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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Flatten an array

I have got this interview question which has asked me to write a production level code which flattens the arbitrary nested array of arrays. Code ...
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Identifying Types of Triangle in Scala

Below is my solution to this exercise. Write a program that can tell you if a triangle is equilateral, isosceles, or scalene. The program should raise an error if the triangle cannot exist. ...
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Ordering data.frames elegantly by factor

I have a mock_Data: ...
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24 views

JavaScript image-Carousel with using IIFE

I have to implement an image-Carousel. Because I'll reuse the snippet within other projects which might contain all kinds of external libraries I used an immediately invoked function expression. ...
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Create an array with the highest values from each array

I am working my way through FreeCodeCamp's Javascript challenges and Return Largest Numbers in Arrays took me a minute. In this one the goal was to create an array with the highest values from each ...
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An interesting use of the reduce function to convert tab-delimited data into JSON

I am learning functional programming in JavaScript. This is some code from a video tutorial by funfunfunction. I am particularly concerned about the way the existence of the customer key is checked in ...
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50 views

Custom map on `Array`

I have the following problem: Given an Array, apply a certain method x to each Array ...
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63 views

Switch expression function

I made a bunch of functions and an enumeration, that together allow me to write something like a switch expression. It's not as powerful as Swift switch statements, since it's lacking pattern matching ...
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41 views

Add functionality to object then remove those functions on export

Outline I have a form that needs validation. The problem is that the software requires custom validation that depends on multiple parameters. I decided to pass the object into a function which will ...
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55 views

Create a generator that returns every permutation (unique arrangement) of positive integers up to n

I watched this video from The Unqualified Engineer on YouTube and tried out the challenge. The challenge (or interview question) is to build a generator that returns all the permutations of the ...
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34 views

`new Function` for json reference

I have JSON with references to other parts in that JSON file. ...
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62 views

childrenCount function in old and functional styles

I'm trying to transition myself from my old coding-style (if-else, for.. in) to functional programming. I've tried to update the ...
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56 views

Count the number of vowels and consonants

So I needed to write a function that takes a string and returns a javascript object with vowels and consonants properties that maps to the number of vowels and consonants in the string ...
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36 views

JavaScript-function for to convert a dash-separated string into camel case

I have to write a function which turns a string with the words separated by dashes ( - ) into a sentence using camel case notation. I've had the following idea for an implemenation using the reduce-...
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41 views

Concat strings from Object or Array

How would you merge these two functions into a single more generic function? ...
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29 views

Loading URLs via a case statement

I have the following code which loads in a URL based on the id of a user-clicked button. I'm looking to compress it down as much as possible, and make it more modular and reusable: ...
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40 views

Tool for composing functors

What do you think of this code? ...
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Python common file operations generalization

Functions with common and simple file operations have started to repeat in my code. Many like this one, but with subtle differences for example: ...
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50 views

Extendable JavaScript module that converts between camelCase, PascalCase, and underscore_case

The basic idea is that by defining the basic functions--recognize, dissect, and combine--...
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1answer
54 views

Stock performance app

I'm building an app that tells you a stock's percentage change in price between two dates by using Yahoo's API. Given a stock ticker and two dates, it currently outputs the percentage return to the ...
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53 views

Determine whether input-output pairs represent something that could be a proper math function

The input is read in line by line from stdin. Input Format The first line contains an integer, T, denoting the number of test cases. The subsequent lines describe T test cases, and the ...
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Read group of keywords from file, modify value, store new group to variable

I would like to use the following routine in my submission script for GAMESS calculations. I am not entirely sure if this is the optimum way to go. This function would need one of the messaging ...
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Checking if input file exists, assign output file destination, prevent overwriting any files

I would like to use the following routines in my submission script for GAMESS calculations. Before I do, I would like to get some input if I can improve it somehow. The three messaging routines (<...
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52 views

Gulp task to increment a major, minor, or patch level of the version number of the last build

Working codepen: http://codepen.io/leongaban/pen/oxwLzE?editors=1010 The function below takes in user entered text through the cli: V=patch gulp build It then ...
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Merging trees in scalaz

I just built a function to merge a set of List[A]s into a single scalaz.Tree[A]. Specifically, if I have the following three <...
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26 views

JavaScript function for logging the members of an object (with horizontal alignment)

When iterating over the members of an object for logging the keys / values one gets a "stair case" effect. Therefore I wrote myself this function which takes care for a left-alignment of the values. ...
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53 views

