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1 Troubleshooting FileNotFoundError in Python | File Handling

Troubleshooting FileNotFoundError in Python | File Handling

In this comprehensive guide, I shared everything about FileNotFoundError. FileNotFoundError in Python is so common to raise but very necessary to understand. If you are a Python Coder and want to become a professional coder then must understand Python exceptions. In different cases and situations, you may get such exceptions, as mentioned in this post.

If you want to learn more, there is an additional resource shared here. let’s start to learn about the complete Python FileNotFoundError exception with examples.

Understand FileNotFoundError Exception in Python

File handling is a big subject in any programming language. In which we create or open a file to write something into that file to close. There are different operations you can perform on the files with Python programming. Sometimes we get FileNotFoundError due to some reasons, that you need to pay attention to.

FileNotFoundError means that the Python interpreter wants to open the file you requested that is not present at the same location you provided. Sometimes your file location is the same but the actual name of the file is incorrect. I want to give an example to explain everything.

Coding Example:

with open('nonexistent_file.txt', 'r') as file:
    content = file.read()

1 2	with open('nonexistent_file.txt', 'r') as file: content = file.read()

In this example, nonexistetn_file.txt is the name of the field that is not present in the same location in which your Python file has existed. When you execute this code you will get FileNotFoundError. What do you have to do? You have to read your code carefully and check the file whether is present in that location or not.

There are different cases you may face while working on your project and getting FileNotFoundError. just read it carefully to learn about such and avoid getting it again and again.

FileNotFoundError VS ImportError

These are the two common errors that are often raised when developers write some code about accessing different files or modules. Due to the not existing file, such an error was raised.

FileNotFoundError is related when you want to operate some operation like opening, reading writing, and closing the file that is not present at the location you want to access from. And ImportError exception raises no such module or incorrect module name you are trying to import.

Both errors need to be managed properly and show user-friendly messages to users. When you show user-friendly messages to manage errors it puts a positive impression on the user. And your users will be friendly and interact with your application.

try:
    import non_existent_module
except ImportError as e:
    print(f"Exception: {e}")

try:

import non_existent_module

except ImportError as e:

print(f"Exception: {e}")

In this example, the developer wants to import a module that is not installed in your system, In this situation you will get an ImportError exception that is different from the FileNotFoundError exception.

In this post, we have focused on FileNotFoundError in Python with different examples with this explanation.

In Different Cases you Get FileNotFoundError

These are the different cases or scenarios I want to share with you, in that situation, you may get FileNotFoundError. Every case is described in detail with possible examples.

Case 1: Open a Non-Existent Single File or Multiple Files

This is the case when you want to open a file that may be a single file or multiple you get such an error. Opening a file means creating a new file or creating a file you want to create. In some cases, if you want to create a file and want to avoid it from FileNotFoundError then you can use a different strategy. I want to give an example of when you are trying to open a new existed for different options.

Coding Example:

file_urls = ['myfile1.txt', 'myfile2.txt', 'myfile3.txt']
for file_url in file_urls:
    if os.path.exists(file_url):
        try:
            with open(file_url, 'r') as myfile:
                data = myfile.read()
            print(f"Content of '{file_url}': {data}")
        except FileNotFoundError:
            print(f"FileNotFoundError occurred while reading '{file_url}'.")
    else:
        print(f"The file '{file_url}' does not exist.")

file_urls = ['myfile1.txt', 'myfile2.txt', 'myfile3.txt']

for file_url in file_urls:

if os.path.exists(file_url):

try:

with open(file_url, 'r') as myfile:

data = myfile.read()

print(f"Content of '{file_url}': {data}")

except FileNotFoundError:

print(f"FileNotFoundError occurred while reading '{file_url}'.")

else:

print(f"The file '{file_url}' does not exist.")

This is the example reason for opening multiple fields that are not present in the location you are accessing. For single file opening, I have already discussed the example in the first article above. You can read that example.

Case 2. Delete a File That Doesn’t Exist

Another case is that, when you are working on a big project related to file handling, need to apply a delete operation on a file. In this situation, it may be a case when such a file is not present. And you get FileNotFoundError. So you need to check the existing path first. If that path is present at that location then delete the file otherwise a user-friendly error should display.

import os
os.remove('nonexistent_file.txt')

1 2	import os os.remove('nonexistent_file.txt')

In this case, you are about to delete a file with extension txt that does not exist, that is why you may get a file. so try to check its path to whether feil exists or not.

Case 4. Renaming a Non-Existent File

For example, you are working on your project, and need to rename any file to a new one. Some developers without checking their path, try to rename the file that is not present. The file may present but it may be an issue with your file, incorrect file name, incorrect directory name, etc.

# Attempting to rename a non-existent file
os.rename("nonexistent.txt", "newname.txt")

1 2	# Attempting to rename a non-existent file os.rename("nonexistent.txt", "newname.txt")

In this example, you are trying to rename any file using the os library rename method, but the file is not present, this is another case where you may get such an exception.

Case 6. Move a Non-Existent File

In this case, you may get FileNotFoundError when you want to move a file from one location to another location. In this case, you mentioned a folder name that is present but the file is not present. You get such an exception then.

import shutil
shutil.move("file_not_existed.txt", "folder/")

1 2	import shutil shutil.move("file_not_existed.txt", "folder/")

This is the shutil module in which the move method is working taking two parameters (file name and destination directory). Check the file and destination before moving.

Step-by-Step Troubleshooting FileNotFoundError

These are the step-by-step guide for you if you want to get a solution for FileNotFoundError you need to understand the following steps so you will get a solution.

