Open all files in different directory python

Question

I need to open a file from a different directory without using it's path while staying in the current directory.

When I execute the below code:

for file in os.listdir(sub_dir):
    f = open(file, "r")
    lines = f.readlines()
    for line in lines:
        line.replace("dst=", ", ")
        line.replace("proto=", ", ")
        line.replace("dpt=", ", ")

I get the error message FileNotFoundError: [Errno 2] No such file or directory: because it's in a sub directory.

Question: Is there an os command I can use that will locate and open the file in sub_dir?

Thanks! -let me know if this is a repeat, I searched and couldn't find one but may have missed it.

you need to add the sub_dir path to your file in the open() function to be able to open it. — user1593705
– user1593705, Commented Aug 22, 2013 at 20:14

Martijn Pieters · Accepted Answer · 2013-08-22 20:28:08Z

13

os.listdir() lists only the filename without a path. Prepend these with sub_dir again:

for filename in os.listdir(sub_dir):
    f = open(os.path.join(sub_dir, filename), "r")

If all you are doing is loop over the lines from the file, just loop over the file itself; using with makes sure that the file is closed for you when done too. Last but not least, str.replace() returns the new string value, not change the value itself, so you need to store that return value:

for filename in os.listdir(sub_dir):
    with open(os.path.join(sub_dir, filename), "r") as f:
        for line in f:
            line = line.replace("dst=", ", ")
            line = line.replace("proto=", ", ")
            line = line.replace("dpt=", ", ")

edited Aug 22, 2013 at 20:28

answered Aug 22, 2013 at 20:13

Martijn Pieters

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5 Comments

hjames Over a year ago

If I wanted to write the new line to filename, would I add f.write(line) and open in a mode?

Martijn Pieters Over a year ago

@hjames: Sure, just adjust the mode parameter of the open() call.

hjames Over a year ago

Hmm, if I put it in a or w mode, it returns an error that the file isn't readable. If I put it in r mode it obviously can't write to the file.

hjames Over a year ago

io.UnsupportedOperation: not readable or io.UnsupportedOperation: not writable

Martijn Pieters Over a year ago

@hjames: Do you need to open the file for both reading and writing? Then use r+ or w+ (open existing file, r will leave existing data there, w will truncate existing files).

Saullo G. P. Castro · Accepted Answer · 2013-08-22 20:36:04Z

11

You must give the full path if those files are not in the current directory:

f = open( os.path.join(sub_dir, file) )

I would not use file as a variable name, maybe filename, since this is used to create a file object in Python.

edited Aug 22, 2013 at 20:36

answered Aug 22, 2013 at 20:14

Saullo G. P. Castro

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Comments

Rahul Telgote · Accepted Answer · 2017-03-28 16:38:33Z

-1

Code to copy files using shutil

import shutil
import os

source_dir = "D:\\StackOverFlow\\datasets"
dest_dir = "D:\\StackOverFlow\\test_datasets"
files = os.listdir("D:\\StackOverFlow\\datasets")

if not os.path.exists(dest_dir):
    os.makedirs(dest_dir)

for filename in files:
    if file.endswith(".txt"):
        shutil.copy(os.path.join(source_dir, filename), dest_dir)

print os.listdir(dest_dir)

edited Mar 28, 2017 at 16:38

answered Mar 28, 2017 at 13:47

Rahul Telgote

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