November 2018 1HaskellADay Problems and Solutions

• November 27th, 2018: Tuesday brings a little more logic to today's #haskell puzzler. 
  
• November 26th, 2018: Monday's #haskell problem: J'ACCUSE! 
• November 23rd, 2018: A little late, but here's a little logic puzzle to solve using #haskell on a frigid Friday. That took a couple of iterations, but BOOM! a #haskell solution to Friday's little logic puzzle. 
  
• November 22nd, 2018: Thursday's #haskell problem is from @fermatslibrary: we throw enough 1/4th together and we get 1/3. Trust me on this one. 
  
• November 21st, 2018: From @fermatslibrary comes Wednesday's #haskell problem For Wednesday's #haskell solution: π and e as an equality? How transcendent! ... eheh. 😎 
  
• November 5th, 2018: Monday's #haskell problem: rectangular numbers from a calculator face are all divisible by 11. True? The #haskell solution shows that yes, it is true! 
  
   
• November 2nd, 2018: From @fermatslibrary comes Friday's #haskell problem: twoSquaresDifference of any odd number. Friday's #haskell solution we are folding odd numbers to find their diff squares. 

October 2018 1HaskellADay Problems and Solutions

• October 31st, 2018: A Happy Halloween arithmetic puzzle for you Happy Haskellers! 
• October 25th, 2018: Thursday's #haskell problem we have a (Loopful) compiler for BF* Thursday's #haskell solution: A BF* compiler, blocks of code in loops working. 
• October 24th, 2018: Wednesday's #haskell problem: Thus we enter the Turing Tarpit! The solution to Wednesday's #haskell problem is a BF* (loopless) interpreter that prints out "Hello, world!" I didn't think I could reach the pinnacle of programming in my lifetime, yet, here I am. 😎 
• October 19th, 2018: For Friday's #haskell problem we look at patterns in how people define categories: a little knowledge management. 
  
• October 17th, 2018: For Wednesday's #haskell problem we are using Haskell to automate writing a set of SQL INSERT statements. The function addDays to Wednesday's #haskell problem's rescue! 
  
• October 15th, 2018: Monday's #haskell problem is a little asset shell-game. A little Set.union, a little Set.difference, to get today's #haskell solution. 
• October 9th, 2018: Tuesday's #haskell problem: given a set of ids and our knowledge store from yesterday, determine the status of the new ids. Tuesday's #haskell solution: a Set to determine membership, and a Map to give the result, with a little bit of Frege-logic for fun! 
• October 8th, 2018: Monday's #haskell problem is random screening (okay: predetermined screening). Monday's #haskell solution: indexing into a list often? Consider the Array-type. 
• October 5th, 2018: Friday's #haskell problem we create a workflow to process chunks of files as SQL INSERT statements. And lo! and behold! A #haskell solution to all our problems... or today's problem, anyway. 
  

August 2018 1HaskellADay problems and solutions

• August 22nd, 2018: For Wednesday's #haskell problem we query a directory and massage some JSON: all in a day's work. Wednesday's #haskell solution: Processing JSONs ... LIKE A BOSS! 
• August 20th, 2018: For Monday's #haskell problem we distill UUIDs encoded in news media URLs. Monday's #haskell solution uses the break function FTW! 
• August 16th, 2018: For Thursday's #haskell problem we have Zipf's Law and words-in-sentences: a [The Current Year] analysis. 
• August 15th, 2018: For Wednesday's #haskell problem, we look at the 5000 most frequently used English words and do a bit of analysis. Wednesday's #haskell solution gets us the top 5000 English language words and their counts. 
• August 3rd, 2018: For Friday's #haskell problem we ingest JSON to discover its structure. 

