TechBeamersTechBeamers
  • Learn ProgrammingLearn Programming
    • Python Programming
      • Python Basic
      • Python OOP
      • Python Pandas
      • Python PIP
      • Python Advanced
      • Python Selenium
    • Python Examples
    • Selenium Tutorials
      • Selenium with Java
      • Selenium with Python
    • Software Testing Tutorials
    • Java Programming
      • Java Basic
      • Java Flow Control
      • Java OOP
    • C Programming
    • Linux Commands
    • MySQL Commands
    • Agile in Software
    • AngularJS Guides
    • Android Tutorials
  • Interview PrepInterview Prep
    • SQL Interview Questions
    • Testing Interview Q&A
    • Python Interview Q&A
    • Selenium Interview Q&A
    • C Sharp Interview Q&A
    • PHP Interview Questions
    • Java Interview Questions
    • Web Development Q&A
  • Self AssessmentSelf Assessment
    • Python Test
    • Java Online Test
    • Selenium Quiz
    • Testing Quiz
    • HTML CSS Quiz
    • Shell Script Test
    • C/C++ Coding Test
Search
  • Python Multiline String
  • Python Multiline Comment
  • Python Iterate String
  • Python Dictionary
  • Python Lists
  • Python List Contains
  • Page Object Model
  • TestNG Annotations
  • Python Function Quiz
  • Python String Quiz
  • Python OOP Test
  • Java Spring Test
  • Java Collection Quiz
  • JavaScript Skill Test
  • Selenium Skill Test
  • Selenium Python Quiz
  • Shell Scripting Test
  • Latest Python Q&A
  • CSharp Coding Q&A
  • SQL Query Question
  • Top Selenium Q&A
  • Top QA Questions
  • Latest Testing Q&A
  • REST API Questions
  • Linux Interview Q&A
  • Shell Script Questions
© 2024 TechBeamers. All Rights Reserved.
Reading: How to Use Pylint in Python
Font ResizerAa
TechBeamersTechBeamers
Font ResizerAa
  • Python
  • SQL
  • C
  • Java
  • Testing
  • Selenium
  • Agile Concepts Simplified
  • Linux
  • MySQL
  • Python Quizzes
  • Java Quiz
  • Testing Quiz
  • Shell Script Quiz
  • WebDev Interview
  • Python Basic
  • Python Examples
  • Python Advanced
  • Python OOP
  • Python Selenium
  • General Tech
Search
  • Programming Tutorials
    • Python Tutorial
    • Python Examples
    • Java Tutorial
    • C Tutorial
    • MySQL Tutorial
    • Selenium Tutorial
    • Testing Tutorial
  • Top Interview Q&A
    • SQL Interview
    • Web Dev Interview
  • Best Coding Quiz
    • Python Quizzes
    • Java Quiz
    • Testing Quiz
    • ShellScript Quiz
Follow US
© 2024 TechBeamers. All Rights Reserved.
Python AdvancedPython Tutorials

How to Use Pylint in Python

Last updated: May 02, 2024 10:51 pm
By Meenakshi Agarwal
Share
8 Min Read
Pylint Tool Usage
SHARE

From this tutorial, you will be learning to use and run Pylint for Python files. It is a static code analysis tool to find coding errors in your Python code.

Contents
What is Pylint?How to install Pylint?How to use and run?Run Pylint for a single fileRun on multiple filesRun on a directoryAnalyze files concurrentlyDefine output formatUsing .pylintrc configRun Pylint with examplesSample program with style issuesRun pylintFix errors and re-runPython Functions Quiz – A Refresher

Understanding Pylint

Pylint is an essential tool for Python programmers. Initially, it was created to focus on styling checks. However, later it brought more checks and features to detect style and logical issues.

The creator of Pylint namely Sylvain Thénault derived its name from the Unix tool lint. It too analyzes source code for potential errors. Hence, Thénault wanted to create a similar utility specifically for Python.

