Python Language
- Getting started with Python Language
- Awesome Book
- Awesome Community
- Awesome Course
- Awesome Tutorial
- Awesome YouTube
- *args and **kwargs
- 2to3 tool
- Abstract Base Classes (abc)
- Abstract syntax tree
- Accessing Python source code and bytecode
- Alternatives to switch statement from other languages
- ArcPy
- Arrays
- Asyncio Module
- Attribute Access
- Audio
- Basic Curses with Python
- Basic Input and Output
- Binary Data
- Bitwise Operators
- Boolean Operators
- Call Python from C#
- Checking Path Existence and Permissions
- ChemPy - python package
- Classes
- CLI subcommands with precise help output
- Code blocks, execution frames, and namespaces
- Collections module
- Comments and Documentation
- Common Pitfalls
- Commonwealth Exceptions
- Comparisons
- Complex math
- Conditionals
- configparser
- Connecting Python to SQL Server
- Context Managers (“with” Statement)
- Copying data
- Counting
- Create virtual environment with virtualenvwrapper in windows
- Creating a Windows service using Python
- Creating Python packages
- ctypes
- Data Serialization
- Data Visualization with Python
- Database Access
- Date and Time
- Date Formatting
- Debugging
- Decorators
- Defining functions with list arguments
- Deployment
- Deque Module
- Descriptor
- Design Patterns
- Dictionary
- Difference between Module and Package
- Distribution
- Django
- Dynamic code execution with `exec` and `eval`
- Enum
- Exceptions
- Exponentiation
- Files & Folders I/O
- Filter
- Flask
- Functional Programming in Python
- Functions
- Functools Module
- Garbage Collection
- Generators
- getting start with GZip
- graph-tool
- groupby()
- hashlib
- Heapq
- Hidden Features
- HTML Parsing
- Idioms
- ijson
- Immutable datatypes(int, float, str, tuple and frozensets)
- Importing modules
- Incompatibilities moving from Python 2 to Python 3
- .next() method on iterators renamed
- Absolute/Relative Imports
- All classes are "new-style classes" in Python 3.
- Class Boolean Value
- cmp function removed in Python 3
- Comparison of different types
- Dictionary method changes
- Differences between range and xrange functions
- encode/decode to hex no longer available
- exec statement is a function in Python 3
- File I/O
- filter(), map() and zip() return iterators instead of sequences
- hasattr function bug in Python 2
- Integer Division
- Leaked variables in list comprehension
- long vs. int
- map()
- Octal Constants
- Print statement vs. Print function
- Raising and handling Exceptions
- Reduce is no longer a built-in
- Removed operators <> and ``, synonymous with != and repr()
- Renamed modules
- Return value when writing to a file object
- Strings: Bytes versus Unicode
- The round() function tie-breaking and return type
- True, False and None
- Unpacking Iterables
- User Input
- Indentation
- Indexing and Slicing
- Input, Subset and Output External Data Files using Pandas
- Introduction to RabbitMQ using AMQPStorm
- IoT Programming with Python and Raspberry PI
- Iterables and Iterators
- Itertools Module
- JSON Module
- kivy - Cross-platform Python Framework for NUI Development
- Linked List Node
- Linked lists
- List
- List comprehensions
- List Comprehensions
- List destructuring (aka packing and unpacking)
- List slicing (selecting parts of lists)
- Logging
- Loops
- Manipulating XML
- Map Function
- Math Module
- Metaclasses
- Method Overriding
- Mixins
- Multidimensional arrays
- Multiprocessing
- Multithreading
- Mutable vs Immutable (and Hashable) in Python
- Neo4j and Cypher using Py2Neo
- Non-official Python implementations
- Operator module
- Operator Precedence
- Optical Character Recognition
- os.path
- Overloading
- Pandas Transform: Preform operations on groups and concatenate the results
- Parallel computation
- Parsing Command Line arguments
- Partial functions
- Performance optimization
- Pickle data serialisation
- Pillow
- pip: PyPI Package Manager
- Plotting with Matplotlib
- Plugin and Extension Classes
- Polymorphism
- PostgreSQL
- Processes and Threads
- Profiling
- Property Objects
- py.test
- pyaudio
- pyautogui module
- pygame
- Pyglet
- PyInstaller - Distributing Python Code
- Python and Excel
- Python Anti-Patterns
- Python concurrency
- Python Data Types
- Python HTTP Server
- Python Lex-Yacc
- Python Networking
- Python Persistence
- Python Requests Post
- Python Serial Communication (pyserial)
- Python Server Sent Events
- Python speed of program
- Python Virtual Environment - virtualenv
- Queue Module
- Raise Custom Errors / Exceptions
- Random module
- Reading and Writing CSV
- Recursion
- Reduce
- Regular Expressions (Regex)
- Searching
- Secure Shell Connection in Python
- Security and Cryptography
- Set
- setup.py
- shelve
- Similarities in syntax, Differences in meaning: Python vs. JavaScript
- Simple Mathematical Operators
- Sockets
- Sockets And Message Encryption/Decryption Between Client and Server
- Sorting, Minimum and Maximum
- Sqlite3 Module
- Stack
- String Formatting
- String Methods
- String representations of class instances: __str__ and __repr__ methods
- Subprocess Library
- sys
- tempfile NamedTemporaryFile
- Templates in python
- The __name__ special variable
- The base64 Module
- The dis module
- The Interpreter (Command Line Console)
- The locale Module
- The os Module
- The pass statement
- The Print Function
- tkinter
- Tuple
- Turtle Graphics
- Type Hints
- Unicode
- Unicode and bytes
- Unit Testing
- Unzipping Files
- urllib
- Usage of "pip" module: PyPI Package Manager
- User-Defined Methods
- Using loops within functions
- Variable Scope and Binding
- virtual environment with virtualenvwrapper
- Virtual environments
- Web scraping with Python
- Web Server Gateway Interface (WSGI)
- Webbrowser Module
- Websockets
- Working around the Global Interpreter Lock (GIL)
- Working with ZIP archives
- Writing extensions
- Writing to CSV from String or List
Python Language Incompatibilities moving from Python 2 to Python 3
Introduction
Unlike most languages, Python supports two major versions. Since 2008 when Python 3 was released, many have made the transition, while many have not. In order to understand both, this section covers the important differences between Python 2 and Python 3.
Remarks
There are currently two supported versions of Python: 2.7 (Python 2) and 3.6 (Python 3). Additionally versions 3.3 and 3.4 receive security updates in source format.
Python 2.7 is backwards-compatible with most earlier versions of Python, and can run Python code from most 1.x and 2.x versions of Python unchanged. It is broadly available, with an extensive collection of packages. It is also considered deprecated by the CPython developers, and receives only security and bug-fix development. The CPython developers intend to abandon this version of the language in 2020.
According to Python Enhancement Proposal 373 there are no planned future releases of Python 2 after 25 June 2016, but bug fixes and security updates will be supported until 2020. (It doesn't specify what exact date in 2020 will be the sunset date of Python 2.)
Python 3 intentionally broke backwards-compatibility, to address concerns the language developers had with the core of the language. Python 3 receives new development and new features. It is the version of the language that the language developers intend to move forward with.
Over the time between the initial release of Python 3.0 and the current version, some features of Python 3 were back-ported into Python 2.6, and other parts of Python 3 were extended to have syntax compatible with Python 2. Therefore it is possible to write Python that will work on both Python 2 and Python 3, by using future imports and special modules (like six).
Future imports have to be at the beginning of your module:
from __future__ import print_function
# other imports and instructions go after __future__
print('Hello world')
For further information on the __future__ module, see the relevant page in the Python documentation.
The 2to3 tool is a Python program that converts Python 2.x code to Python 3.x code, see also the Python documentation.
The package six provides utilities for Python 2/3 compatibility:
- unified access to renamed libraries
- variables for string/unicode types
- functions for method that got removed or has been renamed
A reference for differences between Python 2 and Python 3 can be found here.
Incompatibilities moving from Python 2 to Python 3 Related Examples
- .next() method on iterators renamed
- Absolute/Relative Imports
- All classes are "new-style classes" in Python 3.
- Class Boolean Value
- cmp function removed in Python 3
- Comparison of different types
- Dictionary method changes
- Differences between range and xrange functions
- encode/decode to hex no longer available
- exec statement is a function in Python 3
- File I/O
- filter(), map() and zip() return iterators instead of sequences
- hasattr function bug in Python 2
- Integer Division
- Leaked variables in list comprehension
- long vs. int
- map()
- Octal Constants
- Print statement vs. Print function
- Raising and handling Exceptions
- Reduce is no longer a built-in
- Removed operators <> and ``, synonymous with != and repr()
- Renamed modules
- Return value when writing to a file object
- Strings: Bytes versus Unicode
- The round() function tie-breaking and return type
- True, False and None
- Unpacking Iterables
- User Input