Clojure reverse multiple times

I have a piece of Clojure code that reverses a string recursively. It is working but too slow (because I got the problem from Codewars and I cannot validate it ...
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PE # 34 - “Digit Factorials” with no loops

I posted a similar question “Curious Numbers” (HackerRank PE 34) recently (but in a different language/platform altogether). I'm starting to learn JavaScript and decided to take the challenge again ...
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Find zeroes in a matrix

I am looking for the elements that are zeroes in a square matrix (of size n), as a list of pair. I don't really like the following code, some condition seems ...
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100 views

“Curious Numbers” (HackerRank PE 34)

I was inspired by a certain recent question to try my hand at this challenge: Project Euler #34: Digit factorials \$19!\$ is a curious number, as \$1!+9!=1+362880=362881\$ is divisible by \$...
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Document term matrix in Clojure

This is my very first foray into Clojure (I'm normally a Python-pushing data-type). I'm trying to create a simple term-document matrix as a vector of vectors, out of a vector of strings. For those ...
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117 views

A curry function

I am new to the functional style, and I wrote a curry function to practice this new style. This curry function takes a regular function and returns the curried version of it. Currying is a technique, ...
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121 views

Longest palindromes

I've been tasked to solve this exercise lately, and this is what I wrote: ...
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60 views

C++ idiom for selecting integers from a vector according to predetermined properties

I want a function Select that takes a vector<int> and a condition (such as being even, being divisible by three, being ...
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57 views

All possible ways of merging two lists while keeping their order

I am writing a function gives all possible ways of merging two ordered lists such that in the merged list, the elements are still ordered according to the elements in their respective starting list. ...
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81 views

Recursive function application

I use a lot T4 templates and want to avoid extra code writing when it could be generated. Currently I have following class: ...
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Reformatting a structured string like “a-b-c|A-B-C” into “a-A|b-B|c-C”

The code below was inspired by this post in Code Review. Here is how it was first intended by its author: I have the following code that converts a string that looks like : aaa-bbb|ccc-ddd|eee-...
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Extracting data for a tag cloud using Lazy.js

I've just started using Lazy.js, which is my first exposure to a "functional style" javascript library. I'm still utterly lost as to which of the hundred different functional javascript libraries to ...
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Compiler for a minimal LISP dialect to run on the Java Virtual Machine

As the title states, this is a compiler written in C with a ruby build script that translates a minimal LISP dialect and spits out an executable jar file. I designed this LISP dialect and named it ...
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Quick-sort a linked list?

I have a little project where i am implementing an immutable linked-list (not only...) based on a pair-structure like the LISP cons-cell. The linked list works well and is basically wrapping two ...
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Refactored version of Okasaki's skew-binomial heaps in Standard ML

In his book, Purely Functional Data Structures, Chris Okasaki provides an implementation of skew-binomial heaps (p. 137). Unfortunately, the book isn't (legally) freely available anywhere, but his ...
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64 views

Functional Scrabble Word Score

Homework: Write a function to score a scrabble word. values is a global dict formatted as values = {'a': 1, 'b': 3,...} The ...
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123 views

Object-oriented web scraping with Python

I usually write function-only Python programs, but have decided on an OOP approach (my first thereof) for my current program, a web-scraper. Here is the working code I wrote which I am looking to have ...
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ES6 block-scope variable usage

I am experimenting with ES6 using BabelJS in a codepen project you can find here. I am confused as to why my code breaks when I decide to use let instead of ...
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68 views

Functional translation of dice simulation

I have tried my hands at "functionalising" a toy problem I had: find the expected number of throws of a six sided die until all sides have been seen (the answer is 14.7) My starting point is my ...
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Option<T> functional type implementation and scenarios

Have you ever being implementing Option<T> functional type? It is discussed here. Basically, it is about using ...
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112 views

Functional Javascript Practice with AJAX

I am currently doing projects in freecodecamp.com to brush up on my javascript skills and just finished a weather report widget. It does the following: Gets api ...
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PBKDF2 and HMAC implementation in Scala

First of all: I know that rolling your own cryptographic functions is bad. The SHA256 implementation i use is from Bouncycastle, but i think both HMAC and PBKDF2 are not vulnerable to timing attacks ...
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Implementing an inner product using pyspark

I'm trying to implement a dot product using pyspark in order to learn pyspark's syntax. I've currently implemented the dot product like so: ...