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Find difference between timestamps in seconds in PostgreSQL
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Try:
SELECT EXTRACT(EPOCH FROM (timestamp_B - timestamp_A))
FROM TableA
Details here: EXTRACT.
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How does the MapReduce sort algorithm work?
... 1 sampled keys that define the key range for each reduce. In particular, all keys such that sample[i − 1] <= key < sample[i] are sent to reduce i. This guarantees that the output of reduce i are all less than the output of reduce i+1."
So their trick is in the way they determine the keys ...
Block Declaration Syntax List
...at this is distinct from "Blocks as Parameters"; in this instance, you're calling a method that wants a block argument with an anonymous block. If you have already declared a block variable, it is sufficient to pass the variable name as the argument.
[someObject doSomethingWithBlock: ^return_type (...
Javascript Drag and drop for touch devices [closed]
...r("touchcancel", touchHandler, true);
}
And in your document.ready just call the init() function
code found from Here
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Using Pairs or 2-tuples in Java [duplicate]
...to design this class further regarding equality, immutability, etc., especially if you plan to use instances as keys for hashing.
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Sequence contains no elements?
...boxes for the title and content, the ID and date aren't put on the page at all. Could this be the reason for it passing them as null\new?
– Andy Hunt
Aug 24 '09 at 19:43
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Bold & Non-Bold Text In A Single UILabel?
...deal with iOS5 old stuff besides syntax is shorter so everything becomes really simple:
Swift 5
func attributedString(from string: String, nonBoldRange: NSRange?) -> NSAttributedString {
let fontSize = UIFont.systemFontSize
let attrs = [
NSAttributedString.Key.font: UIFont.bold...
How to clear MemoryCache?
...clear it first. What is the quickest way to do this? Should I loop through all the items and remove them one at a time or is there a better way?
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Numpy `logical_or` for more than two arguments
... no, as the docs explicitly say, the only parameters are x1, x2, and optionally out:
numpy.logical_or(x1, x2[, out]) = <ufunc 'logical_or'>
You can of course chain together multiple logical_or calls like this:
>>> x = np.array([True, True, False, False])
>>> y = np.a...
What happens when there's insufficient memory to throw an OutOfMemoryError?
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The JVM never really runs out of memory. It does memory computation of the heap stack in advance.
The Structure of the JVM, Chapter 3, section 3.5.2 states:
If Java virtual machine stacks can be dynamically expanded, and expansion is...