MODULES

MODULES

1. set of functions, types, class types

2. Program

   • Set of modules

3. Generic module

   • use for a lot of programs

4. standard haskell library

   • prelude module
   • import modules
     • Import <module name>
     • Import modules using GHCI
       • :m + Data.List
       • :m + Data.List Data.Map Data.Set
       • import qualified Data.Map

5. DATA.LIST

   • intersperse '.' "MONKEY" => "M.O.N.K.E.Y"
   • transpose [[1,2,3],[4,5,6],[7,8,9]] [[1,4,7],[2,5,8],[3,6,9]]
   • concat [[3,4,5],[2,3,4],[2,1,1]] [3,4,5,2,3,4,2,1,1]
   • any (==4) [2,3,5,6,1,4] True
   • all (>4) [6,9,10] True
   • take 10 $ iterate (*2) 1 [1,2,4,8,16,32,64,128,256,512]
   • splitAt 3 "heyman" ("hey","man")
   • takeWhile (>3) [6,5,4,3,2,1,2,3,4,5,4,3,2,1] [6,5,4]
   • break (==4) [1,2,3,4,5,6,7] ([1,2,3],[4,5,6,7])
   • sort [8,5,3,2,1,6,4,2] [1,2,2,3,4,5,6,8]
   • group [1,1,1,1,2,2,2,2,3,3,2,2,2,5,6,7] [[1,1,1,1],[2,2,2,2],[3,3],[2,2,2],[5],[6],[7]]
   • "cat" `isInfixOf` "im a cat burglar" True
   • find (>4) [1,2,3,4,5,6] Just 5
     • The result that throws the function is Maybe
   • Nub: Clears repeated elements
   • more generic variants: they are called generic Length, generic Take, generic Drop, genericSplitAt, genericIndex and genericReplicate
     • use or return any number unlike its non-generic variants.
     • The nub, delete, union, intersect and group functions have their most general functions called nubBy, deleteBy, unionBy, intersectBy and groupBy.
     • The functions sort, insert, maximum and minimum also have their more general equivalents
       • sortBy, insertBy, maximumBy and minimumBy

6. DATA.CHAR

   • functions that deal with characters.
     • They return a Boolean each one of them.
   • isControl: check if a character is control or not.
   • isLower: check if a character is in lowercase.
   • isAlpha: check if a character is a letter.
   • isPrim: check if a character is printable. The control characters, for example, are not
   • isHexDigit: check if a character is a hexadecimal digit.
   • isSeparator: checks if a character is a Unicode space or separator.
   • isAsciiLower: checks if a character is lowercase and is also ascii.
   • toLower: converts a character to lowercase.
   • Coding function
     • encode :: Int -> String -> String encode shift msg = let ords = map ord msg shifted = map (+ shift) ords in map chr shifted

7. DATA.MAP

   • The association lists (also called dictionaries).
     • They are used to store keys and values
     • fromList
     • Empty
     • Insert
     • Singleton
     • Member
     • fromListWith: When using it in the following function it does not discard the duplicated keys, but it combines its values
   • map and filter work similarly to their list equivalents

8. DATA.SET

   • Set operations
     • sets like those of mathematics.
   • Mix between lists and dictionaries.
   • Mas eficientes que las listas.