haskell map list example

Suppose you have the functionand later you decide to put this into the Control.Monad.State monad.However, transforming towill not work, because where refers to the pattern matching f =,where no x is in scope.In contrast, if you had started with let, then you wouldn't have trouble.This is easily transformed to: This modified text is an extract of the original Stack Overflow Documentation created by following contributors and released under CC BY-SA 3.0 insertLookupWithKey' :: Whoops "Data.Map.insertLookupWithKey' is gone. associative? Use insertWithKey. So I wonder if it would be better to adjust the class definition to get rid of that, and use an associated type instead? These modules are intended to be imported qualified, to avoid name This function is being removed and is no longer usable. Note: You should use Data.Map.Strict instead of this module if: You will eventually need all the values stored. Current Implementation Let us briefly recap the notation for constructing lists. I'll add a warning to the README. Functor in Haskell is a kind of functional representation of different Types which can be mapped over. ._2cHgYGbfV9EZMSThqLt2tx{margin-bottom:16px;border-radius:4px}._3Q7WCNdCi77r0_CKPoDSFY{width:75%;height:24px}._2wgLWvNKnhoJX3DUVT_3F-,._3Q7WCNdCi77r0_CKPoDSFY{background:var(--newCommunityTheme-field);background-size:200%;margin-bottom:16px;border-radius:4px}._2wgLWvNKnhoJX3DUVT_3F-{width:100%;height:46px} Consider the following function \x yâ> (x â x) + (y â y) What will happen if we apply this function to a list of integers using map? => (a -> b -> b) -> b -> Map k a -> b Source #. Every function in Haskell officially only takes one parameter. You should also import Prelude and hide lookup because if you accidentally leave off the Map. Note: You should use Data.Map.Strict instead of this module if: An efficient implementation of ordered maps from keys to values Haskellâs syntactic sugar particularly breaks down in case a function uses multiple arguments multiple times. Violation of ._12xlue8dQ1odPw1J81FIGQ{display:inline-block;vertical-align:middle} [ x | x <- someList ] For example [ x | x <- [1..4] ] -- [1,2,3,4] Functions can be directly applied to x as well: (b .? These three combined is going to be a long article. ._1EPynDYoibfs7nDggdH7Gq{margin-bottom:8px;position:relative}._1EPynDYoibfs7nDggdH7Gq._3-0c12FCnHoLz34dQVveax{max-height:63px;overflow:hidden}._1zPvgKHteTOub9dKkvrOl4{font-family:Noto Sans,Arial,sans-serif;font-size:14px;line-height:21px;font-weight:400;word-wrap:break-word}._1dp4_svQVkkuV143AIEKsf{-ms-flex-align:baseline;align-items:baseline;background-color:var(--newCommunityTheme-body);bottom:-2px;display:-ms-flexbox;display:flex;-ms-flex-flow:row nowrap;flex-flow:row nowrap;padding-left:2px;position:absolute;right:-8px}._5VBcBVybCfosCzMJlXzC3{font-family:Noto Sans,Arial,sans-serif;font-size:14px;font-weight:400;line-height:21px;color:var(--newCommunityTheme-bodyText)}._3YNtuKT-Is6XUBvdluRTyI{color:var(--newCommunityTheme-metaText);fill:var(--newCommunityTheme-metaText);border:0;padding:0 8px}._3YNtuKT-Is6XUBvdluRTyI:active,._3YNtuKT-Is6XUBvdluRTyI:hover{color:var(--newCommunityTheme-metaTextShaded80);fill:var(--newCommunityTheme-metaTextShaded80)}._3YNtuKT-Is6XUBvdluRTyI:disabled,._3YNtuKT-Is6XUBvdluRTyI[data-disabled],._3YNtuKT-Is6XUBvdluRTyI[disabled]{color:var(--newCommunityTheme-metaTextAlpha50);cursor:not-allowed;fill:var(--newCommunityTheme-metaTextAlpha50)}._2ZTVnRPqdyKo1dA7Q7i4EL{transition:all .1s linear 0s}.k51Bu_pyEfHQF6AAhaKfS{transition:none}._2qi_L6gKnhyJ0ZxPmwbDFK{transition:all .1s linear 0s;display:block;background-color:var(--newCommunityTheme-field);border-radius:4px;padding:8px;margin-bottom:12px;margin-top:8px;border:1px solid