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E11000 duplicate key error index in mongodb mongoose
... the sparse index to filter these null values from the unique index and avoid the error.
unique indexes
Sparse indexes only contain entries for documents that have the indexed field, even if the index field contains a null value.
In other words, a sparse index is ok with multiple documents all ha...
Auto column width in EPPlus
...s[Worksheet.Dimension.Address].AutoFitColumns();
Please note you need to call this method after filling the worksheet.
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How Drupal works? [closed]
...ry content" of the page.
Once the primary page content is built, index.php calls theme('page', $content), which hands off the content to Drupal's theming/skinning system. There, it's wrapped in sidebars/headers/widgets/etc..
The rendered page is then handed back to apache and it gets sent back to th...
Properly removing an Integer from a List
...
Java always calls the method that best suits your argument. Auto boxing and implicit upcasting is only performed if there's no method which can be called without casting / auto boxing.
The List interface specifies two remove methods (pl...
Is errno thread-safe?
...nt errno; so my question is, is it safe to check errno value after some calls or use perror() in multi-threaded code. Is this a thread safe variable? If not, then whats the alternative ?
...
do N times (declarative syntax)
... based on Array.forEach, without any library, just native vanilla.
To basically call something() 3 times, use:
[1,2,3].forEach(function(i) {
something();
});
considering the following function:
function something(){ console.log('something') }
The outpout will be
something
something
someth...
method overloading vs optional parameter in C# 4.0 [duplicate]
... the number of parameters.
For example say you want a method foo to be be called/used like so, foo(), foo(1), foo(1,2), foo(1,2, "hello"). With method overloading you would implement the solution like this,
///Base foo method
public void DoFoo(int a, long b, string c)
{
//Do something
}
/// ...
Cmake vs make sample codes?
...at is the input and output.
The CMakeLists.txt contains list of function-calls that are defined by cmake.
(CMake function) Vs Make rules
In Makefile the rules and recipes are used instead of functions . In addition to function-like feature, rules and recipes provide chaining. My minimalistic Ma...
How to use R's ellipsis feature when writing your own function?
...me.
For use of unevaluated ... argument look at write.csv code where match.call is used.
As you write in comment result in Dirk answer is not a list of lists. Is a list of length 4, which elements are language type. First object is a symbol - list, second is expression 1:10 and so on. That explain w...
Why do we need extern “C”{ #include } in C++?
...ty, C++'s ABI generally 'mangles' the names of their functions/methods, so calling printf() without flagging the prototype as a C function, the C++ will actually generate code calling _Zprintf, plus extra crap at the end.)
So: use extern "C" {...} when including a c header—it's that simple. Other...