大约有 46,000 项符合查询结果（耗时：0.0325秒） [XML]
__getattr__ on a module
...le, use a module as a context manager simply by defining __enter__ and __exit__, before those tricks broke.
Recently some historical features have made a comeback, the module __getattr__ among them, and so the existing hack (a module replacing itself with a class in sys.modules at import time) sho...
Are static class variables possible in Python?
Is it possible to have static class variables or methods in Python? What syntax is required to do this?
21 Answers
...
Difference between left join and right join in SQL Server [duplicate]
...indeed completely interchangeable. Try however Table2 left join Table1 (or its identical pair, Table1 right join Table2) to see a difference. This query should give you more rows, since Table2 contains a row with an id which is not present in Table1.
...
Print all properties of a Python Class [duplicate]
I have a class Animal with several properties like:
6 Answers
6
...
Finding what methods a Python object has
...
For many objects, you can use 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...
A python class that acts like dict
I want to write a custom class that behaves like dict - so, I am inheriting from dict .
9 Answers
...
What is the meaning of single and double underscore before an object name?
...
Single Underscore
Names, in a class, with a leading underscore are simply to indicate to other programmers that the attribute or method is intended to be private. However, nothing special is done with the name itself.
To quote PEP-8:
_single_leading_undersc...
What is __main__.py?
What is the __main__.py file for, what sort of code should I put into it, and when should I have one?
5 Answers
...
What __init__ and self do on Python?
...
In this code:
class A(object):
def __init__(self):
self.x = 'Hello'
def method_a(self, foo):
print self.x + ' ' + foo
... the self variable represents the instance of the object itself. Most object-oriented languages pass this as a hidden p...
What are some (concrete) use-cases for metaclasses?
... Matplotlib. However, on occasion one wants to do interactive plotting. With only a couple functions I found that I was able to increment the figure count, call draw manually, etc, but I needed to do these before and after every plotting call. So to create both an interactive plotting wrapper and...