# Learn Python Tips and Tricks Part 02

Hi friends! In this part we will learn how to get a list of files in a directory. How to rename the extensions of specific type of files. Imagine you have a directory of thousands files and you have to rename only a particular type of files. Manually doing such stuff would require lots of time and energy. But thanks to Python we can do this job quickly.

# Folder containing target files

We have a direction named all_files with some .json files in it.

banana.json
mango.json
orange.json
pear.json
apple.json


Our goal is to first find these .json files and then rename them as txt. Note that it is just an example and you can try with any kind of extensions.

## Using glob library to get paths of all files

Our small Python code will provide path of directory, and we use *.json in it to refer all json files in this path. So make try this simple code and use your own path accordingly.

### main.py

import os
import glob

path = 'all_files/*.json'
files = glob.glob(path)
print('Files found:',files)


Output:

python .\main.py
Files found: ['all_files\\apple.json', 'all_files\\banana.json', 'all_files\\mango.json', 'all_files\\orange.json', 'all_files\\pear.json']


We can see that glob.glob() has returned a list of paths of all json files.

## Iterate the list of files

We can use a simple for loop to iterate over files list. Get each file path and call it source src and destination dst.

### main.py

import os
import glob

path = 'all_files/*.json'
files = glob.glob(path)
print('Files found:',files)

for file in files:

src = file
dst = file.replace('.json','.txt')
print('src file:',src)
print('dst file:',dst)


Output:

python .\main.py
Files found: ['all_files\\apple.json', 'all_files\\banana.json', 'all_files\\mango.json', 'all_files\\orange.json', 'all_files\\pear.json']
src file: all_files\apple.json
dst file: all_files\apple.txt
src file: all_files\banana.json
dst file: all_files\banana.txt
src file: all_files\mango.json
dst file: all_files\mango.txt
src file: all_files\orange.json
dst file: all_files\orange.txt
src file: all_files\pear.json
dst file: all_files\pear.txt


## Perform the rename operation on files

We have the source and destination names, so lets us os library to rename them.

### main.py

import os
import glob

path = 'all_files/*.json'
files = glob.glob(path)
print('Files found:',files)

for file in files:

src = file
dst = file.replace('.json','.txt')
print('src file:',src)
print('dst file:',dst)
os.rename(src,dst)

path = 'all_files/*.txt'
files = glob.glob(path)
print('Files renamed:',files)


Output:

python .\main.py
Files found: ['all_files\\apple.json', 'all_files\\banana.json', 'all_files\\mango.json', 'all_files\\orange.json', 'all_files\\pear.json']
src file: all_files\apple.json
dst file: all_files\apple.txt
src file: all_files\banana.json
dst file: all_files\banana.txt
src file: all_files\mango.json
dst file: all_files\mango.txt
src file: all_files\orange.json
dst file: all_files\orange.txt
src file: all_files\pear.json
dst file: all_files\pear.txt
Files renamed: ['all_files\\apple.txt', 'all_files\\banana.txt', 'all_files\\mango.txt', 'all_files\\orange.txt', 'all_files\\pear.txt']


We can see that all files are renamed from .json to .txt. Of course we can do the reverse operation to find all .txt files and renamed them back to .json. But that is left as an excercise for you.

# Summary

In this tutorial we saw how to find all files with a particular extension in a directory or folder. How to rename all the files in it.