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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...
Why is rbindlist “better” than rbind?
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rbindlist is an optimized version of do.call(rbind, list(...)), which is known for being slow when using rbind.data.frame
Where does it really excel
Some questions that show where rbindlist shines are
Fast vectorized merge of list of data.frames by row
Trouble converting long list of data.fra...
Redirect all to index.php using htaccess
...updated Feb '18 and Jan '19)
It's not actually necessary (nor even common now) to set the path as a $_GET variable, many frameworks will rely on $_SERVER['REQUEST_URI'] to retrieve the same information - normally to determine which Controller to use - but the principle is exactly the same.
This do...
Why doesn't Ruby support i++ or i-- (increment/decrement operators)?
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One reason is that up to now every assignment operator (i.e. an operator which changes a variable) has a = in it. If you add ++ and --, that's no longer the case.
Another reason is that the behavior of ++ and -- often confuse people. Case in point: ...
Difference between “git add -A” and “git add .”
... -A ..
git add <path> is the same as "git add -A <path>" now, so that
"git add dir/" will notice paths you removed from the directory and
record the removal.
In older versions of Git, "git add <path>" ignored removals.
You can say "git add --ignore-removal <pa...
Default filter in Django admin
...otes... it requires Django 1.4, though, although that should be a given by now.
– Simon
May 16 '13 at 21:58
@Greg How ...
Java 8: Where is TriFunction (and kin) in java.util.function? Or what is the alternative?
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As far as I know, there are only two kinds of functions, destructive and constructive.
While constructive function, as the name implies, constructs something, a destructive one destroys something, but not in the way you may think now.
F...
How can I force a hard reload in Chrome for Android
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Now its changed to Clear Browsing Data, where you can check clear cache using check box.
– shaijut
Dec 3 '15 at 7:39
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Hibernate, @SequenceGenerator and allocationSize
We all know the default behaviour of Hibernate when using @SequenceGenerator - it increases real database sequence by one , multiple this value by 50 (default allocationSize value) - and then uses this value as entity ID.
...
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...