Note: The syntax used in the below section is for Python 3. You may change it to use a different version of Python.

Find the Best Python IDE for Programming

Check out the 10 best IDEs for Python programming. Choose the one that helps you code faster while making testing and debugging easier.

Top 10Watch

What is Pylint?

It is a static code analysis tool to identify errors in Python code and helps programmers enforce good coding styles. This tool enables them to debug complex code with less manual work.

It is one of the tools that gets used for test-driven development (TDD). The coding style that Pylint applies to the code is known as PEP8.

For more information, about PEP8 visit the link: PEP8 Style Guide for Python

Other products which are similar to Pylint are Pyflakes, Mypy, etc. It is a must-have tool for every beginner as well as advanced users. It scans and rates programs with a score according to the rules outlined in the PEP8 style guide.

How to install Pylint?

To install it on systems such as Windows 10, Mac OS, and Linux, use the following command:

pip install pylint

You can also use alternative methods such as:

1. On Debian, Kali Linux, and Ubuntu-based systems such as Ubuntu, Elementary, etc.

# Debian, Kali Linux, Ubuntu
sudo apt install pylint

2. On Fedora

# Fedora
sudo dnf install pylint

3. On OpenSUSE

# OpenSUSE
sudo zypper install pylint

or

# OpenSUSE
sudo zypper install python3-pylint

You can even integrate Pylint into various IDE (Integrated Development Environment) such as Eclipse, Visual Studio Code, etc. However, here, we will focus on Pylint usage without using IDE integration.

How to use and run?

To run Pylint, use the command line and specify its name as the command. It can be run in many cases like run on a single or multiple files or even a directory.

Run Pylint for a single file

The command to use Pylint on a Python file is:

# Check for style errors
pylint filename.py

It returns output consisting of semantic errors, syntax errors, errors in coding style, bugs in the code, excessive and redundant code, etc. It also assigns a score that indicates whether the Python code is an ideal one to use and maintains a history of scores obtained while running over a Python file as well as after each edit.

Run on multiple files

You can type multiple Python files separated by spaces after the Pylint command. It processes each file sequentially, scanning them one by one. So, it will analyze each Python file in the order they are provided.

This is the default Pylint command to run on multiple files in the default sequential way.

pylint task1.py task2.py task3.py

Run on a directory

To run Pylint on a directory, use the following command. It will analyze all the Python files inside the dir and subdirectories.

pylint code_dir/

Analyze files concurrently

Pylint provides a way to scan multiple files in parallel to speed up the process.

You can run Pylint for multiple files concurrently using the following command.

pylint --jobs=4 task1.py task2.py task3.py task4.py

Simultaneously, the same can be done for the files in a directory.

pylint --jobs=4 code_dir/

In both cases, the –jobs option controls the number of parallel jobs Pylint will run for analysis.

Define output format

When you run Pylint, it prints the results in plain text on the console. However, it accepts various output formats. For example, follow the below command.

pylint --output-format=json task1.py

Using .pylintrc config

To use the consistent coding standard across projects or teams, you must use the .pylintrc file. When you run Pylint, it looks for a configuration file named .pylintrc in the current working directory. It reads the settings from it and applies them during the analysis of Python files.

Here is a .pylintrc file incorporating the most common options you should configure.

[MASTER]

# Specify the maximum line length
max-line-length = 100

# Specify the output format (default is text)
output-format = colorized

# Specify additional paths to look for modules
init-hook='import sys; sys.path.append("path/to/your/modules")'

# Set the default score threshold for generating a report (0 to disable)
evaluation = 10.0

[MESSAGES CONTROL]

# Disable certain warnings or errors
disable =
invalid-name, # Disable warnings about invalid variable names
missing-docstring, # Disable warnings about missing docstrings

# Enable additional checks
enable =
unused-import, # Enable warnings about unused imports
unused-variable # Enable warnings about unused variables

[BASIC]

# Enforce PEP 8 style conventions
pep

In the next section, you can check out sample programs demonstrating its usage.