July 2018 1HaskellADay Problems and Solutions

• July 31st, 2018: Tuesday's #haskell problem: let's start to build a #kakuro-solver! YES! (Image via http://www.menneske.no/kakuro)

• July 30th, 2018: For Monday's #haskell problem we are looking at merging databases. Monday's #haskell solution is a Set.intersection, and we see the shared data tables of the two databases. 
• July 24th, 2018: For Tuesday's #haskell problem we are discovering a JSON dictionary structure and pruning away non-entries. A little JSON dictionary exploration with #haskell gets us to our solution today. 
• July 17th, 2018: For Tuesday's #haskell problem we parse bits o' data from more extensive JSON.
• July 11th, 2018: Wednesday's #haskell problem is going from an 'iffy' JSON structure to PERFECT (well: less 'iffy') JSON structure. 
• July 10th, 2018: For Tuesday's #haskell problem we explore and structure illtempered JSON. When JSON looks normal, but it's not quite, you call ... AESON on wings of eagles for Tuesday's #haskell solution. 
• July 9th, 2018: In Monday's #haskell problem we discover structure in mondo JSON. Monday's #Haskell solution revealed itself in the first 300 characters of prettiness! 
• July 3rd, 2018: For Tuesday's #haskell problem we translate the graph-like JSON to a set of relations, viewable in a graph database.  For Tuesday, #haskell's graph-solution using Relation values and, ooh! pretteh pictures! 
  

June 2018 1HaskellADay Problems and Solutions

• June 29th, 2018: Friday's #haskell problem is partially parsing a very large file. For Friday's #haskell solution we parse a JSON map by hand. 
• June 27th, 2018: In Wednesday's #haskell problem, we parse JSON ... TWICE! to get to the underlying graph structure. Wednesday's #haskell solution is a little bit (a lot, actually) of JSON parsing, and then some graph analysis.
• June 26th, 2018: Tuesday #haskell problem converts a .properties file to JSON to make a REST call. Converting a .properties file to JSON in 23,952 easy steps for Tuesday's #haskell solution. 
• June 25th, 2018: Monday's #haskell problem is parsing a JSON error report and updating the JSON with new information. In Monday's #haskell solution, we get a little 'lens-y' to update JSON data. 
• June 22nd, 2018: Friday's #haskell problem sends articles-as-JSON to an AWS Lambda function for processing. 
• June 20th, 2018: Wednesday's #haskell problem is SymbolTable from a set of articles, then document vectors. 
• June 19th, 2018: We find out that 'materially' is the word for Tuesday's #haskell problem. For Tuesday's #haskell solution we find that parsing JSON is simpler than parsing TSV. This comes as a surprise to no one but me. 
• June 18th, 2018: Monday's #haskell problem asks: "When are unique IDs not unique IDs?" More dater-analyses. Monday's #haskell solution: we go from 2300+ duplicates to 30+ duplicates. A good day's work. 
• June 15th, 2018: Friday's #haskell problem is sorting and removing duplicatesfrom a data table by defining Ord. Friday's #haskell solution removes duplicate articles by ID... but are the articles duplicates? Hmmmm! 
• June 8th, 2018: "Dater-analytics" is the name of the game for Friday's #haskell problem. You get some real-world dater that's yucky, and you get to unyuckify it. You're welcome. 
• June 6th, 2018: Now we take that restructured JSON (see yesterday's exercise) and store that JSON in a PostgreSQL database for Wednesday's #haskell exercise. Wednesday's #haskell solution populates entities with wikipedia reference into a PostgreSQL database. 
  
• June 5th, 2018: Tuesday's #haskell problem is to transform 'pancake' JSON into ... '3-layer cake'-JSON? Sure. #nailedit Tuesday's #haskell solution we restructured JSON and saved result to ... JSON! YAY! 
• June 4th, 2018: Monday's #haskell problem: interlanguage communication via the function main. 3 + 4 = 7 ... now do that and have Python talking to Haskell. 

May 2018 1HaskellADay Problems and Solutions

• May 31st, 2018: In Thursday's #haskell problem we are analyzing JSON so we can produce ... MORE JSON! And thus grows our Big Data. Thursday's #haskell solution shows us the results of Big Data analytics? More Big Data. YES! 
• May 30th, 2018: Wednesday's #haskell problem we process 'big-ish' data. Wednesday's #haskell solution: You take your big(-ish) data, and you chart it. THIS WE CALL DATA SCIENCE! 
  
