Make your way through our detailedPython exception handlingSeries we've arrived atImportError, along with its only child subclass ofModuleNotFoundError. Ö In this article, we examine the All Python exceptions inherit from Below is the complete code example that we will use in this article. It can be copied and pasted if you want to play around with the code and see how it all works. def principal(): se __name__ == "__main__": def principal(): se __name__ == "__main__": def principal(): se __name__ == "__main__": def principal(): se __name__ == "__main__": Class registration: @Class method :param args: Values to be output. @Class method :param value: Inserted text to be centered. # If no value is passed, the delimiter for the output length. # Circumferential insert with tabs. cls.__output(output) @Class method :param args: Values to be output. @Class method :param exception: A BaseException to throw. the apparently simple During Let's stick to the usual for our code examples def principal(): se __name__ == "__main__": Ö The general problem here is that the Alternatively, let's look at what happens when we move the def principal(): se __name__ == "__main__": Running this code - even with Python 2.7 - produces the same thing Ö def principal(): se __name__ == "__main__": We do that here too The cause of this error is exactly the same as in version 2.7, but it is more specific in 3.6+ def principal(): se __name__ == "__main__": With this code we can generate the Python version and handle the error: We also exhibit Air brake robusterror monitoringThe software provides real-time error monitoring and automatic exception reporting for all your development projects. Airbrake's state-of-the-art web dashboard ensures you receive 24/7 status updates on your application's health and error rates. No matter what you are working on, Airbrake easily integrates with all major languages and frameworks. In addition, Airbrake makes it easy to adjust exception parameters and gives you full control over the active error filtering system, so you only catch the most important errors. Try Airbrake's bug tracking software today and see for yourself why so many of the world's leading engineering teams are using Airbrake to revolutionize their exception handling techniques! Try Airbrake for free with a14 days free trial.ImportError
will be canceled if aimport
The statement has problems importing the specified module successfully. Usually this problem occurs due to an invalid or incorrect path generating anModuleNotFoundError
in Python 3.6 and newer.ImportError
eModuleNotFoundError
with a bit more detail starting with where they sit overallPython exception class hierarchy. We'll also look at some simple code examples that illustrate the differences inimport
Statement errors in newer (3.6) and older (2.7) versions of Python, so let's get started!the technical summary
BaseException
class or from a class inherited from it. The complete exception hierarchy for this error is:
BaseException
exception
ImportError
ModuleNotFoundError
Complete code sample
# outer_import_2.7.py
Import system
import gw_utility.Book
experiment:
print(sys.version)
except ImportError as error:
# Expected output from ImportErrors.
print(error.__class__.__name__ + ": " + error.message)
except exception as exception:
# Throw unexpected exceptions.
print(Exception, false)
print(Exception.__Class__.__Name__ + ": " + Exception.Message)
a director()# inner_import_2.7.py
Import system
experiment:
print(sys.version)
import gw_utility.Book
except ImportError as error:
# Expected output from ImportErrors.
print(error.__class__.__name__ + ": " + error.message)
except exception as exception:
# Throw unexpected exceptions.
print(Exception, false)
print(Exception.__Class__.__Name__ + ": " + Exception.Message)
a director()# outer_import_3.6.py
Import system
import gw_utility.Book
en gw_utility.logging import Logging
experiment:
logging.log (sys.version)
except ImportError as error:
# Expected output from ImportErrors.
Logging.log_exception (Error)
# Include the name and path attributes in the output.
Logging.log(f'error.name: {error.name}')
Logging.log(f'error.path: {error.path}')
except exception as exception:
# Throw unexpected exceptions.
Logging.log_exception(Exception, False)
a director()# inner_import_3.6.py
Import system
en gw_utility.logging import Logging
experiment:
logging.log (sys.version)
import gw_utility.Book
except ImportError as error:
# Expected output from ImportErrors.
Logging.log_exception (Error)
# Include the name and path attributes in the output.
Logging.log(f'error.name: {error.name}')
Logging.log(f'error.path: {error.path}')
except exception as exception:
# Throw unexpected exceptions.
Logging.log_exception(Exception, False)
a director()# log.py
Import math
Import system
Import tracking
separador_character_default = '-'
separador_length_default = 40
def __output(cls, *args, sep: str = ' ', end: str = '\n', file=None):
"""Prints the value(s) passed to the console.
:param sep: String inserted between values, a space by default.
:param end: String appended after the last value, default is a newline.
:param file: A file-like object (stream); the default is the current sys.stdout.
:back: None
"""
print(*args, set=set, end=end, file=file)
def line_separator(cls, Wert: str = None, Länge: int = separator_length_default,
char: str = separador_character_default):
"""Prints a line separator with the entered text centered in the middle.
:param length: Total length of the delimiter.
:param char: delimiter.
"""
output = value
if value == None oder len(value) == 0:
output = f'{characters * length}'
elif len(value) < length:
# Update the length based on the length of the insert minus a space for the margin.
length -= length(value) + 2
# Halve the length and bottom on the left.
left = math.floor(Länge / 2)
right = left
# If the number is odd, add the discarded remainder on the right.
if length % 2 != 0:
right += 1
output = f'{auto*left}{value}{character*right}'
def log(cls, *args, sep: str = ' ', end: str = '\n', file=None):
"""Prints the value(s) passed to the console.
:param sep: String inserted between values, a space by default.
:param end: String appended after the last value, default is a newline.
:param file: A file-like object (stream); the default is the current sys.stdout.
"""
cls.__output(*args, set=set, end=end, file=file)
def log_exception(cls, exception: BaseException, expected: bool = True):
"""Prints the BaseException passed to the console, including traceback.
:param expected: Determines whether BaseException was expected.
"""
output = "[{}] {}: {}".format('EXPECTED' se esperado senão 'UNEXPECTED', type(exception).__name__, exception)
cls.__output(output)
exc_type, exc_value, exc_traceback = sys.exc_info()
traceback.print_tb(exc_traceback)When should you use it?
import
The statement found in Python is actually quite complex when you look under the hood. At the most basic level, aimport
The statement is used to perform two tasks. It first tries to find the named module, loads and initializes it if necessary. It also automatically sets a name in the local namespace within the scope of the map.import
Explanation. This local name can then be used to refer to the called module in scoped code below.import
Instruction is the most commonly used technique to gain access to the code of other modules, Python offers others as wellmethods and functionsthat make up the built-in import system. Developers can use certain features to have finer control over the import process.import
Statement most of us are used to. As mentioned in the introduction, the behavior in the event of a failureIt is important
differs depending on the version of Python. To illustrate, let's start with theouter_import_2.7.py
Archive:# outer_import_2.7.py
Import system
import gw_utility.Book
experiment:
print(sys.version)
except ImportError as error:
# Expected output from ImportErrors.
print(error.__class__.__name__ + ": " + error.message)
except exception as exception:
# Throw unexpected exceptions.
print(Exception, false)
print(Exception.__Class__.__Name__ + ": " + Exception.Message)
a director()Outside
Prefix to filename indicates we are testing an "external" or global scopeimport
explanation ofgw_utility.Book
. Running this code produces the following output:Traceback (last most recent call):
Arquivo "C:\Users\Gabe\AppData\Local\JetBrains\Toolbox\apps\PyCharm-P\ch-0\172.3968.37\helpers\pydev\pydevd.py", linha 1599, in <module>
globals = debugger.run(setup['file'], None, None, is_module)
Arquivo "C:\Users\Gabe\AppData\Local\JetBrains\Toolbox\apps\PyCharm-P\ch-0\172.3968.37\helpers\pydev\pydevd.py", Zeile 1026, ausgeführt
pydev_imports.execfile(file, global, local) # Run the script
Arquivo "D:/work/Airbrake.io/Exceptions/Python/BaseException/Exception/ImportError/outer_import_2.7.py", Linha 3, in <module>
import gw_utility.Book
ImportError: No module named Bookgw_utility.Book
Module does not exist. Actually the correct modulelowercase letters:gw_utility.book
. Sinceimport
-Declaration is at the top of the file, it exists outside of oursTry - except
block, then dieImportError
we get in the log is not captured - execution stopped completely when the error was thrown.import
statement within aTry - except
block as seen ininner_import_2.7.py
:# inner_import_2.7.py
Import system
experiment:
print(sys.version)
import gw_utility.Book
except ImportError as error:
