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Changed directory: /home/trifon/fmisync/Courses/2021_22/FP_2021_22/sandbox/lectures/haskell/
λ> :t []
[] :: [a]
λ> :t ""
"" :: [Char]
λ> "" == []
True
λ> 2:[]
[2]
λ> head [1,2,3]
1
λ> head []
*** Exception: Prelude.head: empty list
λ> tail [1,2,3]
[2,3]
λ> tail []
*** Exception: Prelude.tail: empty list
λ> tail [1,2,3]
[2,3]
λ> head [1,2,3]
1
λ> null [1,2,3]
False
λ> null []
True
λ> length [1,2,3]
3
λ> length []
0
λ> length [1,2,3]
3
λ> length []
0
λ> [1..10]
[1,2,3,4,5,6,7,8,9,10]
λ> ['a'..'e']
"abcde"
λ> [1.23..4.56]
[1.23,2.23,3.23,4.23]
λ> enumFromTo 1.23 4.56
[1.23,2.23,3.23,4.23]
λ> enumFromTo 1 10
[1,2,3,4,5,6,7,8,9,10]
λ> succ 'a'
'b'
λ> succ 1.23
2.23
λ> enumFromTo 'a' 'e'
"abcde"
λ> enumFromTo 1.23 4.56
[1.23,2.23,3.23,4.23]
λ> :t enumFromTo
enumFromTo :: (Ord a, Enum a) => a -> a -> [a]
λ> :t enumFromTo
enumFromTo :: (Ord a, Num a) => a -> a -> [a]
λ> :t enumFromTo
enumFromTo :: (Ord a, Enum a) => a -> a -> [a]
λ> :t enumFromThenTo
enumFromThenTo :: (Ord a, Num a) => a -> a -> a -> [a]
λ> [1,4..15]
[1,4,7,10,13]
λ> enumFromThenTo 1 4 15
[1,4,7,10,13]
λ> ['a','e'..'z']
"aeimquy"
λ> [1..5] ++ [10..20]
[1,2,3,4,5,10,11,12,13,14,15,16,17,18,19,20]
λ> [1..5] ++ [10..20]
[1,2,3,4,5,10,11,12,13,14,15,16,17,18,19,20]
λ> [1..5] ++ []
[1,2,3,4,5]
λ> :t (++)
(++) :: [a] -> [a] -> [a]
λ> reverse [1..5]
[5,4,3,2,1]
λ> :t reverse
reverse :: [[a]] -> [a]
λ> reverse [[1,2,3],[4,5,6],[7,8,9]]
[7,8,9,4,5,6,1,2,3]
λ> reverse [1..5]
[5,4,3,2,1]
λ> reverse [[1,2,3],[4,5,6],[7,8,9]]
[[7,8,9],[4,5,6],[1,2,3]]
λ> "Haskell" !! 2
's'
λ> "Haskell" !! 2
's'
λ> [1..10] !! 6
7
λ> [1..10] !! (-1)
