os.path.join but extract item of a list

Question

I want to do an os.path.join that contains a list in filenames because there are 3 files in that final folder. I want to only use the PST.shp

import os
fo = []
f = r'C:\Users\user\Desktop\folder\folder1'
for dirpath,dirnames,filenames in os.walk(f):      
        print(filenames)
        #fo.append(os.path.join(dirpath,filenames))

gives:

[]
[]
['PST.dbf', 'PST.shp', 'PST.shx']
[]
['PST.dbf', 'PST.shp', 'PST.shx']
[]
['PST.dbf', 'PST.shp', 'PST.shx']
[]
['PST.dbf', 'PST.shp', 'PST.shx']
[]

How to filter so I use only the PST.shp full path in the list fo?

something like:

 fo = []
    f = r'C:\Users\user\Desktop\folder\folder1'
    for dirpath,dirnames,filenames in os.walk(f):  
         if filenames not empty:    
            print(filenames)
            fo.append(os.path.join(dirpath,filenames[0][1]))

Check if `PST.shp` is in `filenames`. If yes `append` the path. ie, `fo.append(os.path.join(dirpath, 'PST.shp'))` — Abdul Niyas P M, Nov 19 '18 at 07:28
Since Python 3.5 `glob` is recursive so you could use that. See [Use a Glob() to find files recursively in Python?](https://stackoverflow.com/questions/2186525/use-a-glob-to-find-files-recursively-in-python) which also has pre-3.5 solutions. — Peter Wood, Nov 19 '18 at 07:32
See [**`fnmatch`**](https://docs.python.org/3/library/fnmatch.html). — Peter Wood, Nov 19 '18 at 07:34
ok this worked but is it possible to do it without referring to the name but use index? — user10671234, Nov 19 '18 at 07:39

Oli · Answer 1 · 2018-11-19T08:15:46.877

0

Use endswith function to check for extensiton as follows,

for dirpath,dirnames,filenames in os.walk(f):  
   for f in filenames:
       if f.endswith('.shp'):
          fo.append(os.path.join(dirpath,f))

edited Nov 19 '18 at 08:15

answered Nov 19 '18 at 07:37

Oli

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Serge Ballesta · Accepted Answer · 2018-11-19T13:27:29.317

If you are sure that you will only use the script to process a PST shape, just follow @AbdulNiyasPM's advice and check and process the PST.shp file:

     ...
     if filenames not empty:    
        print(filenames)
        if 'PST.shp' in filenames:
            fo.append(os.path.join(dirpath, 'PST.shp'))

If you want to keep any shp file, you can simple test that pattern:

     ...
     if filenames not empty:    
        print(filenames)
        for name in filenames:
            if name.endswith('.shp'):
                fo.append(os.path.join(dirpath, name))

Beware: if you need to be able to support non case sensitive platforms like Windows (ie: if you want to accept file names like xx.Shp or yy.SHP) a simple str.endswith is not enough, and you should use fnmatch or at least a non case sensitive regex (thanks to Peter Wood for his remark).

What if the filename is uppercase, `'PST.SHP'`? It would be safer to use [**`fnmatch`**](https://docs.python.org/3.1/library/fnmatch.html) as it deals with case based on operating system support. — Peter Wood, Nov 19 '18 at 08:35

os.path.join but extract item of a list

2 Answers2