Run Pylint with examples

Here is simple Python code where we ran Pytlint. In the output, you can see the -10 rating and find the suggestions. After addressing the issues, the final code is clean and rated 10/10.

Sample program with style issues

Here is a simple program (sample.py) that has some styling issues.

a = 23
b = 45
c = a + b

print(c)

Run pylint

Below is the output after you pass the above sample to Pylint. It lists multiple styling issues in the program.

Check This: The Best 30 Python Questions on Lists, Tuples, and Dictionaries

Use Pylint to detect errors

Fix errors and re-run

After fixing the code, the modified version looks like this:

"""
Code to add two numbers
"""

a = 23
b = 45
c = a + b

print(c)

The output will come as:

Re-run to verify

Python Functions Quiz – A Refresher

Do check out this quiz, if you want to test your comfort level with Python functions.

20 QuestionsAttempt

Enjoy Code Cleanup,
TechBeamers

You Might Also Like

How to Connect to PostgreSQL in Python

Generate Random IP Address (IPv4/IPv6) in Python

Python Remove Elements from a List

Selenium Python Extent Report Guide

10 Python Tricky Coding Exercises

Meenakshi Agarwal Avatar
By Meenakshi Agarwal
Follow:
Hi, I'm Meenakshi Agarwal. I have a Bachelor's degree in Computer Science and a Master's degree in Computer Applications. After spending over a decade in large MNCs, I gained extensive experience in programming, coding, software development, testing, and automation. Now, I share my knowledge through tutorials, quizzes, and interview questions on Python, Java, Selenium, SQL, and C# on my blog, TechBeamers.com.
Previous Article Python Copy Module with Examples Copy Module in Python
Next Article JVM vs JRE vs JDK Introduction to JVM, JDK, JRE

Popular Tutorials

SQL Interview Questions List
50 SQL Practice Questions for Good Results in Interview
SQL Interview Nov 01, 2016
Demo Websites You Need to Practice Selenium
7 Sites to Practice Selenium for Free in 2024
Selenium Tutorial Feb 08, 2016
SQL Exercises with Sample Table and Demo Data
SQL Exercises – Complex Queries
SQL Interview May 10, 2020
Java Coding Questions for Software Testers
15 Java Coding Questions for Testers
Selenium Tutorial Jun 17, 2016
30 Quick Python Programming Questions On List, Tuple & Dictionary
30 Python Programming Questions On List, Tuple, and Dictionary
Python Basic Python Tutorials Oct 07, 2016
//
Our tutorials are written by real people who’ve put in the time to research and test thoroughly. Whether you’re a beginner or a pro, our tutorials will guide you through everything you need to learn a programming language.

Top Coding Tips

  • PYTHON TIPS
  • PANDAS TIPSNew
  • DATA ANALYSIS TIPS
  • SELENIUM TIPS
  • C CODING TIPS
  • GDB DEBUG TIPS
  • SQL TIPS & TRICKS

Top Tutorials

  • PYTHON TUTORIAL FOR BEGINNERS
  • SELENIUM WEBDRIVER TUTORIAL
  • SELENIUM PYTHON TUTORIAL
  • SELENIUM DEMO WEBSITESHot
  • TESTNG TUTORIALS FOR BEGINNERS
  • PYTHON MULTITHREADING TUTORIAL
  • JAVA MULTITHREADING TUTORIAL

Sign Up for Our Newsletter

Subscribe to our newsletter to get our newest articles instantly!

Loading
TechBeamersTechBeamers
Follow US
© 2024 TechBeamers. All Rights Reserved.
  • About
  • Contact
  • Disclaimer
  • Privacy Policy
  • Terms of Use
TechBeamers Newsletter - Subscribe for Latest Updates
Join Us!

Subscribe to our newsletter and never miss the latest tech tutorials, quizzes, and tips.

Loading
Zero spam, Unsubscribe at any time.
x
x