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Questions tagged [functional-programming]

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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84 views

Solving Knight's Travails Problem without using vector for position

I'm trying to implement a solution to the The Odin Project - Project 2: Knight’s Travails in Clojure (Functional Programming) based on the solution posted by benjdelt. I would like to know your ...
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47 views

Time travelling through state history with persistent consequences

I am working on a game written in Kotlin that has a state management system similar to Redux. The state of the game is kept in a single place and is represented as immutable data classes (no logic). ...
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1answer
114 views

Combinatoric problem in Haskell

I am new to functional programming. Just now I solved my first "real world" task using Haskell and now I'm wondering whether I got it "right" and what can be improved. The problem arises from tensor ...
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1answer
265 views

Quadratic Equation Solver v2.0 in Javascript using Functional Programming

I have posted this in continuation to my earlier post Quadratic equation solver in JavaScript. Tried to improve on the shortcomings last time and also changed the logic. It is still not covering all ...
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2answers
76 views

Processing a list of pairs of items using promises and functional programming

I posted an answer on StackOverflow which I believed to be adherent to the principles of Functional Programming. However, I was told by the original asker that it was not 'functional' as my function ...
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233 views

Recursive solution for Longest Substring Without Repeating Characters written in Elixir

Here's my recursive implementation of a sliding window algorithm to find the longest substring of a given string without repeating characters. Is there a more idiomatic-Elixir way to write this? <...
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1answer
87 views

Transforming data from an API using Typescript and Lodash

As a front-end developer, I am given the following result from an API, an array of objects that looks like: ...
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1answer
87 views

Is It In Its Prime?

Just because I'm bored, I wrote yet another prime number generator. I think it's pretty clean, but I won't be surprised if someone finds something to comment on. ...
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34 views

Javascript RPC Call Handles Data and Returns DB Response

I have a service within a larger set of microservices that's handling a RPC call. My function mainly just parses through the request, uses the data to insert data into our MongoDB database, and then ...
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73 views

Extending functions to tuples

Intro: Imagine you have defined addition on types A and B with function A add(A,A) and <...
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1answer
58 views

Create a collection of functions tupled with a collection of parameters, and execute the collection in order in Scala

I am trying to create a collection of Unit functions that have any arity and type, and will execute them in order. This is the working implementation that I have: ...
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1answer
205 views

Check Is Anagram Scala HashMap based implementation

Here is the HashMap based implementation of the function checking whether two strings are anagrams: Example: ...
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57 views

Pure functional code for the sublists of a list

The code below gives me the list of sublists of a list. Code can still be improved to avoid the use of append, right? ...
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2answers
170 views

Lorentz Attractor visualization using functional programming

I have been working on this Lorenz Attractor visualization for the past day. I am currently also trying to change my coding style into a more functional programming one. I find it quite hard, to be ...
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3answers
53 views

Collecting a list of documents from a factory for an AngularJS controller

With this controller I'm injecting myFactory and using Array.push() to add the array ...
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1answer
47 views

Inspectors & Deconstruction on Unions in a list

I am still new to functional programming and found myself trying to filter and map a list of discriminating unions. I could be wrong, but it started to feel very unnatural to do this. I just couldn'...
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1answer
42 views

Storing facts for logical questions

I am writing a crude artificial intelligence program. I am happy with my program's ability to file away new word in ways that will allow logic to be done on them. Before I start expanding the logic ...
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1answer
340 views

Scala tic-tac-toe no mutable state

The following was an exercise for me to try to understand how state can be passed down the stack without immutability. I'm used to writing java code and this is just a way for me to understand. I've ...
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0answers
89 views

Deep filter value using functional programming principles

deepFilter function uses a predicate to filter properties which may be nested deeply in the given ...
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1answer
25k views

Passing a generic function as parameter

Ran into this idea and I'm curious if it's possible. I'm trying to make a single function that can test ALL of my sorting algorithms dynamically. I want to be able to pass the sorting function as a ...
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1answer
208 views

Equation parser + solver

Here is an equation parser that I just wrote. My focus was on readability and the prospect of adding new features in the future. Since I like a somewhat functional style, I also gave type annotations, ...
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1answer
55 views

Update the idx values if vals element match between consecutive rows

I want to update the numbers in idx field if there is any matching letter between the vals from two consecutive row. ...
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2answers
293 views

Implementation of Permutation Algorithm A from Topor, 1982

This is Algorithm A from Functional Programs for Generating Permutations (Topor, 1982). The author states that the algorithm was described in TAoCP Vol 1. We have implemented Algorithm A in F# as ...
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2answers
191 views

Porting functional programming code to Linq

I am very new to C# programming, so for practice I thought I would try to port a simple haskell function over to Linq. From learn you a haskell, there is the following implementation of powerset: <...
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3answers
260 views

Eloquent Javascript exercise: find average age from ancestors array per century

I solved an exercise from the book "Eloquent Javascript". I want to share with you guys the solution. The exercise is from chapter 5. Summing up, I have to find the average age from the ancestors ...
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86 views

Immutable Queue with Bulk-Enqueue

I recently needed a data structure with FIFO queue semantics that supported efficient bulk-insertion (often need to enqueue thousands of messages at once). I took a look at Purely Functional Data ...
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131 views

Advent of Code 2017 Day 6 (part 2) in Functional Programming (FP)

I wanted to practice functional programming (FP) without using any library but using vanilla JS only. So I took a problem from Advent of Code (the 2nd part of Day 6). You can only access the 2nd part ...
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1answer
250 views

