Functional programming is a paradigm which attempts to solve computational problems by the chained evaluation of functions whose output is determined by their inputs rather than the program state. In this style of programming, side effects and mutable data are deprecated.

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F# sudoku game logic

I am trying to create a sudoku game in f# and I'm having a bit of trouble with the file reading and writing. But since I've also just started programming in f# I would like to check if my thinking is ...
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31 views

Idiomatic exception handling for socket connection [migrated]

I'm trying to understand how I can elegantly use scala.util.control.Exception package. To be more specific I want to convert this piece of Java code to functional ...
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1answer
97 views

Functional programming in Python: 2048 merge functions

I've written the core functions for a basic 2048 game. I know Python isn't a functional programming language, but I like the "functional style" (easier to maintain, simple to understand, more ...
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28 views

Factory for arbitrarily high-order operations

Grade 0: ++ This is so low that it is boring; the operation of grade 0 is incrementing or counting up, for example: ...
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12 views

How to feed data Excel file from C# language that can be retrieved? [closed]

Guys I need to get the code to to insert data from C# to excel file that already connected;for the application sending sms from desktop to cell phone by invoking info from excel file which already ...
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24 views

Selecting subset of size k using recursion

Sometimes I need to implement recursive algorithms that pass a certain state from one recursive call to another. For example, a greedy subset selection: we have a set of candidate objects, and we ...
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1answer
57 views

Detecting cycles in a directed graph without using mutable sets of nodes

I recently came across the classic algorithm for detecting cycles in a directed graph using recursive DFS. This implementation makes use of a stack to track nodes currently being visited and an extra ...
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1answer
37 views

Currying in matlab

As MATLAB has a hard maximum of 10 input arguments it's possible, but ugly, to implement a curry function in this manner: ...
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27 views

Hunt the wumpus: Functional JavaScript (Node) with Lodash

I'd like a code review of the following simple implementation of the classic game Hunt the Wumpus I'm trying to use JavaScript in the most "functional" way. To help me, I'm using lodash and ES6. ...
6
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58 views

Higher-order Prolog predicates combine/3 and reduce/3

I'm trying to find useful versatile meta-predicates that are different from the vanilla ones offered currently by library(apply). How about the following two: ...
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2answers
31 views

Tail-Recursion to get a Map of word counts

I want to read a file and store the number of occurrences of each word in a Map, using tail recursion. I came up with the following; it seems to work; does it look like it's right? ...
4
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1answer
56 views

Continuable if error is null

I made a method that I can use to avoid having to handle errors from callbacks. What it does is, call the passed method only if the first argument is null. So essentially it will bypass to the last ...
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1answer
34 views

L system equations

This is my first program on my second try to learn haskell :) ...
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2answers
55 views
3
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1answer
55 views

Hackerrank, Service Lane in Haskell

Problem statement Calvin is driving his favorite vehicle on the 101 freeway. He notices that the check engine light of his vehicle is on, and he wants to service it immediately to avoid any ...
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3answers
78 views

Minimum element in a tuple

I'm solving exercise 2 from lecture 3 of Berkeley's CS 61A (2012): Write a function min_element that returns the minimum element in a tuple. ...
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2answers
98 views

Transforming an array in Ruby

I watched a presentation by Dave Thomas on Elixir where he gave an example problem that he solved using functional programming. He mentioned using Ruby to solve the same problem, but did not show an ...
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1answer
79 views

Small console app to execute some remote scripts

I'm learning F# and functional programming, from a background in C# and imperative/OOP. I've ported a small, one-off console app from C# to F#. The port worked (the app behaves the same way), but I'd ...
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1answer
20 views

Matlab quadractic function with graph

I'm very new to MatLab and I am having some difficulty creating the code and just understanding what to put where. I got my quadratic formula to run and loop(Ex 4.2), but now I've been asked to have a ...
2
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2answers
101 views

Sequence processing problems

Problem 1: Sum the even numbers for the first n fibonacci numbers Solution: ...
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0answers
26 views

Functional, Loaner-Like Pattern For Consuming SQS Queues, Deleting Queue Items On Success

My program fetches input from a RabbitMQ or Amazaon SQS-like queue. There is not always input available in the queue. If a message is available, it triggers work. If that work is successful, ...
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1answer
52 views

Random Plinko path using functional programming style

In order to learn both scala and functional programming, I've been rewriting the projects from my introductory CS class in scala. One of the projects was a plinko game, where the user picks a slot to ...
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2answers
47 views

Checking in four directions for board game win

I have the following code which I would like to simplify in Haskell, although I'm not sure how. I recall that I can use monads to simplify a case chain when the result of the case leads onto a next ...
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2answers
116 views

Converting imperative style user input menu to functional programming style

I am currently trying to teach myself scala by rewriting projects from my intro CS class, which was taught in C++. In addition to just learning the syntax I am trying to gain understanding of how ...
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2answers
461 views

