Haskell

General

Prelude

tuples

lists

strings

String in Haskell is a list of Chars: [Char]

functions

map
filter
foldl
foldr

Useful functions

Numerical functions

mod: modulo (reminder after numerical division)
div: integer division
even/odd: checks if a number is even/odd
lcm: lowest common multiplier
gcd: greatest common divisor

List functions

takeWhile condition list
length
head
last
tail
null
Data.List(nub): remove duplicates

String functions

show
read
Char.digitToInt

Operators

$!: strict (non-lazy) apply function operator