# Expected output from ImportErrors.
print(error.__class__.__name__ + ": " + error.message)
except exception as exception:
# Throw unexpected exceptions.
print(Exception, false)
print(Exception.__Class__.__Name__ + ": " + Exception.Message)
a director()ImportError
, but we can capture them and further process the capturedImportError
, if necessary:2.7.14 (v2.7.14:84471935ed, 16. September 2017, 20:25:58) [MSC v.1500 64 Bit (AMD64)]
ImportError: No module named BookModuleNotFoundError
was added in Python 3.6 as a subclass ofImportError
and an explicit reference to the same type of error that we saw in the 2.7 code above. For example, let's look at the exteriorimport
Example in Python 3.6 withouter_import_3.6.py
:# outer_import_3.6.py
Import system
import gw_utility.Book
en gw_utility.logging import Logging
experiment:
logging.log (sys.version)
except ImportError as error:
# Expected output from ImportErrors.
Logging.log_exception (Error)
# Include the name and path attributes in the output.
Logging.log(f'error.name: {error.name}')
Logging.log(f'error.path: {error.path}')
except exception as exception:
# Throw unexpected exceptions.
Logging.log_exception(Exception, False)
a director()import
the endTry - except
block, so running this code stops execution and produces the following output:Traceback (last most recent call):
Arquivo "C:\Users\Gabe\AppData\Local\JetBrains\Toolbox\apps\PyCharm-P\ch-0\172.3968.37\helpers\pydev\pydevd.py", linha 1599, in <module>
globals = debugger.run(setup['file'], None, None, is_module)
Arquivo "C:\Users\Gabe\AppData\Local\JetBrains\Toolbox\apps\PyCharm-P\ch-0\172.3968.37\helpers\pydev\pydevd.py", Zeile 1026, ausgeführt
pydev_imports.execfile(file, global, local) # Run the script
Arquivo "C:\Users\Gabe\AppData\Local\JetBrains\Toolbox\apps\PyCharm-P\ch-0\172.3968.37\helpers\pydev\_pydev_imps\_pydev_execfile.py", linha 18, kein arquivo exec
exec(compile(content+"\n", file, 'exec'), glob, loc)
Arquivo "D:/work/Airbrake.io/Exceptions/Python/BaseException/Exception/ImportError/outer_import_3.6.py", Linha 3, in <module>
import gw_utility.Book
ModuleNotFoundError: No module named "gw_utility.Book"ModuleNotFoundError
now it is time. Also, we can detect these errors when theimport
runs within aTry - except
Context:# inner_import_3.6.py
Import system
en gw_utility.logging import Logging
experiment:
logging.log (sys.version)
import gw_utility.Book
except ImportError as error:
# Expected output from ImportErrors.
Logging.log_exception (Error)
# Include the name and path attributes in the output.
Logging.log(f'error.name: {error.name}')
Logging.log(f'error.path: {error.path}')
except exception as exception:
# Throw unexpected exceptions.
Logging.log_exception(Exception, False)
a director()3.6.3 (v3.6.3:2c5fed8, 3.Oktober 2017, 18:11:49) [MSC v.1900 64 Bit (AMD64)]
[EXPECTED] ModuleNotFoundError: No module named "gw_utility.Book"
error.name: gw_utility.Book
error.path: NoneName
eAway
attributes ofImportError
object added in Python 3.3 to specify the name of the module that was attempted to be imported, along with the path to the file that threw the exception, if applicable. In this case, our code is fairly simple, so unfortunately none of the attributes are particularly useful.
Written by Frances Banks
FAQs
How do you fix ModuleNotFoundError and ImportError? ›
Python's ImportError ( ModuleNotFoundError ) indicates that you tried to import a module that Python doesn't find. It can usually be eliminated by adding a file named __init__.py to the directory and then adding this directory to $PYTHONPATH .
How do I fix the ImportError No module named error in Python? ›This can happen if you've misspelled the module name, or if you're trying to import a module that's not in your Python path. To fix this, make sure you're using the correct module name, and that the module is in your Python path (or at least in your project directory where you're executing your main . py file from.)
How do I fix ModuleNotFoundError in Python? ›...
How to fix the ModuleNotFoundError in Python
- Make sure imported modules are installed. Take for example, numpy . ...
- 2. Make sure modules are spelled correctly. ...
- 3. Make sure modules are in the right casing. ...
- 4. Make sure you use the right paths.
This error generally occurs when a class cannot be imported due to one of the following reasons: The imported class is in a circular dependency. The imported class is unavailable or was not created. The imported class name is misspelled. The imported class from a module is misplaced.
What is the difference between ImportError and ModuleNotFoundError? ›The ImportError is raised when an import statement has trouble successfully importing the specified module. Typically, such a problem is due to an invalid or incorrect path, which will raise a ModuleNotFoundError in Python 3.6 and newer versions.
Why can't i import Python module? ›This is caused by the fact that the version of Python you're running your script with is not configured to search for modules where you've installed them. This happens when you use the wrong installation of pip to install packages.
Why do I keep getting a no file exist error in Python? ›The Python FileNotFoundError: [Errno 2] No such file or directory error is often raised by the os library. This error tells you that you are trying to access a file or folder that does not exist. To fix this error, check that you are referring to the right file or folder in your program.
How do I resolve ImportError no module name? ›If you are facing python importerror: no module named error then to get rid of this error you just need to create __init__.py in the appropriate directory and everything will work fine.
How do you solve ImportError Cannot import name? ›- The Python "ImportError: cannot import name" often occurs when we have circular imports (importing members between the same files).
- To solve the error, move the functions or classes to a third file and import them from a central location in other files.
- Step 1) Create a file and name it test.py.
- Step 2) Inside test.py create a function called display_message() ...
- Step 3) Now create another file display.py.
- Step 4) Inside display.py import the moduletest.py file, as shown below: import test. ...
- Step5)
How do I fix Python path? ›
- Right click on My Computer and click on properties.
- Click on Advanced System settings.
- Click on Environment Variable tab.
- Click on new tab of user variables.
- Write path in variable name.
- Copy the path of Python folder.
- Paste path of Python in variable value. Click on Ok button: Click on Ok button:
If you have your own python files you want to import, you can use the import statement as follows: >>> import my_file # assuming you have the file, my_file.py in the current directory. # For files in other directories, provide path to that file, absolute or relative.
How does Python handle file exception? ›To handle the exception, we have put the code, result = numerator/denominator inside the try block. Now when an exception occurs, the rest of the code inside the try block is skipped. The except block catches the exception and statements inside the except block are executed.
How do I install all Python modules? ›- Install launcher for all users.
- Add Python to the PATH.
- Install pip (which allows Python to install other packages)
- Install tk/tcl and IDLE.
- Install the Python test suite.
- Install py launcher for all users.
- Associate files with Python.
- Create shortcuts for installed applications.
Make an empty file called __init__.py in the same directory as the files. That will signify to Python that it's "ok to import from this directory". The same holds true if the files are in a subdirectory - put an __init__.py in the subdirectory as well, and then use regular import statements, with dot notation.
What does __ init __ file do in Python? ›At its core, the __init__.py file is a file that is used to mark a directory as a Python package. Every directory that contains code that you want to be able to import as a simple Python package needs to contain an __init__.py. This includes subdirectories of directories that already have an __init__.py file in them.
What is the use of __ init __ py in Python? ›The __init__.py files are required to make Python treat directories containing the file as packages. This prevents directories with a common name, such as string , unintentionally hiding valid modules that occur later on the module search path.
How do I import a module from another directory in Python? ›The most Pythonic way to import a module from another folder is to place an empty file named __init__.py into that folder and use the relative path with the dot notation. For example, a module in the parent folder would be imported with from .. import module .
Why are imports so hard in Python? ›Imports are difficult because there are so many factors interacting with each other to make things work when they shouldn't, and make things fail/get a warning when they should not.
Can you manually import a module in Python? ›There are various methods that can be used to import the module by using its full path: Using sys. path. append() Function.
