Data.List

• no need for qualified imports

• intersperse

intersperse '.' "monkey"
> "m.o.n.k.e.y"

• intercalate
  • insert element between the list and flattens

intercalate " " ["hello", "there", "world"]
> "hello there world"

• transpose
  • convert collect to rows, and vice versa
• foldl', foldl1'
  • regular folds are lazy and will not calculate the intermediate accumulator value
  • instead it will make a promise and put it on the stack as a thunk and the stack can overflow
  • these stricter folds will calculate it right away
• concat
  • flattens the list of lists

concat [[1,2,3], [4,5,6], [7,8,9]]
> [1,2,3,4,5,6,7,8,9]

• concatMap
  • map function to list and concatenating results
• and
  • takes list of boolean values and returns True only if all elems are True

and $ map (>4) [5,6,7,8]
> True

• or
  • at least one True
• any, all
  • takes predicate and check if any or
  • same as mapping over list and doing and, or
• iterate
  • keeping applying function to value and the results into an infinite list

take 10 $ iterate (*2) 1

• splitAt
  • split list at # of elements and returns the two parts in two lists

splitAt 3 "heyman"
> ("hey", "man")

• takeWhile
• dropWhile
  • like takeWhile but drops the elements until predicate is False and return the rest of the list
• span
  • like takeWhile but returns the two halves in a tuple

• break

• sort
• group
• inits
• tails
• isInfixOf
• isPrefixOf
• isSuffixOf
• elem
• notElem
• partition
• find
• elemIndex
• elemIndices
• findIndex
• findIndices
• zip3, zip4, zipWith3, zipWith4
• lines
• unlines
• words
• unwords
• nub
• delete
• \\
• union
• intersect
• insert
• genericLength
• genericTake
• genericDrop
• genericSplitAt
• genericIndex
• genericReplicate
• nubBy
• deleteBy
• unionBy
• intersectBy
• groupBy
• sortBy
• insertBy
• maximumBy
• minimumBy

• Data.Char

isControl isSpace isLower isUpper isAlpha isAlphaNum isPrint isDigit isOctDigit isHexDigit isLetter isMark isNumber isPunctuation isSymbol isSeparator isAscii isLatin1 isAsciiUpper isAsciiLower ` toUpper toLower toTitle digitToInt intToDigit ord

Data.Map

fromList empty insert null size singleton lookup member map filter toList keys elems fromListWith insertWith

Data.Set

fromList intersection difference union