• May 25th, 2018: Friday's #haskell problem is load testing a web application with a database pull. Friday's #haskell solution: a load-tester in Haskell! AHA! 😎
• May 24th, 2018: Thursday's #haskell exercise is adding articles to be cleaned up, post-ETL, to a dirty table in PostgreSQL. Thursday's #haskell solution stages articles loaded into the database to be cleaned up later. 
  
• May 21st, 2018: Monday's #haskell problem is to insert NEW (triaged) articles into a PostgreSQL database. 
• May 18th, 2018: Friday's #haskell exercise: there seems to be a lot of tagged terms for articles. Download these terms-as-JSON from a REST endpoint and count them is today's exercise. Friday's #haskell solution has got me singing "Havana-na-na-na!" ... no, wait: I meant: "uploading tags from a REST endpoint to a PostgreSQL database." That's what I meant. 
• May 17th, 2018: Thursday's #haskell exercise is to add database update functionality to existing code and in a Writer/IO monad; yikes! Thursday's #haskell solution: from the triaged articles, the update SQL statements naturally fall out. 
• May 11th, 2018: Friday's #haskell exercise: bridging Python and Haskell to deliver a polyglot system. 
• May 8th, 2018: Tuesday's #haskell problem uses articles fetched from a REST endpoint and article metadata to triage articles for daily upload to a PostgreSQL database. Tuesday's #haskell solution... triage: get! 
• May 7th, 2018: Monday's #haskell problem is extracting metadata for articles stored in a PostgreSQL database. Monday's #haskell solution repurposes a library to fetch article metadata from a new article database. 
  
• May 4th, 2018: For Friday's #haskell problem we look at a daily upload process from a REST endpoint to a SQL data store and start to implement it. Friday's #haskell solution gets a week's worth of data from the REST endpoint. 

April 2018 1HaskellADay Problems and Solutions

• April 25th, 2018: For Wednesday's #haskell problem we prove, definitively, @fermatslibrary n^5 is n ... for very small n. For Wednesday's #haskell solution we learn that number theory is so cool! 
  
• April 24th, 2018: For Tuesday's #haskell problem we look for a fix-point of simplifying HTML. Good thing it's not NP-hard! ... no ... wait. Tuesday's #haskell solution is the fix-point for HTML. Just like the fix-point for factorial. Structurally, maybe, but otherwise, kinda not. 
• April 23rd, 2018: What happens when things go wrong? We start to look at debugging for Monday's #haskell problem. For Monday's #haskell solution: the error is not here; the error is in another castle. 
  
• April 20th, 2018: Friday's #haskell problem is to decode HTML entities from titles of articles. Friday's #haskell solution: deHTMLification: get 
• April 18th, 2018: Hey! Let's store the raw JSON as a fall-back should our ETL process fail for Wednesday's #haskell problem. Wednesday's #Haskell solution: storing raw JSON in a SQL data store BECAUSE WE CAN! 
  
• April 17th, 2018: For Tuesday's #haskell problem we upload articles from a different publisher of a compressed JSON archive with a different format. We find adding a differently-structured set of articles to IxArt store is simple for Tuesday's #haskell solution. 
• April 16th, 2018: For Monday's #haskell problem, we take articles-as-json from various sources and put them into a common SQL data store. For Monday's #haskell solution we upload articles from different publications to a common SQL data store, both compressed and uncompressed archives. 
  
• April 13th, 2018: Friday's #haskell problem is to grab packets of articles from a REST endpoint for later processing. Friday's #haskell solution: Those are some rather large packets downloaded from the REST endpoint! 
• April 12th, 2018: Thursday's #haskell problem: auditing and logs. Thursday's #haskell solution is to wrap packet extraction and insertion in an ETL process. 
  
