python - IOError: [Errno 2] No such file or directory trying to open a file

Question

I am very new to Python so please forgive the following basic code and problem, but I have been trying to figure out what is causing the error I am getting (I have even looked at similar threads on S.O.) but can't get past my issue.

Here is what I am trying to do:

• loop through a folder of CSV files
• search for a 'keyword' and delete all lines containing the 'keyword'
• save output to a separate folder

Here is my code:

import os, fnmatch
import shutil

src_dir = "C:/temp/CSV"
target_dir = "C:/temp/output2"
keyword = "KEYWORD"

for f in os.listdir(src_dir):
    os.path.join(src_dir, f)
    with open(f):
        for line in f:
            if keyword not in line:
                write(line)
                shutil.copy2(os.path.join(src_dir, f), target_dir)

Here is the error I am getting:

IOError: [Errno 2] No such file or directory: 'POS_03217_20120309_153244.csv'

I have confirmed that the folder and file do exist. What is causing the IOError and how to I resolve it? Also, is there anything else wrong with my code that would prevent me from performing the entire task?

Answer 1

Hmm, there are a few things going wrong here.

for f in os.listdir(src_dir):
    os.path.join(src_dir, f)

You're not storing the result of join. This should be something like:

for f in os.listdir(src_dir):
    f = os.path.join(src_dir, f)

This open call is is the cause of your IOError. (Because without storing the result of the join above, f was still just 'file.csv', not 'src_dir/file.csv'.)

Also, the syntax:

with open(f): 

is close, but the syntax isn't quite right. It should be with open(file_name) as file_object:. Then, you use to the file_object to perform read or write operations.

And finally:

write(line)

You told python what you wanted to write, but not where to write it. Write is a method on the file object. Try file_object.write(line).

Edit: You're also clobbering your input file. You probably want to open the output file and write lines to it as you're reading them in from the input file.

See: input / output in python.