Questions tagged [f#]

F# is a succinct, expressive, and efficient functional and object-oriented language for .NET

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1answer
5 views

How to apply multiple filters in one statement

While trying to grasp the potentials of the collection features in F#, I encountered this one: ...
4
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1answer
109 views

Handling bill cancellation

I'm trying to refactor the working code below which intends to handle bill cancellation, but doesn't seem "linear" enough. ...
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54 views

How to flatten the nested try-catch block in F#?

How to flatten the nested try-catch block in F# for the following code? I am using EF Core with F#. The nested is required because I need to Rollback the transaction if there are errors in saving or ...
7
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1answer
121 views

Refactoring of two command handler implementations with F# in the context of event sourcing

I've written some F# code to handle commands in the context of event sourcing which works along the lines below: Read Events from a specific event store stream Build the current state in the given ...
5
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1answer
117 views

Converting a float to a fraction as a string

I was inspired by this video by Matt Parker to use the Farey Sequence to convert a float into a string representation of a fraction, how did I do? How well did I follow F# workflow and patterns (I'm ...
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1answer
77 views

Simple Password Generator Feedback

This is my first major project in F#, looking for any critique on how I can make it more standard or more concise. Some things I feel like I could have done better are the command flag parsing and the ...
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1answer
87 views

First-time F#: A simple Rock Paper Scissors

This is my first F# program. It's a simple Rock-Paper-Scissors implementation. I am looking for feedback of all sorts, e.g. the choice of types (e.g. List vs Array), whether there are parts that could ...
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1answer
92 views

CodeWars Deodorant Evaporator

How can I make the solution to this https://www.codewars.com/kata/5506b230a11c0aeab3000c1f/train/fsharp more "functional"? ...
4
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1answer
69 views

Return early with Error from Sequence mapping

I have put together this f# code in an attempt to solve the following problem Given a mapping operation that may not be able to return a value Cease mapping over the remaining items of a sequence if ...
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3answers
135 views

Idiomatic F# for iterating a seq and mapping whenever changes occur on a given selection

I've written a function that takes a sequence and check for every item in that sequence whether the current value a selection (obtained with a selection function) is different (or on the first ...
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1answer
37 views

F# Array with tuples or Map

I have a sample code and some question. Simple type property ...
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126 views

N-Queens Puzzle

The N-Queens puzzle can be solved in many ways. One is by a depth-first-search backtracking algorithm. Below is my generalized version using mutual recursion: ...
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2answers
90 views

Advent of Code 2019 day 2 in F#

I sped through the 5hr F# pluralsight course this week-end and thought I'd sement my learning by going through as many Advent of Code puzzles I could with this new learning. However, already on day 2 ...
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90 views

“Rock, Paper, Scissors +” in F#

During a discussion in a development chat, a user suggested to another (in the context of C# originally), UserA: Challenge: Create an implementation of RPS, and then show how it can be extended to ...
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2answers
95 views

Solving the game Set in F#

I was playing the game Set online, and thought it would be a good exercise to write an F# script to find all of the sets for me. The rules of set are as follows: A SET is 3 cards for which each ...
3
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1answer
206 views

F# Binary Tree and Tree Traversal

So for an side exercise on exercism I implemented a BinarySearchTree. I was confident in implementing the creation of the binary tree. But I'm very unsure about the traversal of the tree. So I came ...
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0answers
51 views

Functional Dependency Injection Abstraction

The F# web-development framework Giraffe supports a functional style of Dependency Injection using a form of the Reader monad, as explained in this GitBook. I would like to use this pattern more ...
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1answer
77 views

Assigning jobs in a functional style

I'm new to F# and functional programming in general (coming from an object oriented background). I just wanted to get some criticism on an algorithm for assigning jobs to crew members. I want to be as ...
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0answers
78 views

Flashcard Website

In my endeavor to learn Angular, I've created a flashcard site with an F#/Mongo backend. As I'm new to Angular, I'm going to post everything; any and all feedback is welcome. First, some pictures of ...
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1answer
127 views

Simple queue on F#

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1answer
70 views

F# method to insert, update, or delete events in a dictionary

I have the following code: ...
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1answer
85 views

Asp.net middleware [closed]

This code is asp.net core middleware written in f# and called from c# for a blazor server-side app. How can this be made more efficient if any in regards to the async code. F#: ...
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0answers
80 views

Sanitize input for a “robot on a grid” kata

I have the following piece of code which is FSI tested and works. However, I want to trim it as much as possible (not only the comments, which are there for my own future reference) and make it as ...
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2answers
87 views

Query a product from a list of brands

I am quite new to F# and just wrote my first program. It checks if the query exists in the brand list and returns the matching brand. Query is the string you are searching for in the brand list. So ...
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0answers
39 views

Photo rename by Exif date and group into folders with a threshold

I wrote this tiny F# project yesterday, but I am a bit rusty and I would like to know if there is anything I can refactor and make more elegant. ...
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0answers
127 views

F# XML Generation in .NET Core: XmlSerializer or XmlProvider

I am working on SEPA XML generator in F#. I developed two solutions that are roughly equivalent, one relies on the XmlSerializer while the other relies on ...
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1answer
114 views

Idiomatic way to write proper F# (x)unit + fsunit tests?

