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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__':...
Why is it impossible to override a getter-only property and add a setter? [closed]
Why is the following C# code not allowed:
16 Answers
16
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Python read-only property
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Generally, Python programs should be written with the assumption that all users are consenting adults, and thus are responsible for using things correctly themselves. However, in the rare instance where it just does not make sens...
What is a higher kinded type in Scala?
...pply to value arguments to "construct" a value.
Value constructors are usually called "functions" or "methods". These "constructors" are also said to be "polymorphic" (because they can be used to construct "stuff" of varying "shape"), or "abstractions" (since they abstract over what varies between ...
Should you always favor xrange() over range()?
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For performance, especially when you're iterating over a large range, xrange() is usually better. However, there are still a few cases why you might prefer range():
In python 3, range() does what xrange() used to do and xrange() does not exist. ...
Naming returned columns in Pandas aggregate function? [duplicate]
...er, this does not work with lambda functions, since they are anonymous and all return <lambda>, which causes a name collision:
>>> df.groupby('A').agg({'B': [lambda x: x.min(), lambda x: x.max]})
SpecificationError: Function names must be unique, found multiple named <lambda>
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what does the __file__ variable mean/do?
I usually just hard-wire these with the actual path. But there is a reason for these statements that determine path at runtime, and I would really like to understand the os.path module so that I can start using it.
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Is there an expression for an infinite generator?
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for x in iter(int, 1): pass
Two-argument iter = zero-argument callable + sentinel value
int() always returns 0
Therefore, iter(int, 1) is an infinite iterator. There are obviously a huge number of variations on this particular theme (especially once you add lambda into the mix). One va...
multiprocessing: sharing a large read-only object between processes?
...ults from stdin, does work, writes intermediate results on stdout.
Connect all the workers as a pipeline:
process1 <source | process2 | process3 | ... | processn >result
Each process reads, does work and writes.
This is remarkably efficient since all processes are running concurrently. T...
How can I multiply and divide using only bit shifting and adding?
...kes a constant multiple of time compared to addition and shifting. If I recall correctly, modern processors, if pipelined properly, can do multiplication just about as fast as addition, by messing with the utilization of the ALUs (arithmetic units) in the processor.
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