• April 11th, 2018: Wednesday's #haskell problem: when we download packets of articles, let's record that event. Wednesday's #haskell solution: we're inserting packets into our new database. 
  
• April 10th, 2018: Tuesday's #haskell problem: 🎵 "Does anybody know what time it is?" 🎶 (bonus: name that tune) Tuesday's #haskell solution: "Hey, Mister! You got the time?" 
• April 9th, 2018: Monday's #haskell problem is to extract article tags from JSON then store them in a PostgreSQL lookup table. Monday's #haskell solution: Inserting tags for articles into a PostgreSQL database is a breeze! 
  
• April 6th, 2018: Friday's #haskell problem is to parse categories-as-JSON, strip it down to its essentials, and store in a PostgreSQL data table. Friday's #haskell solution uploaded categories to a PostgreSQL databse after 'removing the stupid.' That's a technical term. 
  
  
• April 5th, 2018: Thursday's #haskell problem is revising the database connector now that we're managing multiple databasen. Thursday #haskell solution is making connections to SQL databases configurable. Whoa. Edgy, tweeps! I'm really pressing the bleeding edge of technological advancement here with configurations and database connections. 
• April 4th, 2018: Wednesday's #haskell problem is storing authors in a PostgreSQL table. Wednesday's #haskell solution shows that transferring authors from articles to a SQL database is as easy as 1, 2, 3! 
  
  
• April 3rd, 2018: Tuesday's #haskell exercise: AUTHOR! AUTHOR! Is there an author in the house? Tuesday's #haskell solution: extracting author information from very unstructured data. 
• April 2nd, 2018: Monday's #haskell problem is to explore JSON to find the structure in the data. Monday's #haskell solution: oooh! Pritteh JSON! But what's this weirdness with the author-identifier? 
  

February 2018 1 Liner 1HaskellADay Problems and Solutions

• February 8th, 2018: We have maybe :: b -> (a -> b) -> Maybe a -> b. But we don't have list? Or do we? Define list:
  list :: b -> ([a] -> b) -> [a] -> b
  list nullanswer flist lst = undefined
• BONUS: Both Maybe a and [a] are binary types, ... so is MonadPlus:
  
  Maybe a = Nothing | Just a
  List a = Cons a (List a) | Nil
  MonadPlus m => mzero | m a `mplus` m a
  
  Is there some generalization that maybe and list are functions of? What is that generalization?
• February 6th, 2018:
  You have f :: a -> [b] -> [c]
  But instead of just one a you have [a]
  Define g :: [a] -> [b] -> [c]
  in terms of f
• Daniel @leptonyu g as bs = foldl (\xs a -> f a bs ++ xs) [] as
• ptdr_bot @m0rth0n g as bs = flip f bs =<< as
• Victoria C @ToriconPrime g as bs = concat $ fmap ($ bs) (fmap f as)
• matt @themattchan g = flip $ concatMap . flip f
• Nicoλas @BeRewt g = flip (flip (>>=) . flip f) Or: g as bs = as >>= flip f bs
• Sangeet Kar @sangeet_kar g = foldMap f

March 2018 1HaskellADay problems and solutions

• March 14th, 2018: Wednesday #haskell problem I am thinking about sumaSumasCuadradosDivisores from the Haskell community via @Jose_A_Alonso 
• March 12th, 2018: Monday's #haskell problem is Improving Tarski's logic language with curried functions. 
• March 8th, 2018: For Thursday's #haskell problem, thanks to @wtfunctional, we'll play with Other People's Code! ... and Mandelbrot sets. 
  