*** Exception: Невалиден индекс!
CallStack (from HasCallStack):
  error, called at /home/trifon/fmisync/Courses/2021_22/FP_2021_22/sandbox/lectures/haskell/Lists.hs:43:14 in main:Lists
λ> elem 3 [1..5]
True
λ> elem 10 [1..5]
False
λ> :t elem
elem :: (Foldable t, Eq a) => a -> t a -> Bool
λ> elem 10 [1..5]
False
λ> elem 3 [1..5]
True
λ> 3 `elem` [1..5]
True
λ> 3 ∈ [1..5]
True
λ> 10 ∈ [1..5]
False
λ> 10 `elem` [1..5]
False
λ> 10 `elem` [1..5]
False
λ> 3 `elem` [1..5]
True
λ> 3 `елемент_на` [1..5]
True
λ> :t elem
elem :: Eq a => a -> [a] -> Bool
λ> :t елемент_на
елемент_на :: Eq a => a -> [a] -> Bool
λ> :t (++[])
(++[]) :: [a] -> [a]
λ> :t reverse
reverse :: [a] -> [a]
λ> show 15
"15"
λ> show 1.23
"1.23"
λ> show (1,2)
"(1,2)"
λ> show [(1,2),(3,4)]
"[(1,2),(3,4)]"
λ> read "1"
*** Exception: Prelude.read: no parse
λ> (read "1")::Int
1
λ> (read "1")::Double
1.0
λ> (read "1")::String
"*** Exception: Prelude.read: no parse
λ> (read "1")::Char
*** Exception: Prelude.read: no parse
λ> (read "[1,2]")::[Int]
[1,2]
λ> (read "[(1,2),(3,4)]")::[(Int,Int)]
[(1,2),(3,4)]
λ> :t Prelude.length
Prelude.length :: Foldable t => t a -> Int
λ> :t Prelude.enumFromTo
Prelude.enumFromTo :: Enum a => a -> a -> [a]
λ> :t 2
2 :: Num p => p
λ> 2 == length [1,2]
True
λ> :t 2.3
2.3 :: Fractional p => p
λ> 2.3 == length [1,2]
False
λ> :t length [1,2]
length [1,2] :: Num p => p
λ> :t length [1,2]
length [1,2] :: Int
λ> False < True
True
λ> [(x,y) | x <- [1..5], y <- [6..10]]
[(1,6),(1,7),(1,8),(1,9),(1,10),(2,6),(2,7),(2,8),(2,9),(2,10),(3,6),(3,7),(3,8),(3,9),(3,10),(4,6),(4,7),(4,8),(4,9),(4,10),(5,6),(5,7),(5,8),(5,9),(5,10)]
λ> [x +y | x <- [1..5], y <- [6..10]]
[7,8,9,10,11,8,9,10,11,12,9,10,11,12,13,10,11,12,13,14,11,12,13,14,15]
λ> [x * y | x <- [1..5], y <- [6..10], x + y <= 14]
[6,7,8,9,10,12,14,16,18,20,18,21,24,27,30,24,28,32,36,40,30,35,40,45]
λ> pythagoreanTriples 1 10
[(3,4,5),(4,3,5),(6,8,10),(8,6,10)]
λ> pythagoreanTriples 1 10
[(3,4,5),(6,8,10)]
λ> pythagoreanTriples 1 10
[(3,4,5)]
λ> pythagoreanTriples 1 100
[(3,4,5),(5,12,13),(7,24,25),(8,15,17),(9,40,41),(11,60,61),(12,35,37),(13,84,85),(16,63,65),(20,21,29),(28,45,53),(33,56,65),(36,77,85),(39,80,89),(48,55,73),(65,72,97)]
λ> pythagoreanTriples 1 1000
[(3,4,5)Interrupted.
λ> pythagoreanTriples 1 1000
[(3,4,5),(5,12,13),(8,15,17),(7,24,25),(20,21,29),(12,35,37),(9,40,41),(28,45,53),(11,60,61),(16,63,65),(33,56,65),(48,55,73),(13,84,85),(36,77,85),(39,80,89),(65,72,97),(20,99,101),(60,91,109),(15,112,113),(44,117,125),(88,105,137),(17,144,145),(24,143,145),(51,140,149),(85,132,157),(119,120,169),(52,165,173),(19,180,181),(57,176,185),(104,153,185),(95,168,193),(28,195,197),(84,187,205),(133,156,205),(21,220,221),(140,171,221),(60,221,229),(105,208,233),(120,209,241),(32,255,257),(23,264,265),(96,247,265),(69,260,269),(115,252,277),(160,231,281),(161,240,289),(68,285,293),(136,273,305),(207,224,305),(25,312,313),(75,308,317),(36,323,325),(204,253,325)Interrupted.
λ> pythagoreanTriples 1 1000
[(3,4,5),(5,12,13),(8,15,17),(7,24,25),(20,21,29),(12,35,37),(9,40,41),(28,45,53),(11,60,61),(16,63,65),(33,56,65),(48,55,73),(13,84,85),(36,77,85),(39,80,89),(65,72,97),(20,99,101),(60,91,109),(15,112,113),(44,117,125),(88,105,137),(17,144,145),(24,143,145),(51,140,149),(85,132,157),(119,120,169),(52,165,173),(19,180,181),(57,176,185),(104,153,185),(95,168,193),(28,195,197),(84,187,205),(133,156,205),(21,220,221),(140,171,221)Interrupted.
λ> init [1..5]
[1,2,3,4]
λ> init [1..5]
[1,2,3,4]
λ> init []
*** Exception: /home/trifon/fmisync/Courses/2021_22/FP_2021_22/sandbox/lectures/haskell/Lists.hs:(75,1)-(76,21): Non-exhaustive patterns in function init

λ> last [1..5]
5
λ> last []
*** Exception: /home/trifon/fmisync/Courses/2021_22/FP_2021_22/sandbox/lectures/haskell/Lists.hs:(79,1)-(80,19): Non-exhaustive patterns in function last

λ> take 4 [1..10]
[1,2,3,4]
λ> take 4 [1..10]
[1,2,3,4]
λ> take 0 [1..10]
[]
λ> drop 4 [1..10]
[5,6,7,8,9,10]
λ> concat [[1,2,3],[4,5,6],[7,8,9]]
[1,2,3,4,5,6,7,8,9]
λ> f2 5
2
λ> f2 10
2
λ> f2 [1..4]
2
λ> :t f2
f2 :: b -> Integer
λ> map (+1) [1..5]
[2,3,4,5,6]
λ> map (+1) [1..5]
[2,3,4,5,6]
λ> map (+1) [1..5]
[2,3,4,5,6]
λ> filter (>3) [1..5]
[4,5]
λ> filter (>3) [1..5]
[4,5]
λ> filter (\f -> f 2 > 3) [(^2),(+1),(*3)]
filter (\f -> f 2 > 3) [(^2),(+1),(*3)]
  :: (Num a, Ord a) => [a -> a]
λ> [ (x,y) | x <- [1..3], y <- [4..6] ]
[(1,4),(1,5),(1,6),(2,4),(2,5),(2,6),(3,4),(3,5),(3,6)]
λ> map (\x -> x) [1..3]
[1,2,3]
λ> map (\x -> map (\y -> (x, y)) [4..6]) [1..3]
[[(1,4),(1,5),(1,6)],[(2,4),(2,5),(2,6)],[(3,4),(3,5),(3,6)]]
λ> concat (map (\x -> map (\y -> (x, y)) [4..6]) [1..3])
[(1,4),(1,5),(1,6),(2,4),(2,5),(2,6),(3,4),(3,5),(3,6)]
λ> concatMap (\x -> map (\y -> (x, y)) [4..6]) [1..3]
[(1,4),(1,5),(1,6),(2,4),(2,5),(2,6),(3,4),(3,5),(3,6)]
λ> concatMap (\z -> concatMap (\x -> map (\y -> (x, y)) [4..6]) [1..3]) [7..9]
[(1,4),(1,5),(1,6),(2,4),(2,5),(2,6),(3,4),(3,5),(3,6),(1,4),(1,5),(1,6),(2,4),(2,5),(2,6),(3,4),(3,5),(3,6),(1,4),(1,5),(1,6),(2,4),(2,5),(2,6),(3,4),(3,5),(3,6)]
λ> concatMap (\z -> concatMap (\x -> map (\y -> (x, y, z)) [4..6]) [1..3]) [7..9]
[(1,4,7),(1,5,7),(1,6,7),(2,4,7),(2,5,7),(2,6,7),(3,4,7),(3,5,7),(3,6,7),(1,4,8),(1,5,8),(1,6,8),(2,4,8),(2,5,8),(2,6,8),(3,4,8),(3,5,8),(3,6,8),(1,4,9),(1,5,9),(1,6,9),(2,4,9),(2,5,9),(2,6,9),(3,4,9),(3,5,9),(3,6,9)]
λ> take 10 (enumF 2)
[2,3,4,5,6,7,8,9,10,11]
λ>