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Overloading Macro on Number of Arguments
...e these macros:
FOO(World, !) # expands to FOO2(World, !)
FOO(foo,bar,baz) # expands to FOO3(foo,bar,baz)
If you want a fourth one:
#define GET_MACRO(_1,_2,_3,_4,NAME,...) NAME
#define FOO(...) GET_MACRO(__VA_ARGS__, FOO4, FOO3, FOO2)(__VA_ARGS__)
FOO(a,b,c,d) # expeands t...
Can virtual functions have default parameters?
If I declare a base class (or interface class) and specify a default value for one or more of its parameters, do the derived classes have to specify the same defaults and if not, which defaults will manifest in the derived classes?
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Remove duplicated rows
...frame to the columns you need, then use the unique function :D
# in the above example, you only need the first three columns
deduped.data <- unique( yourdata[ , 1:3 ] )
# the fourth column no longer 'distinguishes' them,
# so they're duplicates and thrown out.
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MySQL - Rows to Columns
I tried to search posts, but I only found solutions for SQL Server/Access. I need a solution in MySQL (5.X).
12 Answers
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In pure functional languages, is there an algorithm to get the inverse function?
... is there an algorithm to get the inverse of a function, (edit) when it is bijective? And is there a specific way to program your function so it is?
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ASP.NET Identity DbContext confusion
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I would use a single Context class inheriting from IdentityDbContext.
This way you can have the context be aware of any relations between your classes and the IdentityUser and Roles of the IdentityDbContext.
There is very little overhead in the IdentityDbContext, it is basically a reg...
Why does direction of index matter in MongoDB?
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MongoDB concatenates the compound key in some way and uses it as the key in a BTree.
When finding single items - The order of the nodes in the tree is irrelevant.
If you are returning a range of nodes - The elements close to eac...
How to set timer in android?
...ok since this isn't cleared up yet there are 3 simple ways to handle this.
Below is an example showing all 3 and at the bottom is an example showing just the method I believe is preferable. Also remember to clean up your tasks in onPause, saving state if necessary.
import java.util.Timer;
import...
Javascript How to define multiple variables on a single line?
...line, I'm getting confused how to properly define multiple JavaScript variables on a single line.
7 Answers
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Why does ('0' ? 'a' : 'b') behave different than ('0' == true ? 'a' : 'b') [duplicate]
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First, for completeness:
('0' ? 'a' : 'b')
is 'a', because '0' is a non-empty string, which always evaluates to true:
String: The result is false if the argument is the empty String (its length is zero);
otherwise the result is true.
Now to '0' == tru...