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Explanation of JSONB introduced by PostgreSQL
...imple explanation of the difference between json and jsonb (original image by PostgresProfessional):
SELECT '{"c":0, "a":2,"a":1}'::json, '{"c":0, "a":2,"a":1}'::jsonb;
json | jsonb
------------------------+---------------------
{"c":0, "a":2,"a":1} | {"a": 1, "c...
Which C++ idioms are deprecated in C++11?
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At one point in time it was argued that one should return by const value instead of just by value:
const A foo();
^^^^^
This was mostly harmless in C++98/03, and may have even caught a few bugs that looked like:
foo() = a;
But returning by const is contraindicated in C++11 bec...
Is there a replacement for unistd.h for Windows (Visual C)?
...lib\gcc\mingw32\4.6.2\include\ssp
Here is the code for the MinGW version, by Rob Savoye; modified by Earnie Boyd, Danny Smith, Ramiro Polla, Gregory McGarry and Keith Marshall:
/*
* unistd.h
*
* Standard header file declaring MinGW's POSIX compatibility features.
*
* $Id: unistd.h,v c3ebd36f8...
What does the slash mean in help() output?
...he C API.
It means the key argument to __contains__ can only be passed in by position (range(5).__contains__(3)), not as a keyword argument (range(5).__contains__(key=3)), something you can do with positional arguments in pure-python functions.
Also see the Argument Clinic documentation:
To ma...
How can I see the SQL generated by Sequelize.js?
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You can also take advantage of Sequelize's use of the Debug module, by setting your environment, thus:
DEBUG=sequelize:sql*
before starting your app.
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How can I get the max (or min) value in a vector?
... you have assumed input to be vector<double> or does *max_element() by default return double val.
– Samir Kape
May 30 at 11:44
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Multiline bash commands in makefile
... \
gcc $$all
But if you just want to take the whole list returned by the find invocation and pass it to gcc, you actually don't necessarily need a multiline command:
foo:
gcc `find`
Or, using a more shell-conventional $(command) approach (notice the $ escaping though):
foo:
gcc ...
Is there a reason for C#'s reuse of the variable in a foreach?
... naively believe it to be correct. Hopefully the number of people affected by such a scenario is small.
– Eric Lippert
Jan 19 '12 at 14:20
30
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Open a URL in a new tab (and not a new window)
...target-new, but the specification was abandoned.
The reverse is not true; by specifying dimensions for the window in the third argument of window.open(), you can trigger a new window when the preference is for tabs.
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Only variables should be passed by reference
...tension = end($parts);
The reason is that the argument for end is passed by reference, since end modifies the array by advancing its internal pointer to the final element. If you're not passing a variable in, there's nothing for a reference to point to.
See end in the PHP manual for more info.
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