I have a data frame containing a factor . When I create a subset of this dataframe using subset or another indexing function, a new data frame is created. However, the factor variable retains all of its original levels, even when/if they do not exist in the new dataframe. ...

Say I have a list of n elements, I know there are n! possible ways to order these elements. What is an algorithm to generate all possible orderings of this list? Example, I have list [a, b, c]. The algorithm would return [[a, b, c], [a, c, b,], [b, a, c], [b, c, a], [c, a, b], [c, b, a]]. ...

I recently heard the term "hook" while talking to some people about a program I was writing. I'm unsure exactly what this term implies although I inferred from the conversation that a hook is a type of function. I searched for a definition but was unable to find a good answer. Would someone be ab...

I am very new to RoR and I want to select between APS.NET MVC3 and RoR. C# is sure easier for me as I have been doing it for so long but I am wondering if there is any point to consider using RoR over .MVC to develop a real world website? ...

What is the difference between the following class methods? 13 Answers 13 ...

I've just done my first little webapp in django and I love it. I'm about to start on converting an old production PHP site into django and as part its template, there is a navigation bar. ...

Upcasting is allowed in Java, however downcasting gives a compile error. 11 Answers 1...

My Google-fu has failed me. 14 Answers 14 ...

EDIT: As of Java 8, static methods are now allowed in interfaces. 24 Answers 24 ...

I need a way to compare multiple strings to a test string and return the string that closely resembles it: 12 Answers ...