Voting plugin for an IRC bot

MetaBrainz has an IRC channel called #metabrainz on which there's a bot called BrainzBot running. It provides utilities such as linking to JIRA issues or Github PRs ...
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1answer
355 views

Count the number of digits in an integer using F# and log10

This code counts the number of digits in an integer. let digitCount number = (int) (log10 ((float)number)) + 1; For instance, it tells us ...
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1answer
141 views

Advent of Code 2017 Day 6 (part 1) in Functional Programming (FP)

I wanted to practice functional programming (FP) without using any library but using vanilla JS only. So I took a problem from Advent of Code (the 1st part of Day 6): http://adventofcode.com/2017/day/...
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0answers
53 views

Advent of Code 2017 Day 5 (part 2) in Functional Programming (FP)

I wanted to practice functional programming (fp) without using any library but using vanilla JS only. So I took a problem from Advent of Code (the 2nd part of Day 5): https://adventofcode.com/2017/...
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1answer
87 views

Advent of Code 2017 Day 5 (part 1) in Functional Programming (FP)

I wanted to practice functional programming (FP) without using any library but using vanilla JS only. So I took a problem from Advent of Code (the 1st part of Day 5): An urgent interrupt arrives ...
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1answer
78 views

Advent Of Code 2017 Day 4 (part 2) in Functional Programming (FP)

I wanted to practice functional programming (FP) without using any library but using vanilla JavaScript only. So I took a problem from Advent of Code (the 2nd part of Day 4) You can only access the ...
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1answer
73 views

Advent Of Code 2017 Day 4 (part 1) in Functional Programming (FP)

I wanted to practice functional programming (fp) without using any library but using vanilla JS only. So I took a problem from Advent of Code (the 1st part of Day 4): A new system policy has been ...
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1answer
39 views

Assign value based on 100s of switch statement

In the following code I have potentially hundreds of possible cases. (This is just a small subset.) Is there some way to more effectively set state.dimensionQty ...
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0answers
36 views

Elixir SQL Query Returning Structs or Counts

I have a few raw queries which are similar to each other in that it is mostly duplicate code with the difference being that one returns structs and the other returns counts of how many there are. How ...
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Advent of Code 2017 Day 3 (part 1) in Functional Programming (FP)

I wanted to practice functional programming (FP) without using any library but using vanilla JS only. So I took a problem from Advent of Code. https://adventofcode.com/2017/day/3 You come across ...
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1answer
87 views

Advent of Code 2017 Day 2 (1) in Functional programming (FP)

I wanted to practice functional programming (FP) without using any library but using vanilla JS only. So I took a problem from Advent of Code - i.e. Day 2: Corruption Checksum (below is the 1st part ...
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1answer
97 views

Advent of code 2017 Day 2 (2) in Functional Programming (FP)

I wanted to practice functional programming (fp) without using any library but using vanilla JS only. So I took a problem from Advent of Code (the 2nd part of Day 2): https://adventofcode.com/2017/...
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2answers
59 views

Advent of code 2017 Day 1 (1) in Functional Programming

I wanted to practice functional programming (fp) without using any library but using vanilla JS only. So I took a problem from Advent of Code: https://adventofcode.com/2017/day/1 The captcha ...
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2answers
283 views

Project Euler 7: 10001 Prime in Functional Programming (FP)

I wanted to practice functional programming (fp) without using any library but using vanilla JS only. So I took a problem from Project Euler: By listing the first six prime numbers: 2, 3, 5, 7, 11, ...
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1answer
190 views

Project Euler 8: Largest product in a series in Functional Programming (FP)

I wanted to practice functional programming (fp) without using any library but using vanilla JS only. So I took a problem from Project Euler: The four adjacent digits in the 1000-digit number that ...
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137 views

F# Operation Framework (Railway-Oriented Programming + Task/Async/Lazy)

I recently published the initial version of what is effectively my first open-source software package, a Railway-Oriented Programming Framework for F# that encapsulates Tasks, Async Workflows, and ...
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3answers
305 views

Project Euler 6: Sum square difference in Functional Programming (FP)

I wanted to practice functional programming (fp) without using any library but using vanilla JS only. So I took a problem from Project Euler: The sum of the squares of the first ten natural numbers ...
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2answers
93 views

Project Euler 5: Smallest multiple in Functional Programming (fp)

I wanted to practice functional programming (fp) without using any library but using vanilla JS only. So I took the a problem from project euler: ...
2
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1answer
157 views

Project Euler 4: Largest palindrome product in Functional Programming

I wanted to practice functional programming (fp) without using any library but using vanilla JS only. So I took the 4th problem from project euler: A palindromic number reads the same both ways. ...
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0answers
279 views

nom Parser in Rust

I'm attempting to make a parser using nom in Rust. Nom implements parser combinators, so more complex parsers are built from simpler parsers. Because of this, I've started with a simple ID token ...
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2answers
666 views

Sum of Even Fibonacci numbers in functional programming

I want to solve this problem in functional programming (fp) way only. Each new term in the Fibonacci sequence is generated by adding the previous two terms. By starting with 1 and 2, the first 10 ...
3
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1answer
73 views

JavaScript moneyFormat() function

Using JSX syntax I wrote a function that takes either a float or an integer as a parameter and returns a formatted string. I'd like any feedback for refactoring the code. ...
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3answers
1k views

Sum of multiples of 3 or 5 using functional programming

I wanted to practice functional programming (fp) without using any library. So I took the 1st problem from project euler: If we list all the natural numbers below 10 that are multiples of 3 or 5, ...