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Simple explanation of MapReduce?
...rite it like this
A = [7, 8, 9]
sum = A.reduce( 0, (x, y) => x + y )
Now it's a little confusing why there are 2 arguments (0 and the function with x and y) passed. For a reduce function to be useful, it must be able to take 2 items, compute something and "reduce" that 2 items to just one sing...
Iterate over object attributes in python
...ppens if I just harmlessly add an attribute to the class, a name, say, and now all of a sudden it gets included.
– Julian
Jul 24 '12 at 19:16
3
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django unit tests without a db
...to : from django.test.runner import DiscoverRunner The NoDbTestRunner must now extend the DiscoverRunner class.
– Aditya Satyavada
Mar 30 '18 at 6:44
...
When to use virtual destructors?
...Here, you'll notice that I didn't declare Base's destructor to be virtual. Now, let's have a look at the following snippet:
Base *b = new Derived();
// use b
delete b; // Here's the problem!
Since Base's destructor is not virtual and b is a Base* pointing to a Derived object, delete b has undefin...
How to find the kth largest element in an unsorted array of length n in O(n)?
...∑i=floor(n/2) to n T(i)
<= cn + 2 (1/n) ∑i=floor(n/2) to n ai
and now somehow we have to get the horrendous sum on the right of the plus sign to absorb the cn on the left. If we just bound it as 2(1/n) ∑i=n/2 to n an, we get roughly 2(1/n)(n/2)an = an. But this is too big - there's no r...
What are the key differences between Apache Thrift, Google Protocol Buffers, MessagePack, ASN.1 and
...t about other libraries and how it's usable in common? Also, it seems Avro now has IDL with C-like syntax in addition to JSON one.
– andreypopp
Jan 8 '11 at 12:30
2
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Why do I need to explicitly push a new branch?
...same name, creating them if they don't exist),
the default push policy is now 'simple' (push only the current branch, and only if it has a similarly named remote tracking branch on upstream, since git 1.7.11)
In both cases, since the upstream empty repo has no branch:
there is no matching named...
SQL query for today's date minus two months
...
If you use MySQL this would become: MyDate < DATE_ADD(NOW(), INTERVAL -2 MONTH)
– Stefan
Feb 27 '14 at 15:51
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How to convert a DOM node list to an array in Javascript?
...obj[i];
}
return array;
}
UPDATE:
As other answers suggest, you can now can use in modern environments the spread syntax or the Array.from method:
const array = [ ...nodeList ] // or Array.from(nodeList)
But thinking about it, I guess the most common use case to convert a NodeList to an Ar...
What is the purpose of Rank2Types?
...f' :: forall r. Num r => (Int -> r) -> Int -> Int -> r, and now we have fixed the g argument so it can take Int but not String. If we enable RankNTypes we can annotate f' with type forall b c r. Num r => (forall a. a -> r) -> b -> c -> r. Can't use it, though—what wou...