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Questions tagged [clojure]

Clojure is a Lisp dialect for the Java Virtual Machine. Its main features include a software transactional memory system for coherent updates to data structures, transparent access to Java libraries, a dynamic REPL development environment, runtime polymorphism, and built-in concurrent programming constructs.

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Table of employee with end of mission visual clue

to learn Reagent, re-frame and spec I made a little personal project. Description: Given a ...
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1answer
43 views

Langton's ant in Clojurescript

The weekly coding challenge in Eric Normand's newsletter this week involves implementing Langton's ant. I wanted something on my screen so I put together a simple re-frame app. The core functions ...
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77 views

Extract indices of visible nodes in a tree where only some nodes are expanded

A program that I work on constantly updates and modifies program state containing an arbitrarily deep and wide tree. The data looks something like this. ...
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1answer
57 views

n-puzzle in Clojurescript

I'm in the process of creating a n-puzzle solver in Clojurescript. I have the basic model up and running and can move tiles on the screen. I plan to implement A* or such an algorithm to solve a given ...
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1answer
32 views

Picking a random point along the edge of an area

I'm writing a Diffusion-limited aggregation simulation, and need to pick a random point along the edge of an area defined by a dimension pair of [width, height]. ...
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2answers
95 views

Parsing infix expressions in Clojure

I'm trying to teach myself Clojure by reading the Brave Clojure book online, and at the end of Chapter 7 there is an exercise to parse a mathematical expression written as a list in infix notation to ...
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1answer
26 views

Using deftype to create a wrapper class for byte arrays

I want to create a wrapper class for byte arrays so that I can use them as keys in fastutil's Object2LongAVLTreeMap. I have ...
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104 views

Forest Fire Cellular Automata

I stumbled on the idea of a Forest Fire simulating cellular automata, and decided to try making a version using a full Seesaw UI (a Clojure wrapper over Java's Swing). A short sample of it running is ...
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53 views

What does the Bob say? (clojure version)

I'm doing the exercices from clojureacademy. Here are the instructions for this one. Bob is a lackadaisical teenager. In conversation, his responses are very limited. Returns "Whatever." if ...
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56 views

RSS feed viewer in Clojure

This semester a classmate and I visited a course on functional programming in our university. For grading, we've to submit a small project which should be written in Clojure and make use of functional ...
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2answers
117 views

Project Euler problem 86 taking a long time

I'm trying to solve problem 86 in Project Euler. After some tinkering, I managed to unroll the DP solution into a loop. But still the solution takes >150s to complete. What can I do to improve the ...
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39 views

Naïve Prime Factorization in Clojure Pt. 2

After my last review request, I decided to try and make a "tree" visualization, and thought that I could benefit from making find-prime-factors lazily produce prime ...
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36 views

Powerset of collection in Clojure

Similar to this question, here's another implementation. Assume the input is already a set. ...
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41 views

Naïve Prime Factorization in Clojure

I saw a question about prime factorization on Stack Overflow and realized I had never attempted it before. This was what I ended up with after some playing around and tweaking. I'd like improvements ...
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70 views

Project Euler #10 (sum of primes less than two million) in Clojure

I'm new to Clojure and using some Project Euler problems to familiarize myself with the language's capabilities. Problem #10 asks to find the sum of all primes less than two million. I wanted to ...
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1answer
99 views

Program finds the first almost matching string in a list - Advent Of Code 2018 Day 2 Part 2

Advent of Code 2018, day 2, part 2: The [two IDs you are looking for] differ by exactly one character at the same position in both strings. For example, given the following IDs: ...
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1answer
60 views

Five functions to get the digits of a number

I'm writing a simple function: given a number, it will return a sequence or a collection of the digits in the number (in the correct order). i.e ...
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2answers
93 views

Project Euler #49: Find 12-digit number concatenating a three terms sequence

First of all, project Euler has been a great help for me to learn Clojure. I tried for months trying to get web projects going but ended up frustrated with and struggling with tooling and libraries ...
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99 views

Project Euler 23 implementation

This code to solve Problem 23 in Project Euler gives the correct answer. But, running the last expression takes around 40 seconds. I welcome advice on how to improve performance here. ...
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44 views

Number Stringifier in Clojure

As an exercise, I decided to write a program that spells out numbers. For example: (stringify-int 12345) => "twelve thousand three hundred forty-five" It ...
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2answers
72 views

Classic “100 doors” simulation in Clojure

I read this question about the "100 Doors" puzzle, and thought that it would make for a good quick exercise. I ended up with two implementations. The first is more straightforward and uses a vector ...
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Clojure macro to gather functions in a namespace into a map

I'm learning Clojure via a pet project. The project would consist of several workers that would be called from other functions. Each worker is defined in their own namespace as a set of functions (...
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2answers
37 views

Recamán Sequence (A005132)

I'm going to screw around with visualizing Recamán's Sequence, but want to have a good sequence generator to generate the sequence before I start. I want to use a lazy generator for my actual ...
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1answer
117 views

A* in Clojure - trickier than I expected

While working through some coding puzzles to brush up on Clojure, I encountered the need to use A* on some search problems. I tried to implement it from first principles/memory and that didn't go ...
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150 views