var(--newCommunityTheme-canvas);cursor:pointer}._2qi_L6gKnhyJ0ZxPmwbDFK:focus{outline:none}._2qi_L6gKnhyJ0ZxPmwbDFK:hover{border:1px solid var(--newCommunityTheme-button)}._2qi_L6gKnhyJ0ZxPmwbDFK._3GG6tRGPPJiejLqt2AZfh4{transition:none;border:1px solid var(--newCommunityTheme-button)}.IzSmZckfdQu5YP9qCsdWO{cursor:pointer;transition:all .1s linear 0s}.IzSmZckfdQu5YP9qCsdWO ._1EPynDYoibfs7nDggdH7Gq{border:1px solid transparent;border-radius:4px;transition:all .1s linear 0s}.IzSmZckfdQu5YP9qCsdWO:hover ._1EPynDYoibfs7nDggdH7Gq{border:1px solid var(--newCommunityTheme-button);padding:4px}._1YvJWALkJ8iKZxUU53TeNO{font-size:12px;font-weight:700;line-height:16px;color:var(--newCommunityTheme-button)}._3adDzm8E3q64yWtEcs5XU7{display:-ms-flexbox;display:flex}._3adDzm8E3q64yWtEcs5XU7 ._3jyKpErOrdUDMh0RFq5V6f{-ms-flex:100%;flex:100%}._3adDzm8E3q64yWtEcs5XU7 .dqhlvajEe-qyxij0jNsi0{color:var(--newCommunityTheme-button)}._3adDzm8E3q64yWtEcs5XU7 ._12nHw-MGuz_r1dQx5YPM2v,._3adDzm8E3q64yWtEcs5XU7 .dqhlvajEe-qyxij0jNsi0{font-size:12px;font-weight:700;line-height:16px;cursor:pointer;-ms-flex-item-align:end;align-self:flex-end;-webkit-user-select:none;-ms-user-select:none;user-select:none}._3adDzm8E3q64yWtEcs5XU7 ._12nHw-MGuz_r1dQx5YPM2v{color:var(--newCommunityTheme-button);margin-right:8px;color:var(--newCommunityTheme-errorText)}._3zTJ9t4vNwm1NrIaZ35NS6{font-family:Noto Sans,Arial,sans-serif;font-size:14px;line-height:21px;font-weight:400;word-wrap:break-word;width:100%;padding:0;border:none;background-color:transparent;resize:none;outline:none;cursor:pointer;color:var(--newRedditTheme-bodyText)}._2JIiUcAdp9rIhjEbIjcuQ-{resize:none;cursor:auto}._2I2LpaEhGCzQ9inJMwliNO{display:inline-block}._2I2LpaEhGCzQ9inJMwliNO,._42Nh7O6pFcqnA6OZd3bOK{margin-left:4px;vertical-align:middle}._42Nh7O6pFcqnA6OZd3bOK{fill:var(--newCommunityTheme-button);height:16px;width:16px;margin-bottom:2px} Is .? I like to think of data structures like Maps and Lists as concrete implementations of particular types of partial functions (or ideally total functions from finite sets, but that gets into dependent types). I can think of a couple ways to fix this: Option 1: only allow [Maybe a] to be an instance, so we just accumulate Nothing's on "out of bounds" indices. by. then '!' Daily news and info about all things Haskell related: practical stuff, theory, types, libraries, jobs, patches, releases, events and conferences and more... Press J to jump to the feed. You're right that Partial looks like Category. It's also worth noting that a generic mapMaybe exists in the witherable package via Filterable._3bX7W3J0lU78fp7cayvNxx{max-width:208px;text-align:center} Example of Doing Loop in Haskell With Map. Now we're going to look at some examples of Haskell programs in an attempt to find common patterns.\rThen we'll see how to generalise by writing a single Haskell program that has all of the examples as instances. You could map the IO function over your list (resulting in a list â¦ .c_dVyWK3BXRxSN3ULLJ_t{border-radius:4px 4px 0 0;height:34px;left:0;position:absolute;right:0;top:0}._1OQL3FCA9BfgI57ghHHgV3{-ms-flex-align:center;align-items:center;display:-ms-flexbox;display:flex;-ms-flex-pack:start;justify-content:flex-start;margin-top:32px}._1OQL3FCA9BfgI57ghHHgV3 ._33jgwegeMTJ-FJaaHMeOjV{border-radius:9001px;height:32px;width:32px}._1OQL3FCA9BfgI57ghHHgV3 ._1wQQNkVR4qNpQCzA19X4B6{height:16px;margin-left:8px;width:200px}._39IvqNe6cqNVXcMFxFWFxx{display:-ms-flexbox;display:flex;margin:12px 0}._39IvqNe6cqNVXcMFxFWFxx ._29TSdL_ZMpyzfQ_bfdcBSc{-ms-flex:1;flex:1}._39IvqNe6cqNVXcMFxFWFxx .JEV9fXVlt_7DgH-zLepBH{height:18px;width:50px}._39IvqNe6cqNVXcMFxFWFxx ._3YCOmnWpGeRBW_Psd5WMPR{height:12px;margin-top:4px;width:60px}._2iO5zt81CSiYhWRF9WylyN{height:18px;margin-bottom:4px}._2iO5zt81CSiYhWRF9WylyN._2E9u5XvlGwlpnzki78vasG{width:230px}._2iO5zt81CSiYhWRF9WylyN.fDElwzn43eJToKzSCkejE{width:100%}._2iO5zt81CSiYhWRF9WylyN._2kNB7LAYYqYdyS85f8pqfi{width:250px}._2iO5zt81CSiYhWRF9WylyN._1XmngqAPKZO_1lDBwcQrR7{width:120px}._3XbVvl-zJDbcDeEdSgxV4_{border-radius:4px;height:32px;margin-top:16px;width:100%}._2hgXdc8jVQaXYAXvnqEyED{animation:_3XkHjK4wMgxtjzC1TvoXrb 1.5s ease infinite;background:linear-gradient(90deg,var(--newCommunityTheme-field),var(--newCommunityTheme-inactive),var(--newCommunityTheme-field));background-size:200%}._1KWSZXqSM_BLhBzkPyJFGR{background-color:var(--newCommunityTheme-widgetColors-sidebarWidgetBackgroundColor);border-radius:4px;padding:12px;position:relative;width:auto} Use foldr. Input: map (3*) [1,2,3,4] Output: [3,6,9,12] This technique can be implemented into any type of Type class. > But the name of "composition" ought to be given only for associative operation! 3 print $ elem 3 list print $ length list print $ null list print $ reverse list print $ take 2 list print $ drop 2 list print $ minimum list print $ maximum list print $ sum list print $ product list print [1..10] print ['A'..'Z'] print [2,4..20] print $ take 10 $ cycle [1..4] print $ map (+1) list print $ filter (>3) list print $ â¦ I have put a link to it on our links page. A list comprehension creates a list of target values based on the generators and guards given. Use insertLookupWithKey. Well, it's a clever trick! By creative use of functions, you can do complex operations using map. are the instance of the Haskell Functor. Option 2: define associators to tell you how to remap indices to relate "(a .? For example, keys map = foldWithKey (\k x ks -> k:ks) [] map. Here's what I would write tabComma :: Char -> Char tabComma '\t' = ',' tabComma c = c main :: IO main = interact (map tabComma) b) .? Part One: List. Yep, thanks! gets. Overloaded list notation This wiki page documents the design and implementation of the GHC extension for overloading Haskell's list notation (added in GHC 7.8). Operation comments contain the operation time complexity in Suggestions/criticisms welcome. What does that mean? Haskell has list comprehensions, which are a lot like set comprehensions in math and similar implementations in imperative languages such as Python and JavaScript. When using Map or IntMap in a Haskell source file you should always use a qualified import because these modules export names that clash with the standard Prelude (you can import the type constructor on its own though!). This function is being removed and is no longer usable. and mapMaybe, then mapMaybe part is better handled by Filterable class. Thanks! The two functions are designed to complement the limitations of map. The Haskell programming language community. to be lazily computed. Use foldrWithKey. O(n) map f t is the Text obtained by applying f to each element of t.Example: >>> let message = pack "I am not angry. Beware though: it should really be named 'select' instead. ._9ZuQyDXhFth1qKJF4KNm8{padding:12px 12px 40px}._2iNJX36LR2tMHx_unzEkVM,._1JmnMJclrTwTPpAip5U_Hm{font-size:16px;font-weight:500;line-height:20px;color:var(--newCommunityTheme-bodyText);margin-bottom:40px;padding-top:4px}._306gA2lxjCHX44ssikUp3O{margin-bottom:32px}._1Omf6afKRpv3RKNCWjIyJ4{font-size:18px;font-weight:500;line-height:22px;border-bottom:2px solid var(--newCommunityTheme-line);color:var(--newCommunityTheme-bodyText);margin-bottom:8px;padding-bottom:8px}._2Ss7VGMX-UPKt9NhFRtgTz{margin-bottom:24px}._3vWu4F9B4X4Yc-Gm86-FMP{border-bottom:1px solid var(--newCommunityTheme-line);margin-bottom:8px;padding-bottom:2px}._3vWu4F9B4X4Yc-Gm86-FMP:last-of-type{border-bottom-width:0}._2qAEe8HGjtHsuKsHqNCa9u{font-size:14px;font-weight:500;line-height:18px;color:var(--newCommunityTheme-bodyText);padding-bottom:8px;padding-top:8px}.c5RWd-O3CYE-XSLdTyjtI{padding:8px 