Questions tagged [f#]
F# is a succinct, expressive, and efficient functional and object-oriented language for .NET
350 questions
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F# - Recursively find the first available item in a range definition
I have the following EF Core table:
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2
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921
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F# railway style vs lazy seq
The following code is an example of railway-oriented programming that allows a password string to be validated:
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3
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2
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139
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Convert environment variables (from linux env cmd) to json (supporting nestedness) in plain F#
I stumbled across something a long while ago, fetching the environments variables from say env under linux (say on a pod via argos), anyway, point is I could fetch ...
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161
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Returning different elements between a Hashtable and list<string> in F#
I have two collections:
A list of strings
A hashtable
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- 123
3
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278
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Command line wordle
I am seeking a review of my command line wordle game.
Having only recently started exploring functional programming, I expect that there will be no shortage of areas to improve. This is my first ...
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1
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206
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Sieve of Eratosthenes in F#
after looking at the pseudocode for the Sieve of Eratosthenes on wikipedia I tried implementing a similar version using F#. The code runs just fine, that is, it returns all prime numbers up until a ...
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138
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Download and parse XML data from a URL every minute with F#
The purpose
This code is intended to achieve the following goals:-
Create a hard coded list of lifts, this is pretty static and I add some extra info so I'm ok with this being in the code but I may ...
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1
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106
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Cardinal to ordinal numbers in F# code reuse
I've been experimenting with the F# Bolero environment to learn F# a bit and I was trying to get the hang of pattern matching by generating ordinal numbers (1st, 2nd, 3rd, ...) from cardinal numbers (...
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F# simple monoalphabetic cipher code implementation
I am a new F# programmer, and a student in a security class. As part of my notes, I wrote a small implementation of a monoalphabetic cipher as follows:
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101
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Retrying failed calls to a crypto exchange
This code represents logic used to retry failed calls to a crypto exchange:
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3
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196
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How to refactor the boolean logic of this F# function?
I have a list of path I want to filter out. I want to keep only paths matching a specific pattern and remove all paths matching another specific pattern.
To achieve this I pattern matched on each ...
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What would be this best way to show that my function can accept some specific numbers as input? [closed]
I am writing a credit card generator. I have method GenerateVisa() who will return either a 13 or 16 numbers string.
This is the default value but GenerateVisa can ...
- 561
3
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330
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Print each word of a sentence in a new line
this is my first F# program, very simple concept but took me a few minutes to get it. I'm new to functional programming so I'd appreciate if you could have a look ...
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99
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Downloading multiple log files
This code succeeds in downloading log text files from multiple URLs. Can this be made more efficient?
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2
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925
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What would be the idiomatic F# way to write optional parameters?
In the context of a library to generate random credit card, it would be nice to let the user the possibility to set some optional options on some cards. Lets take Visa. Two lengths are available: 13 ...
- 561
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1
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143
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Maintaining state while walking a tree structure
The following code creates a simple tree structure and then walks through the tree looking for node with the value 9 that appears after we have seen a node with the value 1 and a node with the value 4 ...
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166
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How to apply multiple filters in one statement
While trying to grasp the potentials of the collection features in F#, I encountered this one:
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1
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184
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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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7
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1
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239
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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 ...
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192
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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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2
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149
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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 ...
6
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1
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150
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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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4
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1
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271
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CodeWars Deodorant Evaporator
How can I make the solution to this https://www.codewars.com/kata/5506b230a11c0aeab3000c1f/train/fsharp more "functional"?
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4
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1
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219
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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 ...
- 193
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3
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406
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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 ...
- 1,145
2
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268
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F# Array with tuples or Map
I have a sample code and some question.
Simple type property
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0
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196
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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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user73941
2
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2
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145
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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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197
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"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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145
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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 ...
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861
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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 ...
3
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0
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147
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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 ...
- 551
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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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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 ...
user34073
3
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1
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435
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4
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1
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161
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0
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1
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157
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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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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 ...
user52901
3
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2
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149
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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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450
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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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398
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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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328
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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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1
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F# Simple message reader using TCP
I have a review request about this part of the code:
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4
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1
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168
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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 ...
user73941
4
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1
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272
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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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294
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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 ...
user73941
6
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1
answer
102
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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:
...
- 1,145
4
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2
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291
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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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209
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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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659
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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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