I am incredibly proud of you all for producing such a great release. As the marketeers would say, "Python 3.3 is the best Python ever!"
The feature list is amazing.
Guido van Rossum
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Before the PEP (Python 2.x, 3.0, 3.1, 3.2):
Two Python builds: narrow and wide
After the PEP (Python 3.3, 3.4, ...):
No more distinctions between narrow and wide
PEP written by Martin von Löwis;
implemented by Torsten Becker
and Martin von Löwis
*.py files are associated to the py launcherPY_PYTHON,
PY_PYTHON3 envvarspy.ini fileExamples:
#! python, #! python3#! /usr/bin/python,
#! /usr/bin/python -vPY_PYTHON values:PY_PYTHON=3, PY_PYTHON3=3.2py.ini values:[defaults]
python=3
python3=3.2py, py foo.pypy -3, py -3.2,
py -3.2 foo.pypy -3.3 -m antigravityPEP written by Mark Hammond
and Martin v. Löwis;
implemented by Vinay Sajip.
venv modules and pyvenv scriptPEP written by Carl Meyer;
implemented by Carl Meyer and
Vinay Sajip.
Usage example:
3.3$ python -m venv venvtest
3.3$ cd venvtest/
3.3/venvtest$ tree
.
├── bin
│ ├── activate
│ ├── pydoc
│ ├── python -> /path/to/3.3/python
│ └── python3 -> python
├── include
├── lib
│ └── python3.3
│ └── site-packages
└── pyvenv.cfg
5 directories, 5 files
3.3/venvtest$ cat pyvenv.cfg
home = /path/to/3.3
include-system-site-packages = false
version = 3.3.0
3.3/venvtest$ python -c 'import sys; print(sys.executable)'
/usr/bin/python
3.3/venvtest$ source bin/activate
(venvtest) 3.3/venvtest$
(venvtest) 3.3/venvtest$ python -c 'import sys; print(sys.executable)'
/path/to/3.3/venvtest/bin/python
(venvtest) 3.3/venvtest$ deactivate
3.3/venvtest$
__init__.py are now supportedPEP written by Eric V. Smith;
implementation by Eric V. Smith.
yield from syntaxyield from iterable is equivalent to
for item in iterable:
yield itemsend()/throw()/close()PEP written by Greg Ewing;
implementation by Greg Ewing et al.
raise SomeError() from None__context__PEP written by Ethan Furman;
implementation by Ethan Furman and
Nick Coghlan
Without context suppression:
>>> try:
... 5/0
... except ZeroDivisionError:
... raise RuntimeError("You can't divide by zero!")
...
Traceback (most recent call last):
File "<stdin>", line 2, in <module>
ZeroDivisionError: division by zero
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "<stdin>", line 4, in <module>
RuntimeError: You can't divide by zero!
With context suppression:
>>> try:
... 5/0
... except ZeroDivisionError:
... raise RuntimeError("You can't divide by zero!") from None
...
Traceback (most recent call last):
File "<stdin>", line 4, in <module>
RuntimeError: You can't divide by zero!
errno anymoreOSError is now an alias for OSError,
IOError, EnvironmentError,
WindowsError, mmap.error,
socket.error and select.errorOSError):
BlockingIOError, ChildProcessError,
ConnectionError, FileExistsError,
FileNotFoundError, InterruptedError,
IsADirectoryError, NotADirectoryError,
PermissionError, ProcessLookupError,
TimeoutErrorConnectionError):
BrokenPipeError, ConnectionAbortedError,
ConnectionRefusedError,
ConnectionResetErrorBefore PEP 3151:
from errno import ENOENT, EACCES, EPERM
try:
with open("document.txt") as f:
content = f.read()
except IOError as err:
if err.errno == ENOENT:
print("document.txt file is missing")
elif err.errno in (EACCES, EPERM):
print("You are not allowed to read document.txt")
else:
raise
After PEP 3151:
try:
with open("document.txt") as f:
content = f.read()
except FileNotFoundError:
print("document.txt file is missing")
except PermissionError:
print("You are not allowed to read document.txt")
PEP written by Antoine Pitrou;
implementation by Antoine Pitrou
__qualname__ attribute for classes and functions__name__, but with the full "path"
(module name excluded)__repr__PEP written by Antoine Pitrou;
implementation by Antoine Pitrou
>>> class Foo:
... def meth(self): pass
... class Bar:
... def meth(self):
... def func(): pass
... return func
...
