Modules

Modules

1. data.Map

   • Are list that are used to store key-value pairs where ordering doesn't matte
     • The way to represent association lists would be by having list of pairs
       • The Data.Map module offers association lists that are much faster
         • fromList
         • empty
         • insert
         • null
         • size
         • singleton
         • toList
         • lokup
         • meber
         • filter
         • fromListWith
         • insertWith

2. A Haskell module is a collection of related functions types and typeclass

   • The Haskell standard librery is split into modules each of them contains functions and types that are somehow related and serve some common purpose
   • A Haskell program is a collection of modules where the main module loads up the other modules and then uses the function defined ind them to do something
   • The syntax for importing modules in an Haskell script is import <module name>
     • If you just need a couple of functions from a module, you can selectively import just those functions

3. Data.Set

   • He most common operation when dealing with sets are interesting into a set, checking for membership and converting a set to a list
     • null,size, member, empty, singleton, insert, delet
     • union
     • difference
       • see which letters are in first set but aren't in the second one and vice versa
     • Insertion
       • see which elements they both share
     • fromList
       • It takes a list and converts it into a set
   • offers sets. Like sets from mathematics
     • They are a cross between lists and maps
       • All the elements in a set are unique. And because they're internally implemented with trees

4. Data.Char

   • It exports functions that deal with characters
     • Is helpful when filtering and mapping over strings because they're just list of characters
       • Expor functions over characters is true or false
         • isLetter
         • isMark
         • isNumber
         • isPuntuation
         • isSymbol
         • isSeparator
         • isAscii
         • isLatin
         • isAsciiUpper
         • isAsciiLower
         • isControl
         • isSpace
         • isLower
         • isUpper
         • isAlpha
         • isAlphaNum
         • isPrint
         • isDigit
         • isOctoDigit
         • isHexDigit

5. Data.List

   • It provides some very useful functions for dealing with them
   • Intersperse takes an element and a list and then puts that element in between each pair of elements in the list
   • Intercalate takes a list of lists and a list. It then inserts that list in between all those list and then flattens the result
   • Transpose transponses a list of lists. If you look at a list of list as a 2D matrix, the columns become the rows and vice versa
   • Concat flattens a list of lists into just a list of elements
   • vconcatMap is the same as first mapping a function to a list and then concatenating the list with concat