• March 6th, 2018: Tuesday's #haskell exercise asks the eternal question: "Are you my mom?"... and also looks at curried functions in a logic framework... which is nice. Last Tuesday's #haskell solution ended in pathos: I know 'momOf', but I cannot answer, 'are you my mom?' Can you not feel the sads? 
• March 5th, 2018: Monday's #haskell problem is a little "Introduction to Logic" by Tarski to start our week of right. I went a little 'forall' in the #haskell solution today. Sorry. #notsorry 
  

February 2018 1HaskellADay problems and solutions

• February 28th, 2018: Wednesday's #haskell problem: (sung:) Ya know that I love Casey's Mom! (guitar wails) Wednesday's #haskell solution we solve with LOGIC PROGRAMMING! ... IN HASKELL! YES! 
• February 27th, 2018: Tuesday's #haskell problem: A job scheduling problem, posed by Mensa, answered by Haskell. Tuesday's #haskell solution is this lcm/scan-like function, because "... the work is never done." 
• February 22nd, 2018: Thursday's #haskell problem is counting in Haskell IN YOUR NATIVE LANGUAGE! 
• February 21st, 2018: Wednesday's #haskell problem is sorting lists and making list-o-lists from lists, via P99 and random.org because my love-affair with #Prolog. *ahem* (pure) Prolog. Wednesday's #haskell solution: lsort and lfsort, provided to you by sortOn and by @bazzargh and @xgrommx 
• February 20th, 2018: Tuesday's #haskell problem: More fun with elements in a list! Whee! Tuesday's #haskell solution: the monad-y approach, with alternatives by @xgrommx @bazzargh @johannesweiss 
• February 19th, 2018: Monday's #haskell exercise is from @fermatslibrary: permutable primes. Monday's #haskell solution: Primes. Permutable. ... #PWND! 

• February 16th, 2018: For Friday's #haskell problem P99 Prolog problem 33, coprime numbers with an assist by random.org. Friday's #haskell solution is coprimes: as easy as you please! 
  
• February 15th, 2018: Thursday's #haskell problem is the greatest common denominator via P99 Prolog problem set. For today's #haskell solution I'VE JUST (re)INVENTED GCD! KNEEL BEFORE ZOD! 
• February 14th, 2018: For Wednesday's #haskell problem: "I'm thinking of a word that has the letter 'V' ..." Happy Valentine's Day ... as an anagram! Today's #haskell solution was defined with ALACRITY! YUS! 
• February 13th, 2018: Tuesday's #haskell problem: we have unicode, and we could parse that as Text, but why do that when they want plain, old ASCII? ... why, indeed! Removing non-ASCII characters from documents is one approach to parsing them... 
• February 12th, 2018: A little CSV to JSON work via #haskell today. Monday's #haskell solution: 🎵 You say CSV, I say JSON. Let's call the whole thing off! 🎵 
• February 9th, 2018: Logs get stale, quickly! Let's archive old log entries for Friday's #haskell problem... so quickly, in fact, that the Friday's #haskell solution archived 270k+ rows of log entries! 
• February 7th, 2018: So, we will update articles in our PostgreSQL data store, but what happens when your codec is LATIN1 and you need to store the article as UTF8? Wednesday's #haskell problem. Wednesday's #haskell solution: TFW the exercise is an update function, but the solution goes whole-hog! smh 🙄 
• February 6th, 2018: Tuesday's #haskell problem is timestamping packets and associating articles with the packets that downloaded them. Tuesday's #haskell solution: associating the articles we uploaded TODAY with the packet we uploaded TODAY! 
• February 5th, 2018: On #SuperBowlSunday I release Monday's #haskell problem which is to timestamp log entries, because that's what we live for. Today's #haskell solution was a stunning victory by the Philadelphia Eagles ... no, ... wait: it was log entries, timestamped. There. #nailedit 
  
  
  
