大约有 43,000 项符合查询结果(耗时:0.0546秒) [XML]

https://stackoverflow.com/ques... 

List attributes of an object

...t list attributes' -- A way to inspect an instance of an unfamiliar object and find out what it's like. – JDenman6 Aug 21 at 15:14 add a comment  |  ...
https://stackoverflow.com/ques... 

python NameError: global name '__file__' is not defined

...ractive shell. Python Shell doesn't detect current file path in __file__ and it's related to your filepath in which you added this line So you should write this line os.path.join(os.path.dirname(__file__)) in file.py. and then run python file.py, It works because it takes your filepath. ...
https://stackoverflow.com/ques... 

Why does the expression 0 < 0 == 0 return False in Python?

... I believe Python has special case handling for sequences of relational operators to make range comparisons easy to express. It's much nicer to be able to say 0 &lt; x &lt;= 5 than to say (0 &lt; x) and (x &lt;= 5). These are called chained comparisons. And th...
https://stackoverflow.com/ques... 

Why is “if not someobj:” better than “if someobj == None:” in Python?

... the object has a __nonzero__ special method (as do numeric built-ins, int and float), it calls this method. It must either return a bool value which is then directly used, or an int value that is considered False if equal to zero. Otherwise, if the object has a __len__ special method (as do contain...
https://stackoverflow.com/ques... 

Python constructors and __init__

Why are constructors indeed called "Constructors"? What is their purpose and how are they different from methods in a class? ...
https://stackoverflow.com/ques... 

Is module __file__ attribute absolute or relative?

I'm having trouble understanding __file__ . From what I understand, __file__ returns the absolute path from which the module was loaded. ...
https://stackoverflow.com/ques... 

How to properly assert that an exception gets raised in pytest?

... There are two ways to handle these kind of cases in pytest: Using pytest.raises function Using pytest.mark.xfail decorator As the documentation says: Using pytest.raises is likely to be better for cases where you are testing exceptions your ow...
https://stackoverflow.com/ques... 

Hashing a dictionary?

...dictionary is not nested, you could make a frozenset with the dict's items and use hash(): hash(frozenset(my_dict.items())) This is much less computationally intensive than generating the JSON string or representation of the dictionary. UPDATE: Please see the comments below, why this approach mi...
https://stackoverflow.com/ques... 

How to print instances of a class using print()?

...(t) member of Test The __str__ method is what happens when you print it, and the __repr__ method is what happens when you use the repr() function (or when you look at it with the interactive prompt). If this isn't the most Pythonic method, I apologize, because I'm still learning too - but it works...
https://stackoverflow.com/ques... 

Why does Python code use len() function instead of a length method?

...tocol in Python is to implement this method on objects which have a length and use the built-in len() function, which calls it for you, similar to the way you would implement __iter__() and use the built-in iter() function (or have the method called behind the scenes for you) on objects which are it...