大约有 47,000 项符合查询结果（耗时：0.0330秒） [XML]
What is __future__ in Python used for and how/when to use it, and how it works
__future__ frequently appears in Python modules. I do not understand what __future__ is for and how/when to use it even after reading the Python's __future__ doc .
...
Explaining Python's '__enter__' and '__exit__'
...
Using these magic methods (__enter__, __exit__) allows you to implement objects which can be used easily with the with statement.
The idea is that it makes it easy to build code which needs some 'cleandown' code executed (think of it as a try-finally...
What is the fastest way to get the value of π?
...ically, I'm using ways that don't involve using #define constants like M_PI , or hard-coding the number in.
22 Answers
...
List all the modules that are part of a python package?
...
import email
package = email
for importer, modname, ispkg in pkgutil.iter_modules(package.__path__):
print "Found submodule %s (is a package: %s)" % (modname, ispkg)
How to import them too? You can just use __import__ as normal:
import pkgutil
# this is the package we are inspecting -- for...
Can modules have properties the same way that objects can?
...ance. So, for example, your m.py module file could be:
import sys
class _M(object):
def __init__(self):
self.c = 0
def afunction(self):
self.c += 1
return self.c
y = property(afunction)
sys.modules[__name__] = _M()
...
What exactly does += do in python?
...
In Python, += is sugar coating for the __iadd__ special method, or __add__ or __radd__ if __iadd__ isn't present. The __iadd__ method of a class can do anything it wants. The list object implements it and uses it to iterate over an iterable object appending each...
Python hashable dicts
...another dictionary for obvious reasons.
class hashabledict(dict):
def __hash__(self):
return hash(tuple(sorted(self.items())))
share
|
improve this answer
|
fol...
Finding what methods a Python object has
...this code, replacing 'object' with the object you're interested in:
object_methods = [method_name for method_name in dir(object)
if callable(getattr(object, method_name))]
I discovered it at diveintopython.net (Now archived). Hopefully, that should provide some further detail!
...
List all the files that ever existed in a Git repository
...s with them.
Sample use:
$ git ff create
A database/migrations/2014_10_12_000000_create_users_table.php
A database/migrations/2014_10_12_100000_create_password_resets_table.php
A database/migrations/2015_05_11_200932_create_boletin_table.php
A database/migrations/2015_05_15...
Getting attributes of a class
...gt;> inspect.getmembers(MyClass, lambda a:not(inspect.isroutine(a)))
[('__class__', type),
('__dict__',
<dictproxy {'__dict__': <attribute '__dict__' of 'MyClass' objects>,
'__doc__': None,
'__module__': '__main__',
'__weakref__': <attribute '__weakref__' of 'MyClass' obje...