Why is it discouraged to import from a module Python? ›
Using import * in python programs is considered a bad habit because this way you are polluting your namespace, the import * statement imports all the functions and classes into your own namespace, which may clash with the functions you define or functions of other libraries that you import.
How do I check if an executable file exists in Python? ›To check if an existing file is executable, use os. access(path, mode), with the os. X_OK mode. Value to include in the mode parameter of access() to determine if path can be executed.
How do you get input in Python without getting EOF error? ›How EOFError can be overcome? We overcome this problem by using keywords like try() and except() in Python. This is referred to as Exception Handling.
How do I check if a file path exists in Python? ›How to Check if a File Exists Using the Path.is_file() Method in Python. The is_file() method checks if a file exists. It returns True if the Path object points to a file and False if the file doesn't exist. Since the example.txt file exists in the specified path, the is_file() method returns True .
How do I fix a cv2 error in Python? ›Regarding modulenotfounderror no module named cv2 This error may occur if you didn't install opencv module in your system. So first check this module is available or not. If it is not available, then install this module. But before that, try to check numpy module is available or not.
How do I resolve the unable to import module error that I receive when I run Lambda code in Python? ›This is because Lambda isn't prepackaged with all Python libraries. To resolve this, create a deployment package or Lambda layer that includes the libraries that you want to use in your Python code for Lambda. Important: Make sure that you put the library that you import for Python inside the /python folder.
Why is import cv2 not working? ›importerror no module named cv2 error occurs when cv2 module is not properly installed or its path is not properly set or configured. The straight-way fix for this error (no module named cv2) is to reinstall this module (OpenCV-python). In some scenario reinstalling this module automatically remove the older version.
How do I fix Importerror attempted relative import without known parent package? ›How to fix the "Importerror attempted relative import with no known parent package" error in Python? The solution to this problem is easy. Before advancing to the body of the Python program, programmers first create a Python file with their setup name; then make that package global so they can easily access it.
What error is caused by importing an unknown module Python? ›A ModuleNotFoundError is raised when Python cannot successfully import a module.
How do I fix name errors in Python? ›The NameError can be avoided by using a technique called Exception Handling. Even if we write code without any SyntaxError, the program can result in runtime errors. These are called Exceptions. There are numerous built-in exceptions available in Python, and One such exception is NameError Exception.
Which are the 3 different ways to import modules in Python? ›
- Using the import statement.
- Using from clause.
- Using from clause and *
- Import the whole module using its original name: import random.
- Import specific things from the module: from random import choice, randint.
- Import the whole module and rename it, usually using a shorter variable name: import pandas as pd.
- standard library imports (Python's built-in modules)
- related third party imports (modules that are installed and do not belong to the current application)
- local application imports (modules that belong to the current application)
An absolute path is also known as the full path and starts with / in Linux and macOS and C:/ on Windows. To find an absolute path in Python you import the os module then you can find the current working directory using os. path. abspath("insert-file-name-here") in your Python script.
How do I make a Python path executable? ›In the section entitled User Variables, double-click on the entry that says Path. Another window will pop up showing a list of paths. Click the New button and paste the path to your Python executable there. Once that's inserted, select your newly added path and click the Move Up button until it's at the top.
How do I manually add Python to path? ›- Right-clicking This PC and going to Properties.
- Clicking on the Advanced system settings in the menu on the left.
- Clicking on the Environment Variables button on the bottom right.
- In the System variables section, selecting the Path variable and clicking on Edit.
- Keep imports at the top of the file.
- Write imports on separate lines.
- Organize imports into groups: first standard library imports, then third-party imports, and finally local application or library imports.
- Order imports alphabetically within each group.
- Txt Files (.txt) import numpy as np. ...
- Csv Files (.csv) import pandas as pd. ...
- Pickle Files (.pkl) import picklewith open('data.pkl', 'rb') as file: ...
- Excel Files ( .xlsx ) import pandas as pdfile = 'datafile.xlsx' data = pd.ExcelFile(file)print(data.sheet_names)
When you import a module in Python, all the code in it will be run, and all the variables in that module will be stuck on that module object.
