haskell02.hs

haskell02.hs

ghci> [1,2,3]
[1,2,3]
ghci> ["foo","bar","string"]
["foo","bar","string"]
ghci> [True,False]
[True,False]

-- enumeration notation
ghci> [1..5]
[1,2,3,4,5]
ghci> [True, False, "testing"]

<interactive>:1:14:
    Couldn't match expected type `Bool' against inferred type `[Char]'
    In the expression: "testing"
    In the expression: [True, False, "testing"]
    In the definition of `it': it = [True, False, "testing"]
-- no way to turn the string into a Boolean

ghci> [1,2,3] ++ [4,5]
[1,2,3,4,5]
ghci> 1:[2,3]
[1,2,3]
ghci> [2,3]:4

<interactive>:1:6:
    No instance for (Num [[t]])
      arising from the literal `4' at <interactive>:1:6
    Possible fix: add an instance declaration for (Num [[t]])
    In the second argument of `(:)', namely `4'
    In the expression: [2, 3] : 4
    In the definition of `it': it = [2, 3] : 4


-- error message, because the first argument of (:) must be an element, and the second must be a list.

-- String
ghci> "This is String \n newline"
"This is String \n newline"
ghci> "This is String '\n' newline"
"This is String '\n' newline"
ghci> put
putChar   putStr    putStrLn
ghci> putStr "This is String \n newline"
This is String 
 newlineghci> 

ghci> let a = ['l', 'o', 't', 's', ' ', 'o', 'f', ' ', 'w', 'o', 'r', 'k']
ghci> a
"lots of work"
ghci> a == "lots of work"
True
ghci> ['b','c']
"bc"
ghci> 

ghci> "" == []
True
ghci> 'a':"bc" 
"abc"
ghci> 'a':['b','c']
"abc"
ghci> "bc":'a'

<interactive>:1:5:
    Couldn't match expected type `[[Char]]'
           against inferred type `Char'
    In the second argument of `(:)', namely 'a'
    In the expression: "bc" : 'a'
    In the definition of `it': it = "bc" : 'a'
ghci> "abc"++"abc"
"abcabc"
ghci> ['a','b','c']++['a','b','c']
"abcabc"