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Aggregate / summarize multiple variables per group (e.g. sum, mean)
... The recast function (also from reshape2) integrates the melt and dcast function in one go for tasks like this: recast(df1, year + month ~ variable, sum, id.var = c("date", "year", "month"))
– Jaap
May 13 '16 at 6:17
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What is the best way to implement constants in Java? [closed]
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That is perfectly acceptable, probably even the standard.
(public/private) static final TYPE NAME = VALUE;
where TYPE is the type, NAME is the name in all caps with underscores for spaces, and VALUE is the constant value;
I highly recommend NOT putting your constants in ...
Polymorphism vs Overriding vs Overloading
...is not definable for Humans. It is only definable for the subclasses Male and Female. Also, Human is an abstract concept — You cannot create a human that is neither Male nor Female. It’s got to be one or the other.
So we defer the implementation by using the abstract class.
public class Mal...
ICollection Vs List in Entity Framework
...ntity Framework applications. I really didn't read that much documentation and I feel like I am suffering for it now.
4 Ans...
Strange out of memory issue while loading an image to a Bitmap object
...n returns from the activity back to the listview activity to the result handler to relaunch my new activity which is nothing more than an image widget.
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DISTINCT for only one column
...OM Products
WHERE ProductModel = 2
AND ProductName LIKE 'CYBER%'
) a
WHERE rn = 1
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Running multiple TeamCity Agents on the same computer?
..., each running a single TeamCity build agent. Each machine is very strong, and we'd like to run several build agents on the same machine.
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Test if a property is available on a dynamic variable
...trying to access it, unless you re-implemented the way dynamic binding is handled in the C# compiler. Which would probably include a lot of guessing, because it is implementation-defined, according to the C# specification.
So you should actually try to access the member and catch an exception, if i...
How to save the output of a console.log(object) to a file?
...ng JSON.stringify(object) , but it doesn't go down on the whole structure and hierarchy.
9 Answers
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How to exclude file only from root folder in Git
...me files being added, but I have several config.php files in source tree and I need to exclude only one, located in the root while other keep under revision control.
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