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

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55 views

Add spaces before uppercase letters

I'm trying to convert some very simple C# string utility functions to F# as a learning exercise. Ignore the fact that the C# version is implemented as an extension method for the moment. The ...
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58 views

Encoding the problem domain of products and prices into the typesystem in F#

I'm trying to design a model for purchasing amounts of products in F#, following the ideas for designing for correctness (source). The idea is to use the type system to capture the different legal ...
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45 views

Project Euler 3 in F#

I'm looking for some general feedback on my solution to Project Euler challenge 3 The prime factors of 13195 are 5, 7, 13 and 29. What is the largest prime factor of the number 600851475143 ? ...
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60 views

Project Euler #2 in F#

Project Euler Problem 2 asks for the sum of all even Fibonacci numbers below 4 million. My first attempt at this problem using functional programming with F#. I would've liked to use some kind of ...
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2answers
434 views

Project Euler Problem 1 - Functional approach?

I'm trying to learn F# right now coming from C# and I'm finding it a great difficulty to "reconfigure" my mind to the functional programming mindset. So I'm going to attempt a few Project Euler ...
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155 views

Is this Bridges code F# idiomatic?

Introduction I'm primarily a C# programmer, just starting out with learning F#. I found myself with a problem which felt like it was appropriate for a functional language, and now that I have the ...
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1answer
102 views

Simple actor system in F#

Any thoughts on my actor model here? Obviously it doesn't have implementation for concurrency as it stands- being completely synchronous, but it should be easy to make the send/become/create be sent ...
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2answers
124 views

Longest Common Subsequence and Longest Subsequence Palindrome

The following code computes: The longest common subsequence between two strings, where a subsequence of a sequence does not have to consist of contiguous elements of the sequence. The longest ...
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1answer
105 views

The Functional FizzBuzz Kata

I run a coding dojo at work. For one session I'm to showing that you can use a kata to get into a new language. I'm using the FizzBuzz Kata to to show F# (and JavaScript) because it is short. The ...
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108 views

Excel calculation engine

We have currently rewritten an Excel calculation engine in F# and are looking to refactor the code to make it a lot more idiomatic and standardised. One of the big problems with the code is that we ...
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2answers
100 views

Idiomatic and Conventional F#

As of late I have been learning F#. Today I accumulated what I have learned so far to develop my first program - a script that counts the number of lines of code in a given Visual Studio project. ...
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1answer
25 views

Searching for files across multiple code projects

I was tasked with conducting a large number of text searches in the code files of multiple projects. Initially, I just used the Find in Files feature of Visual Studio in a couple of the running ...
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98 views

Split string into parts of varying lengths

I need to split a string into parts of varying predefined lengths, given as a sequence of integers. After a first imperative attempt using a sequence expression and a reference cell, I have now come ...
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'Countdown' Numbers round - combine numbers arithmetically to reach a target

Countdown is a British gameshow where contestants compete in word and number challenges. During the numbers round, six numbers are chosen semi-randomly and the task is to combine them using addition, ...
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66 views

Detecting connected acyclic through Tarjan strongly connected components variant

I want to verify that a given directed graph is connected and acyclic (DAG). I have implemented a modification of the Tarjan's strongly connected components algorithm in imperative style (as the ...
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2answers
194 views

Detecting properly nested parenthesis using functional programming

So I have this code that is my attempt at a coding test from Codility. While my code produces correct results according to the requirements, (which unfortunately are copyrighted so I don't think I can ...
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1answer
107 views

Join() equivalent function for F# sequences

I am porting C# code to F# that makes use of LINQ's Join() extension method. Just as I use that in method call chains, I would of course like to have an F# function ...
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2answers
81 views

Tail-recursive query string builder in F#

I have a situation where I'm generating a URL based on a set of query string parameters for use in an API. I know ahead of time that the values passed to this function are URL-safe and the tuples are ...
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1answer
208 views

Good usage of MailboxProcessor/Agent in class rather than mutable field?

I've written a simple Simple Service Discovery Protocol (SSDP) module. This module contains a class, Session that you create and then use to issue commands and ...
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65 views

Refactoring while-do array comparison function into tail recursion with F#

As part 2 of my other question concerning this long running project I've been inquiring about on CR, I reimplemented my generic function for determining if an array of arrays is a sub-array or ...
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1answer
73 views

Refactoring while-do into tail recursion with F#

I have a while-do loop nested inside a while-do loop in my program, due to it needing to iterate in two dimensions through an array of arrays, and originally my loop looked like this: ...
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3answers
215 views

Functional Programming style in F#

I'm normally a C# developer, but I've started to learn F# and I want to make sure I'm writing code in a functional way that suits the language. I've quickly pieced this together with my knowledge from ...
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2answers
81 views

Discount curve from instant rate

This my first foray in F#, and I cannot think (yet) functional. I have implemented an interface for a discount curve and the implementation for a piecewise constant instant rate implementation. I ...
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1answer
99 views

