functional-programming

问题 The Control.Arrow.Operations.ArrowCircuit class is for: An arrow type that can be used to interpret synchronous circuits. I want to know what synchronous means here. I looked it up on Wikipedia, where they are speaking of digital electronics. My electronics is quite rusty, so here is the question: what is wrong (if anything is) with such an instance for the so-called asynchronous stream processors: data StreamProcessor a b = Get (a -> StreamProcessor a b) | Put b (StreamProcessor a b) | Halt

问题 I suppose we can use std::transform to replicate the map behavior in C++ like this : std::vector<int> in = { 1 , 2 , 3 ,4 }; std::vector<int> out(in.size()); std::transform(in.being() , in.end() , out.begin() , [](const int & val) { return val+1; }); I guess a better way would be to use the back inserter.' std::vector<int> out2; std::transform(in.begin() , in.end() , std::back_inserter(out2) , [](const int & val){ return val + 1; }); // out will be { 2 , 3 ,4 ,5 } Am I right ? How do I do the

问题 How is IntStream , DoubleStream , or LongStream better than regular stream in Java 8? Do these threads have high performance or maybe usability? 回答1: Stream<Integer> etc. have to work with boxed values ( Integer instead of primitive int ) which takes significantly more memory and usually a lot of boxing/unboxing operations (depending on your code). Why only Int/Double/Long ? Just because they were expected to be used most often. Same applies to OptionalInt and friends and all the functional

问题 How is IntStream , DoubleStream , or LongStream better than regular stream in Java 8? Do these threads have high performance or maybe usability? 回答1: Stream<Integer> etc. have to work with boxed values ( Integer instead of primitive int ) which takes significantly more memory and usually a lot of boxing/unboxing operations (depending on your code). Why only Int/Double/Long ? Just because they were expected to be used most often. Same applies to OptionalInt and friends and all the functional

问题 Trying to level up my Elixir understanding by doing algo/leetCode style problems using Elixir. As I'm a relatively new programmer (around a year in) and was trained on traditionally OOP languages like Ruby and JS, it's still somewhat hard for me to wrap my head around doing algo questions in a functional paradigm, though I felt I understood the Udemy course I took on Elixir/Phoenix. I wrote a solution to the LeetCode "valid anagram" problem using Elixir and Repl and wanted to see if people

问题 Trying to level up my Elixir understanding by doing algo/leetCode style problems using Elixir. As I'm a relatively new programmer (around a year in) and was trained on traditionally OOP languages like Ruby and JS, it's still somewhat hard for me to wrap my head around doing algo questions in a functional paradigm, though I felt I understood the Udemy course I took on Elixir/Phoenix. I wrote a solution to the LeetCode "valid anagram" problem using Elixir and Repl and wanted to see if people

问题 Trying to level up my Elixir understanding by doing algo/leetCode style problems using Elixir. As I'm a relatively new programmer (around a year in) and was trained on traditionally OOP languages like Ruby and JS, it's still somewhat hard for me to wrap my head around doing algo questions in a functional paradigm, though I felt I understood the Udemy course I took on Elixir/Phoenix. I wrote a solution to the LeetCode "valid anagram" problem using Elixir and Repl and wanted to see if people

问题 I'm trying to swap 2 elements within an array in a functional way in javascript (es6) let arr = [1,2,3,4,5,6] let result = swap(arr, 1, 2) // input: array, first element, second element // result=[1,3,2,4,5,6] The only way I could think about is: const swap = (arr, a, b) => arr.map( (curr,i) => i === a ? arr[b] : curr ) .map( (curr,i) => i === b ? arr[a] : curr ) But this code runs twice over the array, and not readable at all. Any suggestions for a nice clean functional code? Thanks. 回答1:

问题 I'm trying to swap 2 elements within an array in a functional way in javascript (es6) let arr = [1,2,3,4,5,6] let result = swap(arr, 1, 2) // input: array, first element, second element // result=[1,3,2,4,5,6] The only way I could think about is: const swap = (arr, a, b) => arr.map( (curr,i) => i === a ? arr[b] : curr ) .map( (curr,i) => i === b ? arr[a] : curr ) But this code runs twice over the array, and not readable at all. Any suggestions for a nice clean functional code? Thanks. 回答1:

问题 I'm trying to swap 2 elements within an array in a functional way in javascript (es6) let arr = [1,2,3,4,5,6] let result = swap(arr, 1, 2) // input: array, first element, second element // result=[1,3,2,4,5,6] The only way I could think about is: const swap = (arr, a, b) => arr.map( (curr,i) => i === a ? arr[b] : curr ) .map( (curr,i) => i === b ? arr[a] : curr ) But this code runs twice over the array, and not readable at all. Any suggestions for a nice clean functional code? Thanks. 回答1: