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Is it ever advantageous to use 'goto' in a language that supports loops and functions? If so, why?
...o this already):
Cleanly exiting a function
Often in a function, you may allocate resources and need to exit in multiple places. Programmers can simplify their code by putting the resource cleanup code at the end of the function, and all "exit points" of the function would goto the cleanup label....
What is the most effective way for float and double comparison?
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Be extremely careful using any of the other suggestions. It all depends on context.
I have spent a long time tracing a bugs in a system that presumed a==b if |a-b|<epsilon. The underlying problems were:
The implicit presumption in an algorithm that if a==b and b==c then a==c.
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Difference between left join and right join in SQL Server [duplicate]
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@SilapAliyev That's actually a very good question. Can anyone answer? :D
– Ian Chu Te
Jan 8 '16 at 2:46
21
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Python dictionary from an object's fields
...a dictionary from an arbitrary object, it's sufficient to use __dict__. Usually, you'll declare your methods at class level and your attributes at instance level, so __dict__ should be fine. For example:
>>> class A(object):
... def __init__(self):
... self.b = 1
... self.c = 2
....
Can someone explain __all__ in Python?
I have been using Python more and more, and I keep seeing the variable __all__ set in different __init__.py files. Can someone explain what this does?
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What is the meaning of single and double underscore before an object name?
...at least two leading underscores, at most one trailing underscore) is textually replaced with _classname__spam, where classname is the current class name with leading underscore(s) stripped. This mangling is done without regard to the syntactic position of the identifier, so it can be used to define...
Why is `std::move` named `std::move`?
The C++11 std::move(x) function doesn't really move anything at all. It is just a cast to r-value. Why was this done? Isn't this misleading?
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Python's equivalent of && (logical-and) in an if-statement
... different name in Python.
The logical operators && and || are actually called and and or.
Likewise the logical negation operator ! is called not.
So you could just write:
if len(a) % 2 == 0 and len(b) % 2 == 0:
or even:
if not (len(a) % 2 or len(b) % 2):
Some additional information (...
Method Resolution Order (MRO) in new-style classes?
...ject'>)
with A forced to come in resolution order only once and after all of its subclasses, so that overrides (i.e., C's override of member x) actually work sensibly.
It's one of the reasons that old-style classes should be avoided: multiple inheritance with "diamond-like" patterns just doesn...
Python multiprocessing pool.map for multiple arguments
...rmap method, which accepts a sequence of argument tuples. It then automatically unpacks the arguments from each tuple and passes them to the given function:
import multiprocessing
from itertools import product
def merge_names(a, b):
return '{} & {}'.format(a, b)
if __name__ == '__main__':...