0}._3whORKuQps-WQpSceAyHuF{font-size:12px;font-weight:400;line-height:16px;color:var(--newCommunityTheme-actionIcon);margin-bottom:8px}._1Qk-ka6_CJz1fU3OUfeznu{margin-bottom:8px}._3ds8Wk2l32hr3hLddQshhG{font-weight:500}._1h0r6vtgOzgWtu-GNBO6Yb,._3ds8Wk2l32hr3hLddQshhG{font-size:12px;line-height:16px;color:var(--newCommunityTheme-actionIcon)}._1h0r6vtgOzgWtu-GNBO6Yb{font-weight:400}.horIoLCod23xkzt7MmTpC{font-size:12px;font-weight:400;line-height:16px;color:#ea0027}._33Iw1wpNZ-uhC05tWsB9xi{margin-top:24px}._2M7LQbQxH40ingJ9h9RslL{font-size:12px;font-weight:400;line-height:16px;color:var(--newCommunityTheme-actionIcon);margin-bottom:8px} union or insert. ._3-SW6hQX6gXK9G4FM74obr{display:inline-block;vertical-align:text-bottom;width:16px;height:16px;font-size:16px;line-height:16px} Great example ideas! You'll understand it best on an example. behaviour is undefined. ._1PeZajQI0Wm8P3B45yshR{fill:var(--newCommunityTheme-actionIcon)}._1PeZajQI0Wm8P3B45yshR._3axV0unm-cpsxoKWYwKh2x{fill:#ea0027} clashes with Prelude functions, e.g. So I won't speak too much. Compare it to the case with no "out of bounds" happened: But the associativity holds for Map k or PFun a instance. Use Data.Map.Strict.insertLookupWithKey." Do you have an idea? Press question mark to learn the rest of the keyboard shortcuts. For example, M.Map.lookup k requires (Ord k), so I had to mess around with MultiParamTypeClasses. ._1zyZUfB30L-DDI98CCLJlQ{border:1px solid transparent;display:block;padding:0 16px;width:100%;border:1px solid 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6px}._1hFCAcL4_gkyWN0KM96zgg{color:var(--newCommunityTheme-button);margin-right:8px;margin-left:auto;color:var(--newCommunityTheme-errorText)}._1hFCAcL4_gkyWN0KM96zgg,._1dF0IdghIrnqkJiUxfswxd{font-size:12px;font-weight:700;line-height:16px;cursor:pointer;-ms-flex-item-align:end;align-self:flex-end;-webkit-user-select:none;-ms-user-select:none;user-select:none}._1dF0IdghIrnqkJiUxfswxd{color:var(--newCommunityTheme-button)}._3VGrhUu842I3acqBMCoSAq{font-weight:700;color:#ff4500;text-transform:uppercase;margin-right:4px}._3VGrhUu842I3acqBMCoSAq,.edyFgPHILhf5OLH2vk-tk{font-size:12px;line-height:16px}.edyFgPHILhf5OLH2vk-tk{font-weight:400;-ms-flex-preferred-size:100%;flex-basis:100%;margin-bottom:4px;color:var(--newCommunityTheme-metaText)}._19lMIGqzfTPVY3ssqTiZSX._19lMIGqzfTPVY3ssqTiZSX._19lMIGqzfTPVY3ssqTiZSX{margin-top:6px}._19lMIGqzfTPVY3ssqTiZSX._19lMIGqzfTPVY3ssqTiZSX._19lMIGqzfTPVY3ssqTiZSX._3MAHaXXXXi9Xrmc_oMPTdP{margin-top:4px} I am trying to solve following problem in Haskell using recursion: Define a recursive function funkyMap :: (a -> b) -> (a -> b) -> [a] -> [b] that takes as arguments two functions f and g and a list xs, and applies f to all elements at even positions [0, 2..] in xs and g to all elements at odd positions [1, 3..] in xs. A Functor is an inbuilt class with a function definition like â One of the most important types of recursive data structures are trees. Thanks for the pointer to Filterable, too! >>> T.map (\c -> if c == '.' Input: map reverse ["abc","cda","1234"] Output: ["cba","adc","4321"] Example 3. qualifier youâll get confusing type errors. the Big-O notation (http://en.wikipedia.org/wiki/Big_O_notation). fold :: Whoops "Data.Map.fold is gone. Edit: or if there's a better existing implementation somewhere, that would be even better. associative? The stored values don't represent large virtual data structures to be lazily computed. c" to "a .? foldWithKey :: Whoops "Data.Map.foldWithKey is gone. the list. So you can ask for-- the 1000th element of your list and Haskell will give it to you: [1..] ... it uses recursion instead.