Do I need to import exception Python? ›The exceptions module provides the standard exception hierarchy. It's automatically imported when Python starts, and the exceptions are added to the _ _builtin_ _ module. In other words, you usually don't need to import this module.
What is the difference between exception handling and file handling? ›
June 22, 2021. Files are identified locations on a disk where associated data is stored. Working with files will make your programs fast when analyzing masses of data. Exceptions are special objects that any programming language uses to manage errors that occur when a program is running.
How exception is handled while opening file in Python? ›Handling Exceptions
Exceptions are handled with a “try – except” block. This provides another branching structure (kind of like if) – a way for different code to run depending on what happens in a code block. The try: block is code that you want to “try” to run. In this case, it's opening and processing a file.
- Open a command shell by typing 'powershell' in the Search Box of the Task bar.
- Enter: pip freeze | %{$_.split('==')[0]} | %{pip install --upgrade $_}
- Securely Download get-pip.py 1.
- Run python get-pip.py . 2 This will install or upgrade pip. Additionally, it will install setuptools and wheel if they're not installed already. Warning.
Use the pip install -r requirements.txt command to install all of the Python modules and packages listed in your requirements.txt file.
How do I import data from one file to another in Python? ›- Open the file1 , which has content in reading mode.
- Open the file2 in writing mode.
- Use for in loop to go through every line in file1 and write to file2 .
- Content is written to file2 .
- Close both the files.
- Open one file called test. txt in read mode.
- Open another file out. txt in write mode.
- Read each line from the input file and write it into the output file.
- Exit.
To run one Python file from another, you can use the exec function or the subprocess module. This will execute the code in other.py as if it were written in the main.py file.
How do you solve Importerror Cannot import name? ›- The Python "ImportError: cannot import name" often occurs when we have circular imports (importing members between the same files).
- To solve the error, move the functions or classes to a third file and import them from a central location in other files.
If you are facing python importerror: no module named error then to get rid of this error you just need to create __init__.py in the appropriate directory and everything will work fine.
How do you fix Importerror DLL load failed the specified module could not be found? ›
importerror: dll load failed: The specified module could not be found error occurs because of the incompatibilities of Microsoft Visual C++ (Visual Studio) versions. The best way to fix this error (importerror: dll load failed) is to reinstall/ install the Microsoft Visual C++ distribution.
How can I fix Importerror DLL load failed the specified module could not be found in Python 3? ›Reinstall Library. In most cases, the error occurs when you import a library. The cause of the error may be incorrect/incomplete installation or incompatibility of the library. In this case, you can try reinstalling the library to see whether the problem can be solved.
How do I import a local module into Python? ›- Definitions.
- Example.
- 1st solution: add root to sys.path.
- Relative import.
- 2nd solution: run as a module.
- Run as a module on Visual Code.
- 3rd solution : modify PYTHONPATH.
- 4rd solution (outdated): install in editable mode.
dll errors. If the User32. dll error message appeared during or after you installed a program, a hardware component, or a driver, uninstall the program, the hardware component, or the driver. Then restart Windows, and reinstall the program, the hardware component, or the driver.
How do I fix a missing DLL file? ›- Solution one: Re-install the software. ...
- Solution two: Run malware scanning. ...
- Solution three: Use system file checker. ...
- Solution four: Check for Windows Update. ...
- Solution five: System Restore.
- Restart your computer. ...
- Restore the deleted DLL file from the Recycle Bin. ...
- Recover the deleted DLL file with a free file recovery program. ...
- Run a virus/malware scan of your entire system. ...
- Use System Restore to undo recent system changes.
- Open an elevated command prompt.
- If the 32-bit DLL is in the %systemroot%\System32 folder, move it to the %systemroot%\SysWoW64 folder.
- Run the following command: %systemroot%\SysWoW64\regsvr32 <full path of the DLL>
This error has the following causes and solutions: The file isn't on the proper path. Ensure the DLL is on the Windows System path. The DLL is corrupted or was deleted.
Why am I getting file not found error in Python? ›The Python FileNotFoundError: [Errno 2] No such file or directory error is often raised by the os library. This error tells you that you are trying to access a file or folder that does not exist. To fix this error, check that you are referring to the right file or folder in your program.