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Hidden features of Scala
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trait Functor[F[_]] {
def fmap[A, B](f: A => B, fa: F[A]): F[B]
}
Now, if you have a Functor[List], you can map over lists. If you have a Functor[Tree], you can map over trees. But more importantly, if you have Functor[A] for any A of kind (*->*), you can map a function over A.
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Handling a colon in an element ID in a CSS selector [duplicate]
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This article will tell you how to escape any character in CSS.
Now, there’s even a tool for it: http://mothereff.in/css-escapes#0search%5fform%3Aexpression
TL;DR All the other answers to this question are incorrect. You need to escape both the underscore (to prevent IE6 from ignoring ...
python: How do I know what type of exception occurred?
...y, it's so that you don't hide:
the fact that an error occurred
the specifics of the error that occurred (error hiding antipattern)
So as long as you take care to do none of those things, it's OK to catch the generic exception. For instance, you could provide information about the exception to ...
RuntimeError on windows trying python multiprocessing
...will import (i.e. execute) the main module at start. You need to insert an if __name__ == '__main__': guard in the main module to avoid creating subprocesses recursively.
Modified testMain.py:
import parallelTestModule
if __name__ == '__main__':
extractor = parallelTestModule.ParallelExt...
What are the Dangers of Method Swizzling in Objective-C?
... calls that, but the _cmd argument isn't setFrame: like it should be. It's now my_setFrame:. The original implementation is being called with an argument it never expected it would receive. This is no good.
There's a simple solution — use the alternative swizzling technique defined above. The arg...
Why do people say that Ruby is slow? [closed]
...e signal processing app. It's easier to see what people are talking about now after all these helpful answers.
– stephenmurdoch
Apr 27 '10 at 3:13
1
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Define a lambda expression that raises an Exception
...ef raise_(ex):
raise ex
y = lambda: raise_(Exception('foobar'))
But if your goal is to avoid a def, this obviously doesn't cut it. It does, however allow you to conditionally raise exceptions, e.g.:
y = lambda x: 2*x if x < 10 else raise_(Exception('foobar'))
Alternatively you can rai...
Show all Elasticsearch aggregation results/buckets and not just 10
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Note that setting size:0 is now deprecated, due to memory issues inflicted on your cluster with high-cardinality field values. github.com/elastic/elasticsearch/issues/18838. Instead, use a real, reasonable number between 1 to 2147483647.
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What is the purpose of python's inner classes?
...es confuse me. Is there something that can't be accomplished without them? If so, what is that thing?
9 Answers
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Python multiprocessing pool.map for multiple arguments
...ort product
def merge_names(a, b):
return '{} & {}'.format(a, b)
if __name__ == '__main__':
names = ['Brown', 'Wilson', 'Bartlett', 'Rivera', 'Molloy', 'Opie']
with multiprocessing.Pool(processes=3) as pool:
results = pool.starmap(merge_names, product(names, repeat=2))
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