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What database does Google use?
...
Do anyone know if it was that built from scratch or based on some product? I heard somewhere I don't remember where, that google used Oracle once, but they drop it because they need some modifications that Oracle won't do nor allow them...
Why do we need a pure virtual destructor in C++?
...class Base
{
public:
Base();
virtual ~Base() = 0; // Pure virtual, now no one can create the Base Object directly
};
Base::Base() { cout << "Base Constructor" << endl; }
Base::~Base() { cout << "Base Destructor" << endl; }
class Derived : public Base
{
public:
...
Assign a variable inside a Block to a variable outside a Block
...Person *strongPerson = [Person new];
__weak Person *weakPerson = person;
Now you can refer weakPerson object inside block.
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Numpy: Get random set of rows from 2D array
...mask = numpy.random.choice([False, True], len(data_arr), p=[0.75, 0.25])
Now you can call data_arr[mask] and return ~25% of the rows, randomly sampled.
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eval command in Bash and its typical uses
...s put double quotes around variable and command substitutions, unless you know you need to leave them off. Without the double quotes, the shell performs field splitting (i.e. it splits value of the variable or the output from the command into separate words) and then treats each word as a wildcard p...
java.lang.IllegalStateException: Can not perform this action after onSaveInstanceState
...rence of the FragmentActivity solved the problem. My code looks as follows now:
public class MyFragmentActivity extends FragmentActivity implements OnFriendAddedListener {
private static WeakReference<MyFragmentActivity> wrActivity = null;
@Override
public void onCreate(Bundle s...
What does O(log n) mean exactly?
...propriate spot in a new, empty phone book.
For the below examples, we're now at the printer's office. Phone books are waiting to be mailed to each resident or business, and there's a sticker on each phone book identifying where it should be mailed to. Every person or business gets one phone book.
...
How to detect when a UIScrollView has finished scrolling
...L)decelerate {
if (!decelerate) {
_isScrolling = NO;
}
}
Now, if your scroll is due to a programmatic setContentOffset/scrollRectVisible (with animated = YES or you obviously know when scroll is ended):
- (void)scrollViewDidEndScrollingAnimation {
_isScrolling = NO;
}
If y...
What is the difference between concurrency, parallelism and asynchronous methods?
...are NOT the same thing.
Differences between concurrency vs. parallelism
Now let’s list down remarkable differences between concurrency and parallelism.
Concurrency is when two tasks can start, run, and complete in overlapping time periods. Parallelism is when tasks literally run at the same ti...
Convert Month Number to Month Name Function in SQL
... datetime value rather than just the month number; to get this to work you now need to 'invent' a date/time value. Think the solution from leoinfo was a bit more relevant
– schizoid04
Jun 4 '18 at 19:51
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