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Finding the type of an object in C++
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dynamic_cast should do the trick
TYPE& dynamic_cast<TYPE&> (object);
TYPE* dynamic_cast<TYPE*> (object);
The dynamic_cast keyword casts a datum from one pointer or reference type to another, performing a runtime...
What is the purpose of Flask's context stacks?
...backend". In other words, the Flask(...) application constructor has been called twice, creating two instances of a Flask application.
Contexts
When you are working with Flask, you often end up using global variables to access various functionality. For example, you probably have code that reads.....
How do I use itertools.groupby()?
I haven't been able to find an understandable explanation of how to actually use Python's itertools.groupby() function. What I'm trying to do is this:
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Defining a variable with or without export
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Specifically export makes the variable available to child processes via the environment.
– Beano
Jul 21 '09 at 13:35
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Call a python function from jinja2
I am using jinja2, and I want to call a python function as a helper, using a similar syntax as if I were calling a macro. jinja2 seems intent on preventing me from making a function call, and insists I repeat myself by copying the function into a template as a macro.
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Rank function in MySQL
... (SELECT @curRank := 0) r
ORDER BY age;
The (SELECT @curRank := 0) part allows the variable initialization without requiring a separate SET command.
Test case:
CREATE TABLE person (id int, first_name varchar(20), age int, gender char(1));
INSERT INTO person VALUES (1, 'Bob', 25, 'M');
INSERT I...
What is the best way to concatenate two vectors?
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AB.reserve( A.size() + B.size() ); // preallocate memory
AB.insert( AB.end(), A.begin(), A.end() );
AB.insert( AB.end(), B.begin(), B.end() );
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Google Maps API 3 - Custom marker color for default (dot) marker
...s of other questions similar to this ( here , here and here ), but they all have accepted answers that don't solve my problem. The best solution I have found to the problem is the StyledMarker library, which does let you define custom colours for markers, but I can't get it to use the default m...
What differences, if any, between C++03 and C++11 can be detected at run-time?
...onstrate breaking changes. The following is a tweaked testcase, which initially was used to demonstrate such a change, but now is used to test for C++0x or C++03.
struct X { };
struct Y { X x1, x2; };
struct A { static X B(int); };
typedef A B;
struct C : A {
using ::B::B; // (inheriting const...
How can I profile Python code line-by-line?
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can anyone show how to actually use this library? The readme teaches how to install, and answers various FAQs, but doesn't mention how to use it after a pip install..
– cryanbhu
Jul 25 '18 at 3:28
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