Avoid incoming meteors

I'm visiting a functional programming course at my university which has a small project for examination. The language we are using is clojure and the contents of the lecture have mostly been about it'...
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Cleanly preventing flashing an element from corrupting future flashes

For a Seesaw (Swing) app I'm writing, I need to be able to flash a component for a certain duration. Here's the basic function I came up with that accomplishes this: ...
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1answer
49 views

All of Clojure's Expression Threading Macros

I was bored and in a mood to write some macros, so I decided as an exercise to try and remake each of the standard threading macros: ->, ...
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1answer
50 views

Mutative Heap's algorithm (permutations generator) in Clojure

For a side project I'm working on, I need to be able to generate permutations. Instead of relying on an existing library like math.combinatorics, I decided to write ...
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59 views

An ISeq implementing Priority Queue

This is a follow up to my last review request. I made three major changes: I had it fully implement ISeq and IPersistentStack, ...
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52 views

A Priority Queue implemented using a Linked List

I'm going to write a Huffman Coding implementation, and decided to write from scratch a priority queue to help out. I've never written a priority queue before, in any language, so this was interesting....
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1answer
106 views

Kids bank account in Clojure

I'm learning clojure. A while back I made a python bank account for my kids, teaching them to save. Have a look here. The Python one was a class and it created a table that had a little interest ...
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1answer
86 views

Implementing parser combinators in a functional manner

I am just starting on my journey of learning clojure (I have just read to the end of chapter 3 in clojure for the brave and true). So for practice, I wrote some parser combinator functions. I am quite ...
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1answer
38 views

Pascal's Triangle - Remove hack

I had a thought last night on how I could easily write a Pascal's Triangle generator basically just using partition and map. I ...
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1answer
79 views

Sorting texts by similarity in Clojure

This is my first attempt with a lisp language. I'd like your review to address the following points, already listed in order of relevance: Is my code making good use of standard library? Is my code ...
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1answer
43 views

Finding the comic ID of the last XKCD comic published

I decided to sidetrack and create a XKCD viewer. For certain functionality, I needed to be able to find the ID of the last comic published. This was my attempt. I'm using Enlive here to parse the page ...
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1answer
157 views

Functional Sieve of Eratosthenes in Clojure

For some reason, this is the first time I've ever written an implementation of the Sieve of Eratosthenes. I basically just stared at the Wikipedia walkthrough of the algorithm until it made sense, ...
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1answer
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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Generate a random, nested map

To answer a question on Stack Overflow, I needed to generate a large, nested map that I could postwalk over to do some testing. After a couple stabs, this is what ...
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64 views

Macro that allows for Linear Problem notation to create Genetic Algorithm fitness functions

As a side toy project for my Genetic Algorithm, I decided to try to create a macro that lets you use maximize: ... subject to: ... linear problem notation to ...
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1answer
90 views

A running gene crossover function for a Genetic Algorithm

I'm writing a Genetic Algorithm, and need to write a function that crosses two gene sequences. Basically, I want it to work like this: ...
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1answer
86 views

Clojure “Game of Life”

I'm a Clojure beginner and I implemented Game of life to learn how I should code things in Clojure. ...
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1answer
302 views

Linked list implementation in Clojure

Background Linked lists are a well-known data structure, so I won't waste too much detail on them. Suffice to say that a linked list consists of "cells". Each cell contains some kind of value and a ...
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1answer
100 views

Rock-Paper-Scissors game in Clojure

I followed braveclojure book and built this little command line Rock, Paper, Scissors game. The game works fine, but I was wondering if there is a better / more ...
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75 views

Performance concerns when solving sliding-tile-puzzle via A* algorithm

I have implemented n-puzzle solving in Clojure using A-star algorithm. The following code, when used like this: (solve [0 1 2 3 4 0 6 7 5 8] 3) would return ...
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2answers
29 views

Predicate testing for equality that returns the common element

I'm going to try brute-forcing the solving of a Magic Square. To simplify the code later on, I wanted a function similar to =, but one that returns the common ...
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1answer
126 views

Bloom-filter implementation in Clojure

Background Bloom-filter is a data structure to which we can insert elements, and check if it already contains a given element. The peculiarity is, that if a ...
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2answers
69 views

Find the middle of the string

The follow code should correctly run the test cases at the bottom. It works correctly. I just don't feel like this is clearest way I could write it. A lot of the complexity comes from having to ...
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Sierpinski Carpet using Seesaw

I decided to write a Sierpinski Carpet generator. This has been something I wanted to try since watching the Coding Train this summer. A screenshot of it in action with some experimental coloring: ...
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1answer
45 views

Find combinations of items in a nested collection

It's a very typical problem that I come across here and there. Imagine that you have a collection of items of any type, and sometimes items are collections themselves; you then need to "expand" them ...
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45 views

SQL-like syntax to sort and filter a collection

I was helping someone on SO with an assignment to create a macro that accepts an SQL-like syntax, and optionally sorts and filters a collection. I realized that while their instructor is insisting on ...