Fold (aka reduce) is considered a very important higher order function. Map can be expressed in开发者_运维百科 terms of fold (see here). But it sounds more academical than practical to me. A typical u
I wonder wh开发者_StackOverflow社区y scala.Option doesn\'t have a method fold like this defined:
For instance, i have a list like [\'a\',\'b\',\'c\',\'d\',\'e\']. I want to do something like this: First do something with the firs开发者_Python百科t two elements, f \'a\' \'b\'
Given a function: 开发者_运维技巧min(A, B)when A =< B -> A; min(_A, B)-> B. can I use this in the function foldlin a similar fashion to this:
I have a List defined as: val l = List(\"1\", \"2\", \"3\") I want to convert it to the string \"1:2:3\"
How can I write general开发者_如何学Cized foldr and foldl function for generic Haskell trees, given this definition?
How can I check if a BST is a valid one, given its definition and using a generalized version of fold for BST?
From prelude: foldl1: it takes the first 2 items of the list and applies the function to them, then 开发者_开发技巧feeds the function with
When dealing with sizeable algebraic data types in Haskell, there is a particular recursive traversal not captured by folding over the data type. For instance, suppose I have a simple data type repres
I am just curious if there are any (first order polymorphic only) optimisations with folds. For maps, there\'s deforestation开发者_运维知识库: map g (map f ls) => map (g . f) ls, and rev (map f ls
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