  
• February 2nd, 2018: We've downloaded a the most recent set of articles from a REST endpoint; now we have to exclude Associated Press articles from our local paper's set. Friday's #haskell problem. Today's #haskell solution filters out Associated Press articles from out downloaded article-set. 
• February 1st, 2018: Thursday's #haskell problem is from a picture posted from @fermatslibrary: anagrams as prime-multiples. Teacher: Class the following words are all English words: "Elaps lapse Lepas Pales salep saple sepal slape spale speal" Class: ... <<- a="" haskell="" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgN14nLdE2N0f2Zonc4xiXS9QwTY6ZiCvibeBzWRFL3szla11GYssWss4Isip5EOAyig2nAGzc8T2JSUP2iEC3AJbfknerzXflXeO_Y9CSfweII2Wwb_PXNxSoAcBXMZvqhWB7FFREgKsYT/s1600/anagram-by-primes.jpg" imageanchor="1" no="" s="" solution.="" style="color: #7d181e; margin-left: 1em; margin-right: 1em; text-decoration: none;" words.="" yesterday="">

January 2018 1Liner 1HaskellADay problems and solutions

• January 8th, 2018: from Nicoλas‏ @BeRewt
  A small @1HaskellADay, old-school. Define foo:
  
  > foo 3 [1..5]
  [([1,2,3], 4), ([2,3,4], 5)]
  
  > foo 2 [1..4]
  [([1,2], 3), ([2,3], 4)]
  
  > foo 2 [1..20]
  [([1,2],3), ([2,3],4), ..., ([18,19],20)]
  
  > foo 20 [1..2]
  []
• Demiurge With a Teletype @mrkgrnao
  foo n
    = tails
    # filter (length # (> n))
    # map (splitAt n # second head)
  
  (#) = flip (.)
• Andreas Källberg @Anka213
  I haven't tested it, but this should work:
  foo n xs = [ (hd,x) | (hd , x:_) <- n="" splitat=""> tails xs ]
• <- n="" splitat="">Nicoλas @BeRewt foo n = zip <$> fmap (take n) . tails <*> drop n
• January 5th, 2018: You have the following DAG-paths:
  
  a -> b -> c -> e
  a -> b -> d -> e
  q -> r -> s
  w -> x
  y -> z
  
  and many more.
  
  From a path, provide a bi-directional encoding* given maximum graph depth is, say, 7, max number of roots is, say, 10, and max number of nodes is, say, 1000.
• *bi-directional encoding of a graph path:
  
  DAG path -> enc is unique for an unique DAG path
  enc -> DAG path yields the same DAG path that created the unique enc.
  
  *DAG: "Directed, acyclic graph."
• January 5th, 2018: given s :: Ord k => a -> (k,[v])
  
  define f using s
  
  f :: Ord k => [a] -> Map k [v]
  
  with no duplicate k in [a]
• Christian Bay @the_greenbourne f = foldr (\e acc -> uncurry M.insert (s e) acc) M.empty
• me: you can curry away the acc variable easily
• Christian Bay @the_greenbourne You're right :)
  f = foldr (uncurry M.insert . s) M.empty
• Bazzargh @bazzargh fromList.(map s) ?
• me: Yuppers

January 2018 1HaskellADay Problems and Solutions

• January 30th, 2018: For Tuesday's #haskell problem we look at triaging articles downloaded from a REST endpoint against our PostgreSQL database. Who knew putting things into three bins could be so much fun? Today's #haskell solution triages work for us. 
• January 29th, 2018: Monday's #haskell problem is to fetch when the last set of articles were stored; two approaches. Monday's #haskell solution: two approaches to extract 'last entry' from the database, wanted; two approaches to extract 'last entry' from the database, GOT! 
• January 26th, 2018: Friday's #haskell problem is to pull a week's worth of data from a REST endpoint when we don't know a priori how many calls we have to make. Friday's #haskell solution fetches then reads/parses blocks of articles from a REST endpoint. 
• January 24th, 2018: Wednesday's #haskell problem is solving three more #Prolog-y list problems from P99: pack / encode / decode. It's great when #haskell has grouping / 'un'grouping functions in the library already. 
• January 23rd, 2018: Tuesday's #haskell problem: groups and grouper ... I like grouper blackened, please! Solving today's #haskell problem with Qubits?!? Nah, not really, but that would be cool if we did! 
  