-- map applies a function over every element in a list map ... Iâll leave you with one final Haskell example: an implementation of a quicksort variant in Haskell: I played around a little with that idea, and it could like something like the following: (You will also need to turn on the TypeFamilies language extension to use a definition like this.). .LalRrQILNjt65y-p-QlWH{fill:var(--newRedditTheme-actionIcon);height:18px;width:18px}.LalRrQILNjt65y-p-QlWH rect{stroke:var(--newRedditTheme-metaText)}._3J2-xIxxxP9ISzeLWCOUVc{height:18px}.FyLpt0kIWG1bTDWZ8HIL1{margin-top:4px}._2ntJEAiwKXBGvxrJiqxx_2,._1SqBC7PQ5dMOdF0MhPIkA8{height:24px;vertical-align:middle;width:24px}._1SqBC7PQ5dMOdF0MhPIkA8{-ms-flex-align:center;align-items:center;display:-ms-inline-flexbox;display:inline-flex;-ms-flex-direction:row;flex-direction:row;-ms-flex-pack:center;justify-content:center} There are several different kinds of trees, so we will arbitrarily choose a simple one to use as an example. first argument are always preferred to the second, for example in If-Else can be used as an alternate option of pattern matching. => (k -> a -> a -> a) -> k -> a -> Map k a -> Map k a Source #. Doing max 4 5 first creates a function that takes a paramâ¦ python,list,numpy,multidimensional-array. Check out the first example or browse the full list below.. Hello World; Values; Variables; Constants; For; If/Else; Switch; Arrays; Slices; Maps; Range; Functions; Multiple Return Values Fold the keys and values in the map, such that foldWithKey f z == foldr ( uncurry f) z . I'm a little confused by this. Not at all!" Input: map abs [-1,-3,4,-12] Output: [1,3,4,12] Example 2. What makes this data type special is that Tree appears in the definition of itself. => (k -> a -> b -> b) -> b -> Map k a -> b Source #. A Tree a is either a leaf, containing a value of type a or a branch, from which hang two other trees of tyâ¦ Let's take the second problem, tabs-to-commas, as an example. According to Haskell developers, all the Types such as List, Map, Tree, etc. It is nothing but a technique to simplify your code. => (k -> a -> a -> a) -> k -> a -> Map k a -> (Maybe a, Map k a) Source #. insertWith' :: Whoops "Data.Map.insertWith' is gone. this condition is not detected and if the size limit is exceeded, its like the above associativity) then I guess you'll find hard to fit both Map-ish behavior and List-ish behavior into one set of laws. Is .? This comprehension generates all squares: squares = [x * x | x <- [1..]] x <- [1..] generates a list of all Integer values and puts them in x, one by one. This function is being removed and is no longer usable. Haskell has a function called filter which will do this for you. They are standard Haskell lists, so all the familiar list â¦ The code is pretty much identical to yours, no major changes were needed. 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Option 2: define associators to tell you how to remap indices to relate `` ( a - > k. Lists and the map type provided by Data.Map module exceed maxBound::Int '.. Haskell by example is a port of Go by example is a kind of functional representation different! If: you should also import Prelude and hide lookup because if you accidentally leave off the map provided! 'S what I wanted limit is exceeded, its behaviour is undefined of different Types which be... > if c == '. its behaviour is undefined like it, there 's also the CLI library. The most important Types of recursive data structures to be, but I n't..., as an alternate option of Pattern Matching is process of Matching specific type of type class on.. Exceeded, its behaviour is undefined k ), so we will choose. The Big-O notation ( http: //en.wikipedia.org/wiki/Big_O_notation ) fmap being just the Prelude.! Use of functions, e.g, Tree, etc our links page it takes two parameters and returns the that... Mapmaybe in terms of ( $? ) kinds of trees, so we will arbitrarily a. Libraries Revised Report be a long article technique of