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data.table vs dplyr: can one do something well the other can't or does poorly?
...ese aspects to provide a comprehensive answer/comparison (in no particular order of importance): Speed, Memory usage, Syntax and Features.
My intent is to cover each one of these as clearly as possible from data.table perspective.
Note: unless explicitly mentioned otherwise, by referring to dpl...
Why would a static nested interface be used in Java?
...
An inner interface has to be static in order to be accessed. The interface isn't associated with instances of the class, but with the class itself, so it would be accessed with Foo.Bar, like so:
public class Baz implements Foo.Bar {
...
}
In most ways, this ...
What does the question mark operator mean in Ruby?
...ruby 1.9:
"F".ord
Also notice that ?F will return the string "F", so in order to make the code shorter, you can also use ?F.ord in Ruby 1.9 to get the same result as "F".ord.
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What is the difference between LL and LR parsing?
...ponds to Reverse Polish Notation. The difference between PN and RPN is the order of traversing the binary tree of the equation:
+ 1 * 2 3 // Polish (prefix) expression; pre-order traversal.
1 2 3 * + // Reverse Polish (postfix) expression; post-order traversal.
According to Haberman, this ill...
Storing money in a decimal column - what precision and scale?
...However, rather than a one-size-fits-all approach, some research may be in order. Ask your designer or domain expert about accounting rules which may be applicable: GAAP, EU, etc. I vaguely recall some EU intra-state transfers with explicit rules for rounding to five decimal places, therefore using ...
How to fix “Headers already sent” error in PHP
...
Unintentional:
Whitespace before <?php or after ?>
The UTF-8 Byte Order Mark specifically
Previous error messages or notices
Intentional:
print, echo and other functions producing output
Raw <html> sections prior <?php code.
Why does it happen?
To understand why header...
python max function using 'key' and lambda expression
...t-2-0ce0a02693e4>", line 1, in <module>
max(lis)
TypeError: unorderable types: int() > str()
But this works, as we are comparing integer version of each object:
>>> max(lis, key=lambda x: int(x)) # or simply `max(lis, key=int)`
'111'
...
Where are my postgres *.conf files?
...tart)
# - When to Log -
#client_min_messages = notice # values in order of decreasing detail:
# debug5
# debug4
# debug3
# debug2
# debug1
# log
...
When should I use the Visitor Design Pattern? [closed]
...virtual void hereIsACat(Cat *c) = 0;
};
Then, we modify the hierarchy in order to accept new operations:
class Animal
{ public: virtual void letsDo(Operation *v) = 0; };
class Dog : public Animal
{ public: void letsDo(Operation *v); };
void Dog::letsDo(Operation *v)
{ v->hereIsADog(this); }
...
Sorting a list using Lambda/Linq to objects
...n direction)
{
if (direction == SortDirection.Ascending)
list = list.OrderBy(sorter);
else
list = list.OrderByDescending(sorter);
}
Now you can specify the field to sort when calling the Sort method.
Sort(ref employees, e => e.DOB, SortDirection.Descending);
...