Javascript List File In The Example Directory
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Michael Zippo
04.11.2021
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The Python operating system library is used to list files in a directory. The Python os.listdir () method returns a list of all files and folders in a directory. The os.walk () function returns a list of all files in an entire file tree.
Often when working with files in Python, you will come across situations where you want to list files in a directory. For example, you might want to find all of the Python files in one folder.
The Python OS library provides a number of methods that can be used to list files in a directory. This tutorial will explain how to use os.listdir () to get files and folders in a director. We’ll also talk about using os.walk () to get 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 work with operating systems. The functions included in the os module work on any modern operating system, be it Windows, Linux or Mac.
Since os is an external library, we need to import it into our code before we start using it. We can do this using a Python import statement :
Now that we have imported the os library into our code, we can start using its functions to list the items in a directory.
Python os.listdir ()
In Python, the os.listdir () method lists files and folders in a given directory. The method does not return special entries such as ’.’ and ’..’, which the operating system uses to navigate between different directories.
os.listdir () also does not return files and folders beyond the first level of folders. In other words, os.listdir () does not return anything in the subfolders discovered by the method.
The os.listdir () function takes one parameter: the file path of the directory whose file and folder names you want to retrieve.
Here is the syntax of the listdir method:
Let’s do an example to show how to use this method in a Python program.
os.listdir () Python example
Let’s say we create a program that analyzes the Netflix stock market trend over the past We have a folder (name: / home / data_analysis / netflix) with all of our raw data and, before our program starts, we want to verify that the raw_data_2019.csv file exists inside that folder.
To function correctly, our program needs m emorizing that particular file in that particular folder.
We could use the following code to retrieve a list of files in the working directory / home / data_analysis / netflix:
Our program retrieves a list of all files and folders in the specified directory and returns the following:
We can now check if the file raw_data_2019.csv is on file. As you can see, it is.
Let’s break down our code. In the first line we import the os module, which we need to do to access the os.listdir () function. Next, we declare a Python variable called path, which stores the name of the path whose contents we want to retrieve.
On the next line, we use the os.listdir () method to get a list of files and folders in the / home / data_analysis / netflix directory. Finally, let’s create a Python for loop . This loop iterates through each element of the list produced by os.listdir (). We print the name of each file to the console using a ’ Python print () statement .
The / home / data_analysis / netflix directory contained six files and one directory. The directory is called processor_data and is distinguished from other files because it has no extension.
Python os.walk ()
The os.walk () function retrieves a list of files contained in a tree. The method traverses each directory of a tree structure. Next, os.walk () returns the name of each file and folder in a directory and one of its subdirectories.
The syntax of os.walk () is as follows:
The os.walk () method accepts four parameters:
- top is the root directory where you want to run component file and folder names ettrieve (required)
- topdown , when set to True, specifies that directories should be crawled top to bottom. If this value is set to False, directories will be scanned from bottom to top (optional)
- onerror provides an error handler if an error occurs (optional)
- followlinks , if set to True, visit folders referenced by system links (optional)
We will focus on the first two parameters since onerror and followlinks are more advanced and not commonly used.
Python os.walk () example
Let’s say we want to get the names of all the files in the file / home / data_analysis / netflix. We also want to know what is included in all the subdirectories of this folder.
As noted above, the netflix directory contains a folder: processor_data. We could use the following code to retrieve the names of all the files in the directory of the / home / data_analysis / netflix and subdirectories:
Here is the output of our code:
We import the os module from which we refer to os.walk () and os .path.join () later in our code. Next, we declare a variable called path, which stores the path whose filenames we want to know.
Next, we create a for loop that uses os.walk () to retrieve a list of all files and folders in the path directory. This loop cycles through the files and folders returned by os.walk (). Note that we specify the topdown = False parameter in the os.walk () method, which tells our code to search from top to bottom.
Our for loop iterates through every file and directory discovered by the os.walk () method using additional for loops. We print the files to os.walk () on the console.
In our code above, here are our for the loop:
Then our program uses os.path.join () to merge the root folder of each file (ie / home / data_analysis / netflix) and the file name (ie raw_datra_2019.csv). The root folder refers to the path to the directory where a file exists.
Conclusion
You can use the Python listdir () method to do this. You can also use the walk () method, which lists everything in a directory, including everything in subdirectories.
This guide has explored, providing examples, how to use the os.listdir () and os.walk () methods to list files and folders in a directory in Python. You now have the skills to list files in a directory in Python like an expert!
To learn more about coding in Python, read our Python Learning Guide .
👻 Read also: what is the best laptop for engineering students?
We hope this article has helped you to resolve the problem. Apart from Javascript List File In The Example Directory, check other ast Python module-related topics.
Want to excel in Python? See our review of the best Python online courses 2023. If you are interested in Data Science, check also how to learn programming in R.
By the way, this material is also available in other languages:
Angelo Robinson
Shanghai | 2023-01-27
re Python module is always a bit confusing 😭 Javascript List File In The Example Directory is not the only problem I encountered. Will get back tomorrow with feedback
Oliver Porretti
Warsaw | 2023-01-27
Thanks for explaining! I was stuck with Javascript List File In The Example Directory for some hours, finally got it done 🤗. I just hope that will not emerge anymore
Carlo Chamberlet
London | 2023-01-27
I was preparing for my coding interview, thanks for clarifying this - Javascript List File In The Example Directory in Python is not the simplest one. Will use it in my bachelor thesis
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