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What is an existential type?
... type parameter. Second, invert control (this effectively swaps the "you" and "I" part in the definitions above, which is the primary difference between existentials and universals).
// A wrapper that hides the type parameter 'B'
interface VMWrapper {
void unwrap(VMHandler handler);
}
// A cal...
In practice, what are the main uses for the new “yield from” syntax in Python 3.3?
...ld from is all about. Because, let's face it, if all yield from does is expand the for loop, then it does not warrant adding yield from to the language and preclude a whole bunch of new features from being implemented in Python 2.x.
What yield from does is it establishes a transparent bidirectional...
SPAN vs DIV (inline-block)
...
According to the HTML spec, <span> is an inline element and <div> is a block element. Now that can be changed using the display CSS property but there is one issue: in terms of HTML validation, you can't put block elements inside inline elements so:
<p>...<div>f...
Conditional formatting based on another cell's value
...low, it actually means "B{current_row}", so for C5 it's B5, for C6 it's B6 and so on. Unless you specify $B$5 - then you refer to one specific cell.
This is supported in Google Sheets as of 2015:
https://support.google.com/drive/answer/78413#formulas
In your case, you will need to set conditiona...
What is the difference between a heuristic and an algorithm?
What is the difference between a heuristic and an algorithm?
12 Answers
12
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What is the difference between char s[] and char *s?
...o world";
will place "Hello world" in the read-only parts of the memory, and making s a pointer to that makes any writing operation on this memory illegal.
While doing:
char s[] = "Hello world";
puts the literal string in read-only memory and copies the string to newly allocated memory on the...
When should one use a 'www' subdomain?
When browsing through the internet for the last few years, I'm seeing more and more pages getting rid of the 'www' subdomain.
...
Linux: compute a single hash for a given folder & contents?
...
If there is a whole directory tree, you're probably better off using find and xargs. One possible command would be
find path/to/folder -type f -print0 | sort -z | xargs -0 sha1sum | sha1sum
And, finally, if you also need to take account of permissions and empty directories:
(find path/to/folde...
How many database indexes is too many?
...nds on the operations that occur on the table.
If there's lots of SELECTs and very few changes, index all you like.... these will (potentially) speed the SELECT statements up.
If the table is heavily hit by UPDATEs, INSERTs + DELETEs ... these will be very slow with lots of indexes since they all ...
How to convert TimeStamp to Date in Java?
... @vs06 What makes you think it is deprecated? The latest java 7 and 8 docs both say otherwise (docs.oracle.com/javase/7/docs/api/java/util/Date.html#getTime() and docs.oracle.com/javase/8/docs/api/java/util/Date.html#getTime--)
– Alex Coleman
Sep 22 ...