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Functional Programming: Get new Map from existing Map with changed value


Functional Programming: Get new Map from existing Map with changed value

By : 圣光七仔
Date : November 20 2020, 04:01 AM
wish of those help I have one map like , Why not simply use,
code :
val dataMapToUse = strMap.map{case(k,v) =>(k -> Data(v))}


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Java Functional Programming: How to convert a if-else ladder inside for loop to functional style?

Java Functional Programming: How to convert a if-else ladder inside for loop to functional style?


By : Lardher
Date : March 29 2020, 07:55 AM
Any of those help The question title is quite broad (convert if-else ladder), but since the actual question asks about a specific scenario, let me offer a sample that can at least illustrate what can be done.
Because the if-else structure creates three distinct lists based on a predicate applied to the item, we can express this behavior more declaratively as a grouping operation. The only extra needed to make this work out of the box would be to collapse the multiple Boolean predicates using a tagging object. For example:
code :
class Item {
    enum Category {A, B, AB}

    public Category getCategory() {
        return /* ... */;
    }
}
Map<Item.Category, List<Item>> categorized = 
    items.stream().collect(Collectors.groupingBy(Item::getCategory));
Functional Programming: is foldLeft is the parent method of all functional methods such as foldRight, map, filter

Functional Programming: is foldLeft is the parent method of all functional methods such as foldRight, map, filter


By : Andres Campos
Date : March 29 2020, 07:55 AM
hop of those help? In general, no, foldLeft is not the "father" of all other methods, because there are many collections other than List. For example, you can not implement Stream.map via Stream.foldLeft because foldLeft does a full traversal but map should not traverse the stream because of its laziness (it can be potentially infinite).
As to the List you are mostly right. However, some methods will be extremely inefficient if implemented via foldLeft. Consider list.drop(1). It should just return the tail of the list, but foldLeft would do a full traversal.
React vs ReactX vs Functional Programming vs Reactive Functional Programming vs Reactive Extensions

React vs ReactX vs Functional Programming vs Reactive Functional Programming vs Reactive Extensions


By : Sunil gauswami
Date : March 29 2020, 07:55 AM
should help you out Functional Programming: Very broad category. An approach to programming that can be used both in “traditional” languages or specialized functional languages. Main point is to minimize state and program without side-effects, preferably using “pure” functions in the mathematical sense, where a function return value is determined just by its arguments. Functional Reactive Programming: A style of structuring programs where the computation is driven by incoming events or signals. React: A JavaScript UI framework inspired both by functional programming and functional reactive programming. Its main point is to replace the tedious and error-prone DOM tree management with an automated algorithm driven by model updates. ReactX: No idea.
Functional Programming: How to handle exceptions in Functional Programming or what is its equivalent

Functional Programming: How to handle exceptions in Functional Programming or what is its equivalent


By : Rakesh Yadav
Date : March 29 2020, 07:55 AM
I wish this helpful for you The following shows how you could do it in Haskell.
Based on the type siginure divide :: Int -> Int -> Either [Char] Int you can see that the function divide will return either a Left string or a Right Int.
code :
divide :: Int -> Int -> Either [Char] Int
divide dividend divisor
    | (divisor == 0) = Left "Sorry, 0 is not allowed :o"
    | (dividend == (minBound :: Int)) && (divisor == -1) = Left "somethig went wrong"
    | otherwise = Right (dividend `div` divisor)


main = do
    print (divide 4 2)                     -- Right 2
    print (divide 4 0)                     -- Left "Sorry, 0 is not allowed :o"
    print (divide (minBound :: Int) (-1))  -- Left "somethig went wrong"
Is this statement true that Java 8 provides functional style but is not functional programming?

Is this statement true that Java 8 provides functional style but is not functional programming?


By : pati1892
Date : September 28 2020, 04:00 AM
this one helps. Here is a (non-exhaustive) list of abstract FP concepts:
Focus on immutability Referential transparency for functions Limitations on side effects (follows from 1 & 2) Expression-based, no statements. Statements are not first-class. Functions as first-class values. State changes as first-class values (e.g. Clojure atoms). Algebraic Data Types as fundamental units. Enforcing some or all of the above via the type system.
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