I am writing some unit tests using XUnit in F# and I am wondering what is the most idiomatic way in the F# sense to write them. Let's start a simple case: ...
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2answers
259 views

Asynchronous IBAN API with validation

I am working on an iban api which is about saving the iban of some members after (iban validation) in a database. The code is split between Domain (entities, behaviour for iban validation), Database ...
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0answers
53 views

F#, Timer and propperly removed ElapsedEventHandler

I have a simple method that receives messages from bus, builds response and send it back, and it looks like: ...
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1answer
62 views

F# Simple message reader using TCP

I have a review request about this part of the code: ...
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1answer
84 views

Binary Trie in F#

I have this little exercise writing a binary trie in F#. In C# it can be done in few lines, but here it became more complicated than I had expected (especially the ...
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1answer
189 views

Convert to and from variable length quantities

As part of small MIDI library i've implemented the conversion of a VLQ (variable length quantity) for byte[] -> bigint and ...
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0answers
135 views

Async in Railway Oriented Programming in F#

In F# the Railway Oriented Programming pattern can be implemented synchronously using the Result<'t,'terr> type as result value for functions, so they can be ...
6
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1answer
67 views

F# pattern matching to determine the state of a bank account based on past events

I am writing an event sourced system in which I need to have the state based on the events that already occurred for a given bank account. The events are defined such as: ...
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2answers
168 views

Tcp server messenger awaiter in f#

Hi I have a simple tcp server, and that server receives messages with specific length so basically i need to wait for TcpClient to fill buffer with that amount of data, and it works. But I am not ...
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0answers
106 views

A simple functional F# wrapper for EasyNetQ

This is my first attempt at creating a small module to wrap the .NET library EasyNetQ in F# to make it more functional. I am pretty new to F# and I would like to get feedbacks on everything: types, ...
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2answers
153 views

F# wrapper to generate SHA256 signature for a file

I've created the following module to allow me to generate a SHA256 signature for a file. (In real life this is used to verify an image file hasn't been amended). The cut down code looks like this: <...
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2answers
185 views

Roman Numbers - The Functional Way

Yet another exercise in converting values between the decimal and roman number systems. I have tried the functional way. Any comments are welcome - but I'm especially interested in answers focusing ...
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1answer
44 views

Concise way of “updating” element in nested collections

Imagine simple game: ...
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1answer
76 views

F# parse data and calculate sum

I decided to play with F# and found simple task on Codewars. The task is sounds like "Calculate Sum/Mean/Avarage for selected City". I decided to calculate only Sum. My solution is horrific. I would ...
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1answer
75 views

Project Euler Problem #102 in F#: counting triangles that contain the origin

I've recently decided to get into functional programming with F#, and decided to learn the language through Project Euler. The following is my implementation of problem 102: Problem: Three ...
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1answer
239 views

Convert bitcoin value based on exchange rate from JSON API

I’m learning F# and trying to find a more ‘functional’ way to code a simple program that retrieves the price of BTC and calculates the EUR value of an amount of Bitcoin. ...
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0answers
43 views

Creating idiomatic and efficient method to stream large JSON file

The purpose of the code is to efficiently stream JSON items from a large file. I am wondering if this is efficient and decently idiomatic. Not sure how I could eliminate the while loop either. ...
4
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1answer
58 views

Analyzing spoke overlaps during rotation: Round 2

Round 1: Analyzing spoke overlaps during rotation I previously posted this question, but I've changed a lot of the code since then. There was a mention of the previous being a bit mixed up, and things ...
6
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1answer
59 views

Analyzing spoke overlaps during rotation

For a personal project that I've recently started I have to analyze the rotation of two shapes with sets of spokes, where the spokes are evenly-spaced, and split into a given number. That is, if I ...
6
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1answer
85 views

Verifying that three cards make a “Set”

The game of Set involves cards with four properties: number, symbol, shading, and colour. Three cards make a "Set" if the property is either all the same or all different across the three cards, for ...
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0answers
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Blockchain implementation in F#: Wallet

Introduction This is Part 3 of my F# blockchain implementation. Previous parts: Block and Blockchain Transactions Code In this part I am implementing a wallet functionality. The code is based on a ...
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2answers
585 views

Advent of Code 2018 day 1 part 2: find the first aggregated number that occures twice

I am using the coding puzzels of https://adventofcode.com for improving my F# skills. Problem: Day 1 Part 2: Starting with frequency 0, a list of numbers should be added successive generating new ...
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2answers
275 views

Conway's Game of Life F#

I am a C# developer learning F#. Would appreciate any suggestions on how this code can be improved. Main points I am interested in: Functional style of the code, absense of imperative style(C#) ...
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0answers
76 views

Blockchain implementation in F#: Transactions

Introduction This is Part 2 of my F# blockchain implementation. Previous parts: Block and Blockchain Code This time I am tackling transactions. The code is based on a JavaScript blockchain ...

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