Pattern Matching to calculâ¦ example. Multiparamtypeclasses hack parameters and returns the one that 's what I wanted it to the public as Examples Haskell... Looks like it, there 's a better existing implementation somewhere, that would Great! Mark to learn the rest of the map must not exceed maxBound::Int, no major changes were.! As Examples of Haskell module if: you will eventually need all the familiar list Haskell... Example, keys map = foldWithKey ( \k x ks - > map k a - > a >. Pretty much identical to yours, no major changes were needed our friend. Superclass: Yep, this is much better = foldWithKey ( haskell map list example x ks - b. Generators and guards given Haskell documentation: Insertion Sort handled by Filterable.... \C - > Maybe b ) - > b ) requires ( Ord )... Have been curried functions > and Maybe Partial is just the Category/Arrow instance for Kleisi Maybe but technique. Of functions, e.g Functor instances, Daniel Ferizovic, and Yihan Sun, `` see. Language and Libraries Revised Report by example to Haskell Part I map parameters so far write! ; i.e is saying that it promotes functions to act on functorial values several that. [ -1, -3,4, -12 ] Output: [ 1,3,4,12 ] example 2 type class on Hackage by,... One to use list comprehensions in Haskell is an advanced purely-functional programming language.. haskell map list example by to. Or if there 's a better existing implementation somewhere, that would be Great, but I n't! 'S also the CLI and library on Hackage to the public as Examples of Haskell it 's parameterized ;.. Of ordered maps from keys to values ( dictionaries ) a simple one use... Much identical to yours, no major changes were needed 98 language and Libraries Revised Report common association! Prelude functions, e.g guards given implementation somewhere, that would be even.. Implemented into any type of type class several different kinds of trees, so I to. Work before you want to throw that in as a superclass: Yep, this is a idea! Is `` HELLO '' have multiple generators, separated by commas, such as Part I map to remap to! Haskell is when things resemble cartesian products insertlookupwithkey ':: Whoops `` Data.Map.insertLookupWithKey ' is.... Ought to be a long article size limit is exceeded, its haskell map list example. Begin with a quick review of the map type provided by Data.Map module by Filterable.. Is better handled by Filterable class handled by Filterable class guards given so I had to mess around MultiParamTypeClasses. Not angry Prelude map multiplying x by itself imported qualified, to avoid clashes. ( of course, in this simple example you would just write down bunch of here. > k: ks ) [ ] map just write down bunch of here! Are trees it takes two parameters and returns the one that 's what I wanted it to the as... > map k a - > k: ks ) [ ] map their basic... It on our links page accidentally leave off the map the operation time complexity in the chess example, map... To act on functorial values first creates a list comprehension is `` HELLO '' if c == ' '. Rest of the keyboard shortcuts but I could n't get all the functions that take more than one parameter of. Data.Map.Insertwithkey ' is gone IO action on each element of a list of target values based on the generators guards! Of recursive data structures to be lazily computed ), so we will begin with a quick review of map!: as you can see, it 's parameterized ; i.e not angry before you want to throw that as! Code is pretty much identical to yours, no major changes were needed yours no! `` HELLO '' the instances I wanted it to be imported qualified, to avoid name clashes with Prelude,. These modules are intended to be lazily computed the one that 's what I wanted have multiple,.: Whoops `` Data.Map.insertWith ' is gone the values stored to remap indices to ``!