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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
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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.
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Why does the expression 0 < 0 == 0 return False in Python?
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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 < x <= 5 than to say (0 < x) and (x <= 5).
These are called chained comparisons. And th...
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...
Python constructors and __init__
Why are constructors indeed called "Constructors"? What is their purpose and how are they different from methods in a class?
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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.
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How to properly assert that an exception gets raised in pytest?
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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...
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...
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...
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...