>>> Foo.__name__, Foo.__qualname__
('Foo', 'Foo')
>>> Foo.meth.__name__, Foo.meth.__qualname__
('meth', 'Foo.meth')
>>> Foo.Bar.__name__, Foo.Bar.__qualname__
('Bar', 'Foo.Bar')
>>> Foo.Bar.meth.__name__, Foo.Bar.meth.__qualname__
('meth', 'Foo.Bar.meth')
>>> Foo.Bar().meth().__name__, Foo.Bar().meth().__qualname__
('func', 'Foo.Bar.meth.<locals>.func')
dict typeobject.__dict__ are shared between instancesPEP written by Mark Shannon;
implementation by Mark Shannon
inspect.signature() functionSignature, Parameter,
and BoundArguments classessignature(obj) returns a
Signature objectsig.parameters is an OrderedDict
of name -> ParameterParameters have name, kind,
default, annotation attrsBoundArguments allows to associate args with
parametersPEP written by Brett Cannon,
Yury Selivanov, Larry Hastings,
Jiwon Seo;
implementation by Yury Selivanov
>>> def foo(a, *, b, c=None): pass
...
>>> sig = inspect.signature(foo)
>>> str(sig)
'(a, *, b, c=None)'
>>> print(sig.parameters)
OrderedDict([('a', <Parameter at 0xb736a474 'a'>),
('b', <Parameter at 0xb73c9574 'b'>),
('c', <Parameter at 0xb73c95b4 'c'>)])
>>> for p in sig.parameters.values():
... print(p.name, p.kind, p.default)
...
a POSITIONAL_OR_KEYWORD <class 'inspect._empty'>
b KEYWORD_ONLY <class 'inspect._empty'>
c KEYWORD_ONLY None
sys.implementation with info about the Python
implementationname, version,
hexversion, and cache_tagname: implementation name,
e.g. 'cpython', 'pypy', 'jython', ...version: a sys.version_info objecthexversion: implementation version in hex formatcache_tag: used in cached modules filenames,
e.g. 'cpython-33'>>> sys.implementation
namespace(cache_tag='cpython-33', hexversion=50528496, name='cpython',
version=sys.version_info(major=3, minor=3, micro=0,
releaselevel='final', serial=0))
types.SimpleNamespace>>> ns = types.SimpleNamespace(foo=15, bar=42)
>>> ns
namespace(bar=42, foo=15)
>>> ns.foo, ns.bar
(15, 42)
>>> ns.foo = 9000
>>> ns
namespace(bar=42, foo=9000)
PEP written by Eric Snow;
implementation by Eric Snow
u'foo' syntax is accepted again
for Unicode stringsPEP written by Armin Ronacher.
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import faulthandler; faulthandler.enable()python -X faulthandlerPYTHONFAULTHANDLERWithout faulthandler:
>>> import ctypes
>>> ctypes.string_at(0)
Segmentation fault (core dumped)
With faulthandler:
>>> import ctypes
>>> ctypes.string_at(0)
Fatal Python error: Segmentation fault
Current thread 0xb77c76c0:
File "/path/to/3.3/Lib/ctypes/__init__.py", line 497 in string_at
File "<stdin>", line 1 in <module>
Segmentation fault (core dumped)
ip_address, IPv4Address,
IPv6Addressip_network, IPv4Network,
IPv6Networkip_interface, IPv4Interface,
IPv6InterfaceAddressValueError,
NetmaskValueErroraddress example:
>>> ipaddr = ip_address('127.0.0.1')
>>> ipaddr
IPv4Address('127.0.0.1')
>>> ipaddr.is_loopback
True
>>> print(str(ipaddr), int(ipaddr))
127.0.0.1 2130706433
>>> next_ipaddr = ipaddr + 1
>>> next_ipaddr
IPv4Address('127.0.0.2')
>>> ipaddr < next_ipaddr
True
network example:
>>> ipnet = ip_network('192.168.1.0/24')
>>> ipnet
IPv4Network('192.168.1.0/24')
>>> list(ipaddr.hosts())
[IPv4Address('192.168.1.1'), IPv4Address('192.168.1.2'), ...,
IPv4Address('192.168.1.253'), IPv4Address('192.168.1.254')]
>>> list(ipnet.subnets())
[IPv4Network('192.168.1.0/25'), IPv4Network('192.168.1.128/25')]
>>> ipnet.supernet()
IPv4Network('192.168.0.0/23')
>>> ipnet[10]
IPv4Address('192.168.1.10')
>>> ipnet[10] in ipnet
True
Reading example:
>>> with lzma.open("file.xz") as f:
... file_content = f.read()
Writing example:
>>> with lzma.open("file.xz", "w") as f:
... f.write(b"data to be compressed")
Mock objectpatch decorator/context managerMock example:
>>> from unittest.mock import MagicMock
>>> thing = ProductionClass()
>>> thing.method = MagicMock(return_value=3)
>>> thing.method(3, 4, 5, key='value')
3
>>> thing.method.assert_called_with(3, 4, 5, key='value')
>>> mock = Mock(side_effect=KeyError('foo'))
>>> mock()
Traceback (most recent call last):
...
KeyError: 'foo'
patch example:
>>> def func():
... sys.exit('farewell')
...
>>> @patch('sys.exit')
... def test(mock_exit):
... func()
... mock_exit.assert_called_once_with('farewell')
...
>>> test()
>>>
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urlopen(Request('http://www.python.org', method='HEAD'))Questions?