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How to properly check if std::function is empty in C++11?
...tional/function/operator_bool/
Example
// function::operator bool example
#include <iostream> // std::cout
#include <functional> // std::function, std::plus
int main () {
std::function<int(int,int)> foo,bar;
foo = std::plus<int>();
foo.swap(bar);
std::cout &l...
How do I tell Maven to use the latest version of a dependency?
...files. Forms
one half of the built-in "Poor Man's
SCM".
Just thought I'd include it for any future reference.
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data.table vs dplyr: can one do something well the other can't or does poorly?
...aster than dplyr as the number of groups and/or rows to group by increase, including benchmarks by Matt on grouping from 10 million to 2 billion rows (100GB in RAM) on 100 - 10 million groups and varying grouping columns, which also compares pandas. See also updated benchmarks, which include Spark a...
What exactly is metaprogramming?
...metaprogramming was LISt Processor (LISP) language in late 1950s. LISP 1.5 included a number of features that made metaprogramming easier. Firstly, LISP's core data type is nested lists, i.e. trees like (a (b c) d), which means any LISP code can expressed natively as a data structure. This is known ...
Tricky Google interview question
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@GaBorgulya Yes, it includes five times the list [1, 2, 4, 5,...] so it includes 5*4.
– Thomas Ahle
Sep 14 '12 at 1:50
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Accessing class variables from a list comprehension in the class definition
...the class block; it does not extend to the code blocks of methods – this includes comprehensions and generator expressions since they are implemented using a function scope. This means that the following will fail:
class A:
a = 42
b = list(a + i for i in range(10))
So, to summarize: ...
Parsing JSON from XmlHttpRequest.responseJSON
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I think you have to include jQuery to use responseJSON.
Without jQuery, you could try with responseText and try like eval("("+req.responseText+")");
UPDATE:Please read the comment regarding eval, you can test with eval, but don't use it in wor...
setting an environment variable in virtualenv
...ms that .env files bork Heroku builds, at least in my experience. So don't include it in your repo. Long time user / huge fan of autoenv btw. Hi Kenneth, you da man!
– galarant
Jan 29 '15 at 0:42
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Clear Application's Data Programmatically
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Take care ! You remove everyting in the app folder, including share preferences.. not only the cache dir itself and its content.
– Snicolas
May 22 '13 at 13:44
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