Printing removed items using lambdas and streams

I'm struggling to make my lambdas readable. I've seen various approaches. Below are three different examples that all do the same thing. Forgive the example: I suspect there are better actual ...
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2answers
82 views

“Invert” a JavaScript object hash whose values are arrays to produce a new object hash with keys as the elements of those original value vectors

Background lodash and underscore have an invert function that takes an object hash and converts it to a new one, which has keys as the input object's values and ...
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20 views

Multitenant Cassandra Query in Clojure

The following code handles querying for user data in a multitenant Cassandra database. Each tenant has their own keyspace and within that keyspace data about each tenants users is stored. This code ...
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1answer
75 views

Streaming Collatz

Challenge The recent question The 3n + 1 algorithm for a range inspired me to investigate a Java-8 dependent streaming mechanism for solving the programming challenge: For any two numbers ...
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1answer
37 views

Performance of parsing math functions

I wrote the following code as part of a larger application. This code takes a string that defines a mathematical function on such as r,y x[0], x[1] etc. or any ...
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1answer
136 views

Abstracting the process of finding the index of the maximum in Python

Suppose I want to find the index of the maximal value of a given sequence. In Matlab, this is: [value, index] = max(x) In Python, I would abstract the following ...
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2answers
55 views

2D lattice random walk plots in functional style

To practice writing code in the functional programming style, I wrote a program to plot two-dimensional lattice random walks. I'd appreciate any feedback about how to improve its "functionaliness". ...
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1answer
90 views

“Data Abstraction” and “Abstract Data Type” for a rational number [closed]

Below is implementation 1 of data abstraction for rational number using functional paradigm written in Python: ...
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3answers
134 views

Optimization of stack frame usage with recursion

For the given below exercise: Here is one method to check if a number is prime: ...
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2answers
67 views

Function returning higher order function

For the below given exercise: Define a function cycle which takes in three functions as arguments: f1, f2, f3. cycle will then return another function. The returned fuction should take in an ...
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1answer
55 views

File-to-fully qualified class name function

My instincts are telling me a seasoned Scala programmer will find my code less than optimal. As will no doubt be obvious, I'm a Java guy who has just started in with Scala. Is there a more ...
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1answer
102 views

Extracting tuples from Excel sheet

My code have too much nested option processing which makes it ugly. But it has an advantage it has no side effect and typesafe. ...
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3answers
69 views

Prime factorization of an integer

I have just started learning functional programming (Haskell) for fun after using imperative languages my whole life. I am looking for quick and simple tips from pros on how the particular code I just ...
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2answers
81 views

Test runner for Scala problems

I'm learning Scala and could use another set of eyes on the code below. I'm creating a test runner for the 99 scala problems set. I figure between actually solving the problems and working through the ...
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2answers
392 views

Failing fast by raising an exception with a custom message

This is a script that utilizes lazy exception throwing. What I do is decorate a function that might throw an exception to throw an exception with a formatted string. ...
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50 views

Using interface for generated functions or just create plain functions

I was wondering which code might be better. I'm abstracting away the rote code as follows: ...
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3answers
173 views

Functional programming approach to repeated function application

Control like if..else and while If \$f\$ is a numerical function and \$n\$ is a positive integer, then we can form the ...
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2answers
81 views

Summation and product functions using functional paradigm

Below is the problem: Show that both summation and product are instances of a more general function, called accumulate, with the following signature: ...
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2answers
68 views

Functional-style linked list written in C

For my Operating Systems class, I needed a linked list data structure and didn't have one already written. During the course of thinking about how to implement a linked list again (it had been a ...
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1answer
139 views

Counting Lines and Sum of Lines

I have a small function that when passed a str that names a file that contains a program; it returns a 2-tuple with the number of the non-empty lines in that program, and the sum of the lengths of all ...
3
votes
1answer
53 views

UpdateGame function for Tetris

I am writing a Tetris game while learning Haskell and I'm trying to make the following code more concise and easier to read. How can I improve it? Note that the function is not finished yet (There is ...
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0answers
79 views

Natural sorting/comparing algorithm in TypeScript

This code sorts string that may contain numbers in natural order, that's it, "item 2" comes before than "item 10". It currently ignores case. I plan to implement options to handle case sensitivity and ...
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4answers
260 views

Hailstone Sequences in Python

For the problem given: Douglas Hofstadter’s Pulitzer-prize-winning book, Gödel, Escher, Bach, poses the following mathematical puzzle. Pick a positive integer \$n\$ as the start. If \$n\$ ...
5
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1answer
65 views

Lightweight TicTacToe in F#

This is more of a 'model' of TicTacToe, as you'll see it's not "gameified" in the sense that it will allow for inputs and outputs nor will it record any "active" state of the game but those things are ...
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3answers
248 views

Print “n” number of “hello world”

I had come up with the following code: ...
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2answers
159 views

N-Queens functional

I'm trying to get a better grip on the new functional possibilities of Java 8. As an example, I took this very elegant Haskell snippet: ...