Locating a bitmap inside another (larger) bitmap with F#

This is my firstish (heavily rewritten) go at the completed project that I've been working on with CodeReview assistance, so further advice is appreciated! See here, here and here for the past history ...
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64 views

Replacing an F# loop over a mutable variable by an immutable approach

Consider: let mutable m' = m while m' % i = 0L do m' <- m' / i I've refactored it into: ...
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1answer
66 views

Transform Bitmap object into jagged array of RGB tuple values

I've been working on this module with the assistance of codereview, and based on the responses and my own research, this is my project so far. The goal behind the code is that it starts with a .NET ...
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1answer
117 views

Ugly Numbers: A Rags-to-Riches Story

I stumbled upon an unaswered question, which looked like a good fit for a functional programming language. Here is the problem statement from codeeval: UGLY NUMBERS CHALLENGE DESCRIPTION: ...
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139 views

Generating the pretty bit at the end of a URL

I'm having a dip into F# and am attempting not to write it like it's C#. One area that bothers me is using members of System.String. These often need to be chained ...
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1answer
81 views

Transforming a byte array into an array of byte arrays with F#

This code is intended to be used with an image manipulation library that I'm working on, and the goal is to take the raw byte[] data from an image, and transform it into a 2D array where each position ...
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1answer
51 views

Load bitmap object data into array of byte values

I'm building this as part of a larger class to rapidly search for smaller images inside larger images. This is my first serious F# project so comments especially concerning style and organization are ...
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1answer
98 views

A functional binary heap implementation

I've implemented a binary heap in F#. It's pure and uses zippers for tree modification. To test it out I have implemented heap sort using it but it takes 10 seconds to sort a list of 100 000. Regular ...
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97 views

Fibonacci number function: convert to tail-recursion?

I've been implementing a function for calculating the nth Fibonacci number in F#. So far the best implementation I could come up with is this: ...
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1answer
131 views

Parsing sections from a log file using F#

After reading a lot about F#, I am today cutting my very first real life F# code and I'd appreciate any feedback on my approach. I'm writing a simple utility to analyse a log file. The code below ...
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2answers
92 views

Defining a zip code string

I'm following this ...
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0answers
45 views

Retrieve records from the database based on a possible id

This code will retrieve all records from the database if the id is null or return records by the available id. Is there a way to combine the query instead of having two separate queries? ...
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41 views

Check the database for an order number

This code will check the database for an order number. If none exist it creates one. If one does exist then it will increment it by one and update the database. Is this the most efficient way to ...
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147 views

Making backtracking Sudoku solver more functional

I'm implementing the backtracking solving algorithm for a Sudoku in F#. I'm wondering if I could make my code better respect the functional programming paradigm or even just making it simpler/better. ...
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91 views

Traffic Flow functional way

The same problem, but f# instead c#: ...
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1answer
89 views

SalesTax problem

The same problem, but I decided to do it using F#: ...
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1answer
70 views

Organizing types/namespaces within tree

I'm working on a parsing engine as part of a personal project, and I'd like to expose certain .NET APIs to the parsed environment. I put together a very simple tagged union that allowed me to nest ...
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1answer
171 views

Is this use of ConcurrentDictionary truly thread safe?

I'm working on some teaching examples showing the perils of accessing the Dictionary class concurrently. In the code below each function is designed to do a word count across a number of files. ...
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193 views

Check database for item and create it if it doesn't exist

Is there a more efficient approach to this code? ...
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0answers
81 views

Polling, parsing, validating and handling data cleanly and efficiently

<edit: There's a major problem in the code. It is basically the one in the comment regarding backpressure. I'll rework the code within a a few days... It's time for a quick code review, good ...
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2answers
102 views

A concurrency-safe stack structure

This is a teaching sample intended to illustrate use of mutability and list consing in F#. The structure is intended to be a thread-safe stack structure, which multiple threads can push to/pop from ...
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1answer
54 views

Server code to save uploaded files

This code basically saves an uploaded file to the server. I am wondering if there is anything that I can do to tighten this code up. I am very new to F# so I'm still having trouble breaking away ...
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1answer
188 views

NinjectWebCommon implementation/translation - C# to F#

I've translated this code from c# and would like it to be more idiomatic f#: ...
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1answer
165 views

Basic templating engine in F# using F# syntax

I've been working on a rough idea for a templating engine (mostly as a learning project) using the F# syntax. How "correct" is my code in terms of being idiomatic F#? Are there F# features which would ...
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4answers
317 views

Splitting a sequence into equal segments

I need to split up a sequence into equal segments of a given size (yes, the last one may be shorter), and I'm trying to find an efficient and idiomatic way to do it. I have two versions of the ...
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2answers
698 views

First real-world F# application - how “good”/idiomatic is it? (long!)

After reading/watching various introductions and blog posts and some code here and there, doing a bit of the Try F# tutorial and starting to read "Real World Functional Programming", I felt I should ...
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152 views

Simple RabbitMQ client wrapper

After reading this question, I've realized that I can do a lot to improve the quality of my question, so I've edited this question quite a bit. I've been teaching myself F# in my spare time off and ...