Safe Haskell	None
Language	Haskell2010

DataFrame.Typed.Apply

Description

Typed column transformations: the apply/derive family and default-valued inserts, plus the horizontal merge (|||). Schema changes are tracked at the type level (e.g. applyColumn rewrites a column's element type via SetColumnType).

Synopsis

applyColumn :: forall (name :: Symbol) a b (cols :: [(Symbol, Type)]). (KnownSymbol name, a ~ SafeLookup name cols, Columnable a, Columnable b, AssertPresent name cols) => (a -> b) -> TypedDataFrame cols -> TypedDataFrame (SetColumnType name b cols)
applyMany :: forall (names :: [Symbol]) a (cols :: [(Symbol, Type)]). (AllKnownSymbol names, Columnable a, AssertAllColumnsHaveType names a cols) => (a -> a) -> TypedDataFrame cols -> TypedDataFrame cols
applyWhere :: forall (filterName :: Symbol) (targetName :: Symbol) a b (cols :: [(Symbol, Type)]). (KnownSymbol filterName, KnownSymbol targetName, a ~ SafeLookup filterName cols, b ~ SafeLookup targetName cols, Columnable a, Columnable b, AssertPresent filterName cols, AssertPresent targetName cols) => (a -> Bool) -> (b -> b) -> TypedDataFrame cols -> TypedDataFrame cols
applyAtIndex :: forall (name :: Symbol) a (cols :: [(Symbol, Type)]). (KnownSymbol name, a ~ SafeLookup name cols, Columnable a, AssertPresent name cols) => Int -> (a -> a) -> TypedDataFrame cols -> TypedDataFrame cols
safeApply :: forall (name :: Symbol) a b (cols :: [(Symbol, Type)]). (KnownSymbol name, a ~ SafeLookup name cols, Columnable a, Columnable b, AssertPresent name cols) => (a -> b) -> TypedDataFrame cols -> Either DataFrameException (TypedDataFrame (SetColumnType name b cols))
deriveWithExpr :: forall (name :: Symbol) a (cols :: [(Symbol, Type)]). (KnownSymbol name, Columnable a, AssertAbsent name cols) => TExpr cols a -> TypedDataFrame cols -> (TExpr (Snoc cols '(name, a)) a, TypedDataFrame (Snoc cols '(name, a)))
insertWithDefault :: forall (name :: Symbol) a (cols :: [(Symbol, Type)]) t. (KnownSymbol name, Columnable a, Foldable t, AssertAbsent name cols) => a -> t a -> TypedDataFrame cols -> TypedDataFrame ('(name, a) ': cols)
insertVectorWithDefault :: forall (name :: Symbol) a (cols :: [(Symbol, Type)]). (KnownSymbol name, Columnable a, AssertAbsent name cols) => a -> Vector a -> TypedDataFrame cols -> TypedDataFrame ('(name, a) ': cols)
insertUnboxedVector :: forall (name :: Symbol) a (cols :: [(Symbol, Type)]). (KnownSymbol name, Columnable a, Unbox a, AssertAbsent name cols) => Vector a -> TypedDataFrame cols -> TypedDataFrame ('(name, a) ': cols)
(|||) :: forall (left :: [(Symbol, Type)]) (right :: [(Symbol, Type)]). AssertDisjoint left right => TypedDataFrame left -> TypedDataFrame right -> TypedDataFrame (Append left right)

Documentation

applyColumn :: forall (name :: Symbol) a b (cols :: [(Symbol, Type)]). (KnownSymbol name, a ~ SafeLookup name cols, Columnable a, Columnable b, AssertPresent name cols) => (a -> b) -> TypedDataFrame cols -> TypedDataFrame (SetColumnType name b cols) Source #

Map a function over a column, rewriting its element type from a to b. The schema's entry for name is updated via SetColumnType.

df' = applyColumn @"age" (show :: Int -> String) df
-- the "age" column is now String-typed

applyMany :: forall (names :: [Symbol]) a (cols :: [(Symbol, Type)]). (AllKnownSymbol names, Columnable a, AssertAllColumnsHaveType names a cols) => (a -> a) -> TypedDataFrame cols -> TypedDataFrame cols Source #

Apply a type-preserving function to several columns at once. Every named column must already share the element type a (enforced by AssertAllColumnsHaveType).

applyWhere :: forall (filterName :: Symbol) (targetName :: Symbol) a b (cols :: [(Symbol, Type)]). (KnownSymbol filterName, KnownSymbol targetName, a ~ SafeLookup filterName cols, b ~ SafeLookup targetName cols, Columnable a, Columnable b, AssertPresent filterName cols, AssertPresent targetName cols) => (a -> Bool) -> (b -> b) -> TypedDataFrame cols -> TypedDataFrame cols Source #

Apply a function to a target column only on rows where a condition holds on a filter column. Both columns are named by type application; the target keeps its type.

applyWhere @"flagged" @"score" id (* 2) df

applyAtIndex :: forall (name :: Symbol) a (cols :: [(Symbol, Type)]). (KnownSymbol name, a ~ SafeLookup name cols, Columnable a, AssertPresent name cols) => Int -> (a -> a) -> TypedDataFrame cols -> TypedDataFrame cols Source #

Apply a type-preserving function to a single row of a column.

safeApply :: forall (name :: Symbol) a b (cols :: [(Symbol, Type)]). (KnownSymbol name, a ~ SafeLookup name cols, Columnable a, Columnable b, AssertPresent name cols) => (a -> b) -> TypedDataFrame cols -> Either DataFrameException (TypedDataFrame (SetColumnType name b cols)) Source #

Like applyColumn but returns the error instead of throwing.

deriveWithExpr :: forall (name :: Symbol) a (cols :: [(Symbol, Type)]). (KnownSymbol name, Columnable a, AssertAbsent name cols) => TExpr cols a -> TypedDataFrame cols -> (TExpr (Snoc cols '(name, a)) a, TypedDataFrame (Snoc cols '(name, a))) Source #

Derive a new column and also return a typed reference to it. The returned expression lives in the extended schema, so it can feed later operations.

insertWithDefault :: forall (name :: Symbol) a (cols :: [(Symbol, Type)]) t. (KnownSymbol name, Columnable a, Foldable t, AssertAbsent name cols) => a -> t a -> TypedDataFrame cols -> TypedