How to change multiple filenames in a directory using Python

Question

I am learning Python and I have been tasked with:

adding "file_" to the beginning of each name in a directory
changing the extension (directory contains 4 different types currently: .py, .TEXT, .rtf, .text)

I have many files, all with different names, each 7 characters long. I was able to change the extensions but it feels very clunky. I am positive there is a cleaner way to write the following (but its functioning, so no complaints on that note):

    import os, sys
    path = 'C:/Users/dana/Desktop/text_files_2/'
        for filename in os.listdir(path):
            if filename.endswith('.rtf'):
                newname = filename.replace('.rtf', '.txt')
                os.rename(filename, newname)
        elif filename.endswith('.py'):
                newname = filename.replace('.py', '.txt')
                os.rename(filename, newname)
        elif filename.endswith('.TEXT'):
                newname = filename.replace('.TEXT', '.txt')
                os.rename(filename, newname)
        elif filename.endswith('.text'):
               newname = filename.replace('.text', '.txt')
               os.rename(filename, newname)

I do still have a bit of a problem:

the script currently must be inside my directory for it to run.
I can not figure out how to add "file_" to the start of each of the filenames [you would think that would be the easy part]. I have tried declaring newname as
```
newname = 'file_' + str(filename)
```
it then states filename is undefined.

Any assistance on my two existing issues would be greatly appreciated.

newname = 'file_' + filename should work. You don't need the str() because filename refers to a string already, but even so that should have worked. Maybe you tried it outside the loop? — cdarke
– cdarke, Commented Jan 23, 2016 at 6:34
One other comment: please be careful of indentation when posting code. You know that it is critical in Python. The code shown, for example, will not compile as it is. — cdarke
– cdarke, Commented Jan 23, 2016 at 8:18

realhu · Accepted Answer · 2016-01-23 07:10:35Z

5

The basic idea would be first get the file extension part and the real file name part, then put the filename into a new string.

os.path.splitext(p) method will help to get the file extensions, for example: os.path.splitext('hello.world.aaa.txt') will return ['hello.world.aaa', '.txt'], it will ignore the leading dots.

So in this case, it can be done like this:

import os
import sys

path = 'C:/Users/dana/Desktop/text_files_2/'

for filename in os.listdir(path):
    filename_splitext = os.path.splitext(filename)
    if filename_splitext[1] in ['.rtf', '.py', '.TEXT', '.text']:
        os.rename(os.path.join(path, filename), 
                os.path.join(path, 'file_' + filename_splitext[0] +  '.txt'))

edited Jan 23, 2016 at 7:10

answered Jan 23, 2016 at 7:03

realhu

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Comments

Mike Müller · Accepted Answer · 2016-01-23 06:48:07Z

3

Supply the full path name with os.path.join():

os.rename(os.path.join(path, filename), os.path.join(name, newname))

and you can run your program from any directory.

You can further simply your program:

extensions = ['.rtf', '.py', '.TEXT', '.text']
for extension in extensions:
     if filename.endswith(extension):
         newname = filename.replace(extension, '.txt')
         os.rename(os.path.join(path, filename), os.path.join(path, newname))
         break

All the other elif statements are not needed anymore.

edited Jan 23, 2016 at 6:48

answered Jan 23, 2016 at 6:31

Mike Müller

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4 Comments

Dana Scott Over a year ago

Tried this and name is then undefined.

Dana Scott Over a year ago

Much simpler to declare those extensions. -thank you for the suggestion.

Dana Scott Over a year ago

Traceback (most recent call last): File "C:/Users/dana/Desktop/scott_suffix_change2.py", line 16, in <module> os.rename(os.path.join(path, filename), os.path.join(name, newname)) NameError: name 'name' is not defined

Mike Müller Over a year ago

Sorry. Typo. Updated my answer. Not name but path.

irakli khitarishvili · Accepted Answer · 2016-01-23 07:32:32Z

import glob, os

path = 'test/'# your path
extensions = ['.rtf', '.py', '.TEXT', '.text']
for file in glob.glob(os.path.join(path, '*.*')):
    file_path, extension = os.path.splitext(file)
    if extension in extensions:
        new_file_name = '{0}.txt'.format(
            os.path.basename(file_path)
        )
    if not new_file_name.startswith('file_'): # check if file allready has 'file_' at beginning
        new_file_name = 'file_{0}'.format( # if not add 
                new_file_name
        )

    new_file = os.path.join(
            os.path.dirname(file_path),
            new_file_name
    )

    os.rename(file, new_file)

file_path, extension = os.path.splitext(file) getting file path without extension and extension f.e ('dir_name/file_name_without_extension','.extension')
os.path.dirname(file_path) getting directory f.e if file_path is dir1/dir2/file.ext result will be 'dir1/dir2'
os.path.basename(file_path) getting file name without extension

Bhagat Janarthanan · Accepted Answer · 2016-01-23 06:46:49Z

0

import os, sys
path = 'data' // Initial path

def changeFileName( path, oldExtensions, newExtension ):
    for name in os.listdir(path):
        for oldExtension in oldExtensions:
            if name.endswith(oldExtension):
                name = os.path.join(path, name)
                newName = name.replace(oldExtension, newExtension)
                os.rename(name, newName)
                break;

if __name__ == "__main__":
    changeFileName( 'data', ['.py', '.rtf' , '.text', '.TEXT'], '.txt')

Use an array to store all the old extensions and iterate through them.

answered Jan 23, 2016 at 6:46

Bhagat Janarthanan

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1 Comment

Dana Scott Over a year ago

That is an interesting approach and very informative. Thank you.

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