case_when in mutate pipe

As of version 0.7.0 of dplyr, case_when works within mutate as follows: For more information: http://dplyr.tidyverse.org/reference/case_when.html

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Time complexity of a Priority Queue in C++

If you have an array of size n and you want to build a heap from all items at once, Floyd’s algorithm can do it with O(n) complexity. See Building a heap. This corresponds to the std::priority_queue constructors that accept a container parameter. If you have an empty priority queue to which you want to add n items, one at a time, … Read more

Does a Java to C++ converter/tool exist?

It’s possible to do anything given enough time, money and resources. Is it practical? Beyond trivial examples not really. Or rather it depends on what constitutes an acceptable error rate. The real problem is that the idioms are different in Java to C++. Java to C# for example would actually be far easier (because the … Read more

Dice rolling simulator in Python

Let’s walk through the process: You already know what you need to generate random numbers. import random (or you could be more specific and say from random import randint, because we only need randint in this program) As you’ve already said it; print(“You rolled”,random.randint(1,6)) “rolls the dice”. but it does it only once, so you need a loop to repeat it. … Read more

What is EOF in the C programming language?

On Linux systems and OS X, the character to input to cause an EOF is Ctrl–D. For Windows, it’s Ctrl–Z. Depending on the operating system, this character will only work if it’s the first character on a line, i.e. the first character after an Enter. Since console input is often line-oriented, the system may also not recognize the … Read more

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