Python Read All File Names in Directory

The Python os library is used to list the files in a directory. The Python os.listdir() method returns a list of every file and folder in a directory. os.walk() role returns a list of every file in an entire file tree.

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Oftentimes, when you're working with files in Python, yous'll encounter situations where you lot want to list the files in a directory. For example, you may want to discover all of the Python files in a folder.

The Python bone library offers a number of methods that can be used to list files in a directory. This tutorial will discuss how to use os.listdir() to go the files and folders in a director. We'll also talk about using os.walk() to get the files and folders in a directory and in its subdirectories.

Python os Library

The Python os library provides a number of functions that you can use to piece of work with operating systems. The functions included in the os module piece of work on whatever modern operating system, whether information technology is Windows, Linux, or Mac.

Since os is an external library, we need to import information technology into our code before we start using it. Nosotros tin exercise so using a Python import statement:

At present that we've imported the os library into our code, nosotros can get-go using its functions to listing items in a directory.

Python bone.listdir()

In Python, the os.listdir() method lists files and folders in a given directory. The method does non return special entries such every bit '.' and '..', which the operating system uses to navigate through different directories.

os.listdir() besides does not return files and folders beyond the first level of folders. In other words, os.listdir() does not render anything within subfolders discovered by the method.

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The os.listdir() role accepts one parameter: the file path of the directory whose file and folder names you want to retrieve.

Hither's the syntax for the listdir method:

Let's walk through an instance to showcase how to utilize this method in a Python program.

os.listdir() Python Example

Say that we are creating a program that analyzes the stock market performance of Netflix over the terminal decade. Nosotros take a folder (proper name: /dwelling house/data_analysis/netflix) with all of our raw data, and before our programme starts running, we want to check to make sure that the file raw_data_2019.csv exists within that binder.

In guild to part properly, our program needs that particular file to exist stored in that particular folder.

We could use the following lawmaking to retrieve a list of the files in the /home/data_analysis/netflix piece of work directory:

import os  path = '/home/data_analysis/netflix'  files = os.listdir(path)  for f in files: 	impress(f)          

Our program retrieves a list of all files and folders in the specified directory and returns the following:

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README.dr. app.py raw_data_2016.csv raw_data_2017.csv raw_data_2018.csv raw_data_2019.csv processed_data          

Now, we can bank check to see if the file raw_data_2019.csv is in the folder. As you tin can see, it is.

Permit'due south break down our code. On the start line, we import the os module, which nosotros need to do in lodge to admission the bone.listdir() part. Then, we declare a Python variable called path, which stores the name of the path whose contents we want to recall.

On the next line, we use the os.listdir() method to become a list of the files and folders in the /domicile/data_analysis/netflix directory. Finally, we create a Python for loop. This loop iterates through every item in the list produced by os.listdir(). We impress out the proper name of each file to the console using a Python print() argument.

The /home/data_analysis/netflix directory contained vi files and 1 directory. The directory is chosen processed_data and is distinguishable from the other files because it does non have an extension.

Python os.walk()

The os.walk() function retrieves a list of files contained inside a tree. The method iterates over each directory in a tree. Then, os.walk() returns the name of every file and folder within a directory and any of its subdirectories.

The syntax for the os.walk() method is every bit follows:

os.walk(top, topdown, onerror, followlinks)

The os.walk() method accepts four parameters:

• peak is the top directory whose component file and binder names you want to recollect (required)
• topdown, when set to True, specifies that directories should be scanned from the top downward. If this value is set to False, directories will be scanned from the lesser up (optional)
• onerror provides an error handler if an error is encountered (optional)
• followlinks, if set to Truthful, visits folders referenced by system links (optional)

We are going to focus on the first two parameters since onerror and followlinks are more advanced and are non as ordinarily used.

os.walk() Python Instance

Let's say that we want to retrieve the names of all files in the /home/data_analysis/netflix directory. Nosotros also want to find out what's enclosed within all subdirectories in that folder.

Equally nosotros discussed above, the netflix directory contains 1 binder: processed_data. We could apply the following code to call back the names of all files in the /dwelling house/data_analysis/netflix directory and its subdirectories:

import bone  path = '/dwelling/data_analysis/netflix'  for root, directories, files in os.walk(path, topdown=False): 	for name in files: 		print(os.path.bring together(root, proper name)) 	for proper noun in directories: 		print(bone.path.join(root, name))          

Here's the output from our code:

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/home/data_analysis/netflix/README.md /home/data_analysis/netflix/app.py /home/data_analysis/netflix/raw_data_2016.csv /home/data_analysis/netflix/raw_data_2017.csv /home/data_analysis/netflix/raw_data_2018.csv /home/data_analysis/netflix/raw_data_2019.csv /home/data_analysis/netflix/processed_data /home/data_analysis/netflix/processed_data/final.csv          

Nosotros import the bone module from which nosotros reference the bone.walk() and os.path.join() methods later in our code. Then, nosotros declare a variable called path, which stores the path whose file names we want to notice.

We then create a for loop that uses os.walk() to retrieve a listing of all files and folders in the path directory. That loop iterates through the files and folders that os.walk() returns. It'southward worth noting that we specify the topdown=False parameter in the os.walk() method, which tells our code to behave a peak-down search.

Our for loop iterates through each file and directory discovered by the os.walk() method using additional for loops. We impress out the files in os.walk() to the console.

In our code to a higher place, here are our for loops:

for root, directories, files in os.walk(path): 	for proper name in files: 		impress(os.path.bring together(root, name)) 	for name in directories: 		print(os.path.join(root, proper name))

Then, our plan uses os.path.bring together() to join together the root folder of each file (i.e. /abode/data_analysis/netflix)and the name of the file (i.e. raw_datra_2019.csv). The root binder refers to the directory path in which a file exists.

Conclusion

You tin use the Python listdir() method to do this. You can also use the walk() method, which lists everything in a directory, including anything within subdirectories.

This guide explored, providing examples, how to use the os.listdir() and os.walk() methods to list files and folders in a directory in Python. Now you lot have the skills you need to list files in a directory in Python like an expert!

To larn more about coding in Python, read our full How to Learn Python guide.

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Source: https://careerkarma.com/blog/python-list-files-in-directory/

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