Composition of functions in F# is easily achieved by using the >> operator. You can also chain an arbitary amount of functions (represented as a list or sequence) together by folding the list/seq with >>. [More formally: the set of endomorphisms 'a -> 'a forms a monoid with the binary, associative operator ">>" (or "<<") and the neutral element "id".]
79 people like thisPosted: 8 years ago by Novox
This snippet is helpfull in the following cases: 1) After a consolidation operation using the fold function we need to know how many elements have been processed. 2) A consolidation operation needs to use the index of each of the elements processed and we don't want to use the mapi function first. 3) A combination of the above. Since the following snippet just adds a wrapper to the existing Fold function we can repeat the approach for arrays and sequences (including the plinq ones)
31 people like thisPosted: 8 years ago by Horacio Nuñez
An abstraction of the following use case: Given a sequence of dates and max temperatures for each date, extract out the initial dates on which the temp is greater than a given threshold for n consecutive days. (Originally posted as an answer to this StackOverflow question: http://stackoverflow.com/questions/5267055 )
13 people like thisPosted: 7 years ago by ildjarn
Let's have some fun with higher order functions and instead of folding over a list, fold over the prime factors of a number. It can be optimized further by dividing out real primes instead of numbers of the form 6k+/-1, but it's not embarrassingly slow.
2 people like thisPosted: 7 years ago by Arjen Kopinga
fold by applying a list of function to a list of arg, last one behaving as usual
1 people like thisPosted: 6 years ago by nicolas2
Shuffling array using Seq.fold
4 people like thisPosted: 4 years ago by Karlkim Suwanmongkol
@Samuel - saw your post and thought one part was similar to bit shifting I was playing with yesterday, so rewrote the FromBooleans function using a fold instead of ref cells. Probably not as readable as your version though :)
2 people like thisPosted: 4 years ago by Chris Ballard
Idea from Guy L. Steele - Organizing Functional Code for Parallel Execution; or, foldl and foldr Considered Slightly Harmful - https://vimeo.com/6624203
9 people like thisPosted: 4 years ago by Tuomas Hietanen
Generic Type-level Fold for Boolean Algebra
0 people like thisPosted: 3 years ago by Nick Palladinos
A SIMD enhanced fold function that adds on to the Array type
2 people like thisPosted: 2 years ago by Jack Mott
This snippet is code that solves first Project Euler problem. It finds the sum of all the multiples of 3 or 5 below 1000. Please add other (more efficient, succinct or interesting) solutions to this snippet.
72 people like thisPosted: 8 years ago by Eugene Gavrin
Three ways to split a list in half (but not necessarily in the middle). A forth version added that's very short and should be fast, as we only use List.fold. New champ found.
77 people like thisPosted: 7 years ago by Dmitri Pavlenkov
Seq.sumBy implemented in terms of Seq.fold
2 people like thisPosted: 7 years ago by ildjarn
Calculating the Earth Similarity Index of a planet. http://phl.upr.edu/projects/earth-similarity-index-esi
0 people like thisPosted: 6 years ago by Kit Eason
A random pex4fun puzzle to write a snippet to merge two strings.
2 people like thisPosted: 6 years ago by Joel Huang
Creates a map containing each item and its frequency as a key/value pair. Then sort by value in reverse order before printing each item.
1 people like thisPosted: 4 years ago by Bjørn Bæverfjord
Playing with simplified domain modules and event sourcing in F#
5 people like thisPosted: 4 years ago by mavnn
Fibonacci nth term with fold
6 people like thisPosted: 3 years ago by Andriy Tolstoy
A prototype of an associative fold operation when the function passed in arguments is a Semigroup(*) Operation. (*) Semigroup from Abstract Algebra.
2 people like thisPosted: 2 years ago by Fabio Galuppo