Modules

Modules

1. import Data.List

2. import Qualified Data.Map

3. A Haskell module is a collection of related functions, types and typeclasses. A Haskell program is a collection of modules where the main module loads up the other modules and then uses the functions defined in them to do something

4. Data.Char

   • does what its name suggests. It exports functions that deal with characters. It's also helpful when filtering and mapping over strings because they're just lists of characters.
   • Some functions
     • isControl
       • checks whether a character is a control character
     • isLower
       • checks whether a character is lower-cased
     • isUpper
       • checks whether a character is upper-cased
     • isNumber
       • checks whether a character is numeric

5. Data.List

   • Some functions
     • Intersperse
       • checks whether a character is numeric
     • Intercalate
       • takes a list of lists and a list. It then inserts that list in between all those lists and then flattens the result
     • Transpose
       • transposes a list of lists. If you look at a list of lists as a 2D matrix, the columns become the rows and vice versa

6. Data.Set

   • Some Functions
     • fromList
       • function works much like you would expect. It takes a list and converts it into a set
     • Difference
       • function to see which letters are in the first set but aren't in the second one and vice versa