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Grouping functions (tapply, by, aggregate) and the *apply family
...ed by the extremely popular plyr package, the base functions remain useful and worth knowing.
This answer is intended to act as a sort of signpost for new useRs to help direct them to the correct *apply function for their particular problem. Note, this is not intended to simply regurgitate or repla...
What is The Rule of Three?
...antics.
This means that objects are implicitly copied in various contexts,
and we should understand what "copying an object" actually means.
Let us consider a simple example:
class person
{
std::string name;
int age;
public:
person(const std::string& name, int age) : name(name), ag...
Returning a boolean from a Bash function
... want to write a bash function that check if a file has certain properties and returns true or false. Then I can use it in my scripts in the "if". But what should I return?
...
Which characters are valid in CSS class names/selectors?
...racter is a hyphen, the second character must2 be a letter or underscore, and the name must be at least 2 characters long.
-?[_a-zA-Z]+[_a-zA-Z0-9-]*
In short, the previous rule translates to the following, extracted from the W3C spec.:
In CSS, identifiers (including element names, classes, ...
What are the differences between BDD frameworks for Java? [closed]
What are the pros and cons of each Behavior Driven Development (BDD) framework for Java?
8 Answers
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What is the difference between “long”, “long long”, “long int”, and “long long int” in C++?
I am transitioning from Java to C++ and have some questions about the long data type. In Java, to hold an integer greater than 2 32 , you would simply write long x; . However, in C++, it seems that long is both a data type and a modifier.
...
Error during installing HAXM, VT-X not working
I am an entry-level Android software developer. I recently heard about HAXM that support emulator in rendering graphics more smoothly. I downloaded appropriate file HAXM file for Windows 7 64 bit, unpacked and started installing. However, during the installation process I get this error:
...
java.lang.UnsupportedClassVersionError: Bad version number in .class file?
... suggestions on the web indicate that the code was compiled in one version and executed in another version (new on old). However, I only have one version of JRE on my system. If I run the commands:
...
Why doesn't 'ref' and 'out' support polymorphism?
...
UPDATE: I used this answer as the basis for this blog entry:
Why do ref and out parameters not allow type variation?
See the blog page for more commentary on this issue. Thanks for the great question.
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Let's suppose you have classes Animal, Mammal, Reptile, Giraffe, Turtle and Ti...
Convert Existing Eclipse Project to Maven Project
...ilds. Right now the procedure is far more complicated than it ought to be, and we're hoping that Maven will simplify things to a one-click build.
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