' ):
> dirs = [ ]
> listing = os.listdir(dire ctory)
> for x in listing:
> x = os.path.join(di rectory, x)
> print x
> if os.path.isdir(x ):
> dirs.append(x)
> return dirs
>
> print buildList()
>
> C:\>dir temp
> ...
>
> 2005-11-12 00:00 <KAT> .
> 2005-11-12 00:00 <KAT> ..
> 2005-11-12 00:00 20 bacon.dat
> 2005-11-12 00:00 <KAT> egg
> 2005-11-12 00:00 20 spam.txt
> 2 fil(er) 40 byte
> 3 katalog(er) 9 818 021 888 byte ledigt
>
> C:\>python script.py
> c:\TEMP\bacon.d at
> c:\TEMP\egg
> c:\TEMP\spam.tx t
> ['c:\\TEMP\\egg']
>
> </F>
>
>
>[/color]