After understanding these all steps, you have to apply them to your logic and code. When you fix your issue using the following steps, please mention in the comment which step helped you!

Step 01: Verify the File Path:

To avoid FileNotFoundError you need to double-check its path, whether such a path exists or not. Sometimes you are requesting a file that is not present in that location or you have deleted that path.

Step 02. Use Absolute Paths:

You can also use an absolute path rather than a relative path.
for example, there is a folder myproject -> test-> ali->exam.txt
In this case exam.txt file is present in ali fodler, ali folder is present in the test, test is in myproject.

Absolute path Example:

absolute_path = os.path.abspath("ali/exam.txt")

1	absolute_path = os.path.abspath("ali/exam.txt")

This path includes a complete URL, using abspath function, which includes its complete path.

Relative path Example:

relative_path = "ali/exam.txt"

1	relative_path = "ali/exam.txt"

In this example, you have to use just one folder name and file that is present in that folder. This ali folder will be in the location of the Python file.

Step 03. Check Current Working Directory:

os.getcwd() method used to check what is the current working directory. Current directory means in which are currently working. If you have to find a working directory it will become easy to find and verify the path of the current file.

Step 04. Verify File Existence Before Operations:

These are the methods os.path.exists() or Path.exists(), which you can use to verify at first before performing any operations on the file. File existence is very important to know because you cannot perform any operations without file existence.

Step 05. Inspect File Permissions:

You need to check before performing operations, have you permission to do this? If you have no permission to open a file, read writing, etc, you cannot do this.

Step 06. Handle Directory Existence:

Have you deleted the directory? Sometimes we delete the directory and try to access that directory. You have to check at first, whether that directory is present or not. If a directory is already present, still raising such an error, then come to the next step to find its solution.

Step 07. Check File Extension:

Extention is very important which tells the format and structure of a file. When you want to open a file you should mention the the correct name and its extension.

Extention is very important for any file. If you write an incorrect extension name, like txt to text. You will not get the expected output. Write the correct extension for the file.

Step 08. Review Code Logic:

Sometimes, each and everything is correct, but your logic is incorrect. Just read your code again, if it has a logical error, please debug that and then try it.

Step 09. Use Try-Except Blocks for File Operations:

This is the best practice for all levels of developers who check their code as a try if successfully run then no issue otherwise specific errors will be shown in the console. If you are using a try-except block for different performing operations. Because when you try your logic, if it fails to execute, you get an exception that will help you to find an actual error.

Step 10. Try Reading with Different Modes:

You should know that there are different modes of the operations, you are performing, which define the specific operations for a file. There are different modes (e.g., ‘r’, ‘rb’, ‘rt’) and methods you can use to read the file in different ways.

You need to change modes to read the file. Sometimes modes are not working, after checking modes like r or rt, you may solve this error.

Here is the complete table containing solutions for FileNotFoundError in Python:

Step Number	Solution	Example
Step 01	Verify the File Path	To avoid FileNotFoundError you need to double-check its path, whether such a path exists or not.
Step 02	Use Absolute Paths	absolute_path = os.path.abspath(“ali/exam.txt”)
Step 03	Check Current Working Directory	os.getcwd()
Step 04	Verify File Existence Before Operations	Use os.path.exists() or Path.exists() to verify the existence of the file before performing any operations.
Step 05	Inspect File Permissions	Check whether you have permission to perform the desired operations on the file.
Step 06	Handle Directory Existence	Ensure that the directory containing the file exists before attempting to access it.
Step 07	Check File Extension	Ensure that you provide the correct file extension when attempting to open or manipulate the file.
Step 08	Review Code Logic	Double-check the logic of your code to ensure that it correctly handles file operations.
Step 09	Use Try-Except Blocks for File Operations	Wrap file operations in try-except blocks to gracefully handle exceptions that may occur during execution.
Step 10	Try Reading with Different Modes	Experiment with different modes (‘r’, ‘rb’, ‘rt’) when reading files to determine the most appropriate mode for your needs.

Video Lecture for Fixing FileNotFoundError in Python

Here is the video for you guys, just watch it and try to understand, any feedback you can discuss it with me in the comment section.

Conclusion

These are the different strategies, for understanding FileNotFoundError in Python I have discussed. Different cases for example, in which you may get such an exception. There is an author’s recommendation mentioned here in the section on step-by-step debugging to find solutions for such exceptions.

Find file before fixing FileNotFoundError!

FAQ

What is FileNotFoundError in Python?

This is the error that arises when you want to open/read/write or any other operation want to perform that doesn’t exist. There are many different reasons why the file is not accessible to the interpreter, as already discussed.

When do I get such an error in Python code?

It is the time when you want to perform any operations on a file/folder etc, which does not exist or is no longer available in a specific location or directory.

Is there any proper solution or fixes for FileNotFoundError in Python?

Yes, there are different solutions to fix such errors for example Checking the Current Working Directory, Using Absolute Paths, Verifying the File Path, verifying file Existence Before Operations, Checking File Extension, etc.

Additional Resource

There are other exceptions also ValueError, ImportError, TabError, etc. You have to understand these executions in depth to manage them properly for users. I explain everything but if you want to learn more about other expectations I want to share additional resources for you.

Learn more about Python Exceptions

If you want to learn Complete Python with different concepts and examples, here is a guide for you. Python Tutorials!

Feedback & Comment

A comprehensive discussion about FileNotFoundError in Python with different examples and different cases and scenarios in which you get such errors. Everything concept is mentioned here in detail, what do you want to say now? Have you got your expectations from this article? Please mention your thoughts in the comment section.

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