Logo Questions Linux Laravel Mysql Ubuntu Git Menu
 

Do I need to pass the full path of a file in another directory to open()?

I have a folder with ten files in it which I want to loop through. When I print out the name of the file my code works fine:

import os
indir = '/home/des/test'
for root, dirs, filenames in os.walk(indir):
    for f in filenames:
        print(f)

Which prints:

1
2
3
4
5
6
7
8
9
10

But if I try to open the file in the loop I get an IO error:

import os
indir = '/home/des/test'
for root, dirs, filenames in os.walk(indir):
    for f in filenames:
        log = open(f, 'r')

Traceback (most recent call last):
File "/home/des/my_python_progs/loop_over_dir.py", line 6, in <module>
log = open(f, 'r')
IOError: [Errno 2] No such file or directory: '1'
>>> 

Do I need to pass the full path of the file even inside the loop to open() them?

like image 635
balcoder Avatar asked Aug 03 '12 18:08

balcoder


People also ask

What is it called when you use the complete path to a file or directory?

An absolute path refers to the complete details needed to locate a file or folder, starting from the root element and ending with the other subdirectories. Absolute paths are used in websites and operating systems for locating files and folders. An absolute path is also known as an absolute pathname or full path.

What is a full file path?

A full path is also referred to as the file path or the absolute path and refers to the location of your web site files on the server, relative to the server's file system structure.

Does full path include filename?

Paths include the root, the filename, or both. That is, paths can be formed by adding either the root, filename, or both, to a directory.


4 Answers

Yes, you need the full path.

log = open(os.path.join(root, f), 'r')

Is the quick fix. As the comment pointed out, os.walk decends into subdirs so you do need to use the current directory root rather than indir as the base for the path join.

like image 28
koblas Avatar answered Oct 21 '22 20:10

koblas


If you are just looking for the files in a single directory (ie you are not trying to traverse a directory tree, which it doesn't look like), why not simply use os.listdir():

import os  
for fn in os.listdir('.'):
     if os.path.isfile(fn):
        print (fn)

in place of os.walk(). You can specify a directory path as a parameter for os.listdir(). os.path.isfile() will determine if the given filename is for a file.

like image 193
Levon Avatar answered Oct 21 '22 22:10

Levon


You have to specify the path that you are working on:

source = '/home/test/py_test/'
for root, dirs, filenames in os.walk(source):
    for f in filenames:
        print f
        fullpath = os.path.join(source, f)
        log = open(fullpath, 'r')
like image 27
Mustafa Avatar answered Oct 21 '22 21:10

Mustafa


The examples to os.walk in the documentation show how to do this:

for root, dirs, filenames in os.walk(indir):
    for f in filenames:
        log = open(os.path.join(root, f),'r')

How did you expect the "open" function to know that the string "1" is supposed to mean "/home/des/test/1" (unless "/home/des/test" happens to be your current working directory)?

like image 29
abarnert Avatar answered Oct 21 '22 22:10

abarnert