Python os.path.join Method a step by step Guide

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Python os.path.join Method a step by step Guide
vinaykhatri

Vinay Khatri
Last updated on May 30, 2024

    os.path.join() is a method of os module in Python that can combine file or directory path names as a single path. This method is often used along with the other os modules method where we need to perform a joining path operation. The different operating system has different path system, so instead of writing the path structure manually, we use the os module path handling methods such as path.join() and do the task automatically.

    How to Use os.path.join() method in Python?

    Often working with files and directories in Python we come across the situation where we want to write a script that joins the file name with an absolute directory path. Although we can use the string concatenation operation to write the complete pathname, still when we want our program to run the same on any file path system, we use the inbuilt module like os which is compatible with all the popular operating systems that support Python.

    This Python guide will walk you through the os.path.join function that can combine a directory path with a file or directory name.

    What is a File Path?

    A file or directory path is a valid sequence of file or directory names that are located in a system. Different operating systems use different types of file systems, and to represent those file systems, they use different file path notations. For instance, the Windows operating system uses the backward slash "\" to represent the sequence of the file path.

    C:\Users\admin\Desktop\

    And operating systems, like Mac and Linux, use the forward-slash  "/" for file or directory paths.

    /Users/admin/videos/movie.mp4

    What is Python os.path.join?

    os is an inbuilt Python module that provides operating system functionalities to Python. As file management is a part of the operating system we can also use the os module to handle files using Python. With os.path.join function, we can combine the two or more pathnames to create a single file pathname. The path.join function does not create any new path instead, it just provides a name of the path by combining the specified path names.

    Syntax

    import os
    os.path.join(path1, path2)

    The path.join() method will join path1 with path2 as a single pathname.

    Example

    import os
    
    path1= r"C:\Users\admin\code"   #directory path
    path2 = r"index.html"   #file name
    
    full_path = os.path.join(path1, path2)
    
    print("The Full Path is:", full_path)
    Output
    The Full Path is: C:\Users\admin\code\index.html

    In the above example, I have represented path1 and path2 as a raw string, by putting the prefix r . This is because I am on a windows system, and windows use backslash "\"  as a directory separator for the file system.

    And in Python string, we use backslash as an escape character. And if we write the Windows file path as it is, the string will treat the directory separator backslash as an escape character and raise an error (SyntaxError: (unicode error) 'unicodeescape'), when the join method will try to join the path names. To represent the windows file path as a string, we should always consider using a raw string.

    Real use case of os.path.join() method

    In the above example, we hardcoded the name for both paths path1, and path2 . Using the path.join method in such a case does not make any sense. We could have also used string concatenation and joined both the pathname. The os.path.join() method really shines when it is used along with other os methods where we are getting the pathname dynamically, and we wish to name the complete path.

    Example

    Let's create a Python program that prints the absolute pathname for all the files and directories present in the current directory.

    import os
    
    # get the path for current directory
    current_dir = os.getcwd()
    
    # list the name of all the files and diretories
    all_files = os.listdir()
    
    for name in all_files:
    	# join the current directory path with file name
    	print(os.path.join(current_dir, name))

    Output

    D:\code\main.py
    D:\code\mousesimulate.py
    D:\code\movies.csv
    D:\code\msedgedriver.exe
    D:\code\music.mp3
    D:\code\my.pdf

    In the above example, first, we get the directory pathname for our current directory using the os.getcwd() method. Then we get the list of all the files that are present in our current directory using os.listdir() method. The os.listdir() method returns a list of all file and directory names present in the current directory. At last, we loop throw the all_files list and combine the name of all the files or directories present in the list with the current directory path using os.path.join() method.

    Conclusion

    The os.path.join function combines the name of two paths and return a string value of the complete pathname. With this method, we can easily combine two paths and create an absolute pathname. This method automatically adds a forward or backward slash between the specified path based on the operating system where the python program is running. This method come very useful when we are working with file management in python and want to list the complete or absolute path for the files or directories.

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