• January 22nd, 2018: Monday's #haskell problem is a problem from P99: problem P21, list insertion. Monday's #haskell solution is inserting an element into a list, PROLOG-STYLE! 
• January 18th, 2018: The whole enchilada! Today's #haskell problem ties it all together to make an ETL. Today's #haskell solution defines etl: Looping over calls to the REST endpoint then database insertions. 
• January 17th, 2018: For today's #haskell problem we use PostgreSQL data store and Haskell to pick up where we left off on an application run. Today's #haskell solution: the audit log has what our program last did, so now we know what we'll work on next! 
• January 16th, 2018: Where did yesterday's Haskell problem go? Here it is! Today's #haskell problem: read a packet from a REST endpoint. Today's #haskell solution accesses a REST endpoint with a set timeout and with the default timeout.
• January 15th, 2018: "Logging? Why do we have to log stuff?" Enterprise applications require audit trails. Today's #haskell problem provides one. What did your Haskell app do and when? Today's #haskell solution: an audit log. 
  
• January 11th, 2018: Thursday's #haskell problem: pulling SQL lookup tables into Haskell. Thursday's #haskell solution: with the help of IxValues we extract lookup table values from SQL into Haskell Maps. 
• January 10th, 2018: Wednesday's #haskell exercise is to store the packet information into the PostgreSQL database as a part of auditing the ETL process. Wednesday's #haskell solution stores the packets that wrap article sets then logs our results. 
  
• January 9th, 2018: Tuesday's #haskell problem we are logging log messages to the log data table. YES! Tuesday's #haskell solution: logging in the style of log4j. 
• January 8th, 2018: Monday's #haskell problem: once more into the breach, and thoughts on generalization – storing unique newspaper article sections in PostgreSQL. We store article section information, then we build a function that stores ANYTHING! ... and washes windows, TOO! *
  
  *YMMV additionaltermsandconditionsmayapplydependingonyourregion 
• January 5th, 2018: Friday's #haskell problem takes a break from SQL Databases and Haskell and does something completely different: data schemes and Haskell. AHA! Friday's #haskell solution is a graph-view of the sections for a sample of 100 articles. 
  
• January 4th, 2018: Thursday's #haskell problem looks at storing in PostgreSQL authors of periodic articles uniquely identified by uuid. Thursday #haskell solution uses etl function with generators to store parsed authors in PostgreSQL database. 
  
  
  
  
• January 3rd, 2018: Wednesday's #haskell problem is in honor of Baron Munchausen and his fantastic adventures! 
• 
• January 2nd, 2018: WELCOME TO THE NEW YEAR, HASKELLERS!
  
  Tuesday's #haskell problem leverages keywords-as-subjects and makes storing article keywords into PostgreSQL easier... we hope. Tuesday's #haskell solution Incorporates prior work with memoizing tables and subjects with results. 
  

December 2017 1HaskellADay 1Liners problems and solutions

• December 29th, 2017:
  given f :: Monad m => n -> a -> m (Maybe b)
  define g :: Monad m => n -> a -> m (a, Maybe b)
  using f and ... arrows? Kleisli category?
• Bazzargh @bazzargh (\n a->liftM ((,) a) (f n a)) ... according to pointfree.io, that's `liftM2 fmap (,) . f` but I can't pretend to get the transformation
• December 29th, 2017:
  given f :: a -> b
  define g :: [a] -> [Maybe c] -> [(b, c)]
  
  >>> g [1,2,3] [Just 7, Nothing, Just 10]
  [("1",7),("3",10)]
  
  when f = show
• matt @themattchan
  g = catMaybes ... zipWith (fmap . (,) . f)
  where (...) = (.).(.)
• garrison @GarrisonLJ g a b = map (f.id***fromJust) . filter (isJust . snd) $ zip a b
• TJ Takei @karoyakani g = (catMaybes .) . zipWith ((<$>) . (,) . f)
• December 29th, 2017: define f :: [(a,b)] -> ([a], [b])
• Андреев Кирилл @nonaem00 and matt @themattchan unzip
• Victoria C @ToriconPrime f = fmap fst &&& fmap snd
• (in a vacuum, a more general type signature would be inferred, but the compiler limits itself as instruct)

December 2017 1HaskellADay problems and solutions

• December 29th, 2017: In Friday's #haskell problem we leave 2017 with a filter and a BANG! ... BANG! Today's #haskell solution we weave logging into the ETL article upload process. 
  
• December 28th, 2017: Thursday's #haskell problem is late AND a quicky: fetch a row of JSON from the database and pretty-print it. Thursday's #haskell solution had me leap from the bath tub and shout EUREKA! as I saw the issue in the JSON. 
• December 27th, 2017: In Wednesday's #haskell problem we learn that when you parse dates for your articles, you don't need to carbon-date it anymore. In the solution to yesterday's #haskell problem, we encounter and report some parsing issues around optionality. 
• December 26th, 2017: Tuesday's #haskell problem: scan an article archive, store an article archive; databases are neat that way. Today's #haskell solution: storing articles-as-JSON into a PostgreSQL database? No problem! 
• December 22nd, 2017: Friday's #haskell exercise we do our first bit of parsing with the help of tagsoup. Okay, this #haskell Aeson / TagSoup stuff is awesome for parsing JSON / HTML stuff. 
• December 20th, 2017: Wednesday's #haskell exercise. We take a large-ish JSON article archive, scan it, and spit out* a smaller-...ish JSON article archive. *'spit out' is a technical term. Today's #haskell solution provides a subset of the JSON article archive printed prettily.
• December 18th, 2017: Monday's #haskell problem: Friday you submitted an oembed request for goats, today you create a JSON oembed response service. Today's #haskell solution brings you a goat oembed service, serve with PHP. 
  
• December 15th, 2017: Today we build a goat oembed request. I kid you not! geddit? GEDDIT? Today's #haskell solution: OEmbed Goats requests, want? OEmbed Goats requests, GOT!  

• December 14th, 2017: Thursday's #haskell problem we sing 🎵 ... EVERYBODY'S WORKIN' FOR THE WEEKEND! 🎶 So, 18 composeable dates on the weekends. I'm freeing up my calendar, then! 
• December 13th, 2017: Wednesday's #haskell problem is a hot date! WOOT! Today's #haskell solution has 66 composable dates in 2017. Cool! 
• December 12th, 2017: Tuesday's #haskell problem is batching a SQL queryinstead of making multiple queries. It is so much faster! Today's #haskell solution has another LEFT JOIN in the SQL query to consolidate data gathering. 
• December 11th, 2017: Monday's #haskell problem is computing and storing exponential distribution values. The exponential distribution: today's #haskell solution shows it's really simple. 
  
• December 8th, 2017: For Friday's #haskell problem we parse NYT article summaries and upload them to a PostgreSQL database. Today's #haskell solution shows that our simple parsing exercise wasn't so simple. Isn't dirty data delightful? 
• December 7th, 2017: Throwing the switch with Thursday's #haskell with a hard reset of the database. For today's #haskell solution we do a hard reset: we wipe the recommendation and publish tables and repopulate. 
• December 6th, 2017: It's 'kinda' bad to return articles from a search that are already recommended. Wednesday's #haskell problem fixes this. Today's #haskell solution shows what a simple filter notMember can do. 
• December 5th, 2017: Tuesday's #haskell problem we narrow our focus and structure our keyword search-space only on keys requested in the NYT archive on PostgreSQL. With a little bit of monadic/applicative magic, we have narrowed keyword searches. 
• December 4th, 2017: For Monday's #haskell problem: "But can Haskell do anything useful?" Two words: ... yes.
• December 1st, 2017: For Friday's #haskell problem, what happens when the boss says: "That's good, but ..."? REWORK! THAT's what happens! Today's #haskell solution renders the source article in full and the recommended articles in brief. Got it!