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Why aren't superclass __init__ methods automatically invoked?
Why did the Python designers decide that subclasses' __init__() methods don't automatically call the __init__() methods of their superclasses, as in some other languages? Is the Pythonic and recommended idiom really like the following?
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Why does using an Underscore character in a LIKE filter give me all the results?
...
Modify your WHERE condition like this:
WHERE mycolumn LIKE '%\_%' ESCAPE '\'
This is one of the ways in which Oracle supports escape characters. Here you define the escape character with the escape keyword. For details see this link on Oracle Docs.
The '_' and '%' are wildcards in a ...
Programmatically Request Access to Contacts
... // First time access has been granted, add the contact
[self _addContactToAddressBook];
} else {
// User denied access
// Display an alert telling user the contact could not be added
}
});
}
else if (ABAddressBookGetAuthorizationStatus() == kABAu...
Elegant ways to support equivalence (“equality”) in Python classes
... and != operators. In Python, this is made possible by implementing the __eq__ and __ne__ special methods, respectively. The easiest way I've found to do this is the following method:
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Getting list of parameter names inside python function [duplicate]
....
>>> func = lambda x, y: (x, y)
>>>
>>> func.__code__.co_argcount
2
>>> func.__code__.co_varnames
('x', 'y')
>>>
>>> def func2(x,y=3):
... print(func2.__code__.co_varnames)
... pass # Other things
...
>>> func2(3,3)
('x', 'y')
>...
lodash multi-column sortBy descending
...ash 3.5.0 you can use sortByOrder (renamed orderBy in v4.3.0):
var data = _.sortByOrder(array_of_objects, ['type','name'], [true, false]);
Since version 3.10.0 you can even use standard semantics for ordering (asc, desc):
var data = _.sortByOrder(array_of_objects, ['type','name'], ['asc', 'desc'...
When I catch an exception, how do I get the type, file, and line number?
...y:
raise NotImplementedError("No error")
except Exception as e:
exc_type, exc_obj, exc_tb = sys.exc_info()
fname = os.path.split(exc_tb.tb_frame.f_code.co_filename)[1]
print(exc_type, fname, exc_tb.tb_lineno)
...
Are nested try/except blocks in python a good programming practice?
...EAFP.
Personally, I prefer to avoid nesting when it's not necessary:
def __getattribute__(self, item):
try:
return object.__getattribute__(item)
except AttributeError:
pass # fallback to dict
try:
return self.dict[item]
except KeyError:
raise Attrib...
What is time_t ultimately a typedef to?
...
The time_t Wikipedia article article sheds some light on this. The bottom line is that the type of time_t is not guaranteed in the C specification.
The time_t datatype is a data type in
the ISO C library defined for storing
s...
How to compare type of an object in Python?
...
isinstance works:
if isinstance(obj, MyClass): do_foo(obj)
but, keep in mind: if it looks like a duck, and if it sounds like a duck, it is a duck.
EDIT: For the None type, you can simply do:
if obj is None: obj = MyClass()
...