Some of its key distinguishing features include:
- very clear, readable syntax
- strong introspection capabilities
- intuitive object orientation
- natural expression of procedural code
- full modularity, supporting hierarchical packages
- exception-based error handling
- very high level dynamic data types
- extensive standard libraries and third party modules for virtually every task
- extensions and modules easily written in C, C++ (or Java for Jython, or .NET languages for IronPython)
- embeddable within applications as a scripting interface
Python is powerful... and fast
Fans of Python use the phrase "batteries included" to describe the standard library, which covers everything from asynchronous processing to zip files. The language itself is a flexible powerhouse that can handle practically any problem domain. Build your own web server in three lines of code. Build flexible data-driven code using Python's powerful and dynamic introspection capabilities and advanced language features such as meta-classes, duck typing and decorators.
Python lets you write the code you need, quickly. And, thanks to a highly optimized byte compiler and support libraries, Python code runs more than fast enough for most applications. The traditional implementation of CPython uses a bytecode virtual machine; PyPy supports just-in-time (JIT) compilation to machine code. Also, Jython and IronPython (see below) support JIT compilation on their respective virtual machine implementations.
Python plays well with others
Python can integrate with COM, .NET, and CORBA objects.
For Java libraries, use Jython, an implementation of Python for the Java Virtual Machine.
For .NET, try IronPython , Microsoft's new implementation of Python for .NET, or Python for .NET.
Python is also supported for the Internet Communications Engine (ICE) and many other integration technologies.
If you find something that Python cannot do, or if you need the performance advantage of low-level code, you can write extension modules in C or C++, or wrap existing code with SWIG or Boost.Python. Wrapped modules appear to your program exactly like native Python code. That's language integration made easy. You can also go the opposite route and embed Python in your own application, providing your users with a language they'll enjoy using.
Python runs everywhere
Python is available for all major operating systems: Windows, Linux/Unix, OS/2, Mac, Amiga, among others. There are even versions that run on .NET and the Java virtual machine. You'll be pleased to know that the same source code will run unchanged across all implementations.
Your favorite system isn't listed here? It may still support Python if there's a C compiler for it. Ask around on news:comp.lang.python - or just try compiling Python yourself.
Python is friendly... and easy to learn
The Python newsgroup is known as one of the friendliest around. The avid developer and user community maintains a wiki, hosts international and local conferences, runs development sprints, and contributes to online code repositories.
Python also comes with complete documentation, both integrated into the language and as separate web pages. Online tutorials target both the seasoned programmer and the newcomer. All are designed to make you productive quickly. The availability of first-rate books completes the learning package.
Python is Open
The Python implementation is under an open source license that makes it freely usable and distributable, even for commercial use. The Python license is administered by the Python Software Foundation.
Take a look at application domains where Python is used, or try the current download for yourself.
Python 3.9.4 is a hotfix release addressing an unintentional ABI incompatibility introduced in Python 3.9.3. Upgrading is highly recommended to all users. Details in bpo-43710.
To reiterate, Python 3.9.3 was itself an expedited release due to its security content:
- bpo-43631: high-severity CVE-2021-3449 and CVE-2021-3450 were published for OpenSSL, it's been upgraded to 1.1.1k in CI, and macOS and Windows installers.
- bpo-42988: CVE-2021-3426: Remove the getfile feature of the pydoc module which could be abused to read arbitrary files on the disk (directory traversal vulnerability). Moreover, even source code of Python modules can contain sensitive data like passwords. Vulnerability reported by David Schwörer.
- bpo-43285: ftplib no longer trusts the IP address value returned from the server in response to the PASV command by default. This prevents a malicious FTP server from using the response to probe IPv4 address and port combinations on the client network. Code that requires the former vulnerable behavior may set a trust_server_pasv_ipv4_address attribute on their ftplib.FTP instances to True to re-enable it.
- bpo-43439: Add audit hooks for gc.get_objects(), gc.get_referrers() and gc.get_referents(). Patch by Pablo Galindo.
Major new features of the 3.9 series, compared to 3.8
- Some of the new major new features and changes in Python 3.9 are:
- PEP 573, Module State Access from C Extension Methods
- PEP 584, Union Operators in dict
- PEP 585, Type Hinting Generics In Standard Collections
- PEP 593, Flexible function and variable annotations
- PEP 602, Python adopts a stable annual release cadence
- PEP 614, Relaxing Grammar Restrictions On Decorators
- PEP 615, Support for the IANA Time Zone Database in the Standard Library
- PEP 616, String methods to remove prefixes and suffixes
- PEP 617, New PEG parser for CPython
- BPO 38379, garbage collection does not block on resurrected objects;
- BPO 38692, os.pidfd_open added that allows process management without races and signals;
- BPO 39926, Unicode support updated to version 13.0.0;
- BPO 1635741, when Python is initialized multiple times in the same process, it does not leak memory anymore;
- A number of Python builtins (range, tuple, set, frozenset, list, dict) are now sped up using PEP 590 vectorcall;
- A number of Python modules (_abc, audioop, _bz2, _codecs, _contextvars, _crypt, _functools, _json, _locale, operator, resource, time, _weakref) now use multiphase initialization as defined by PEP 489;
- A number of standard library modules (audioop, ast, grp, _hashlib, pwd, _posixsubprocess, random, select, struct, termios, zlib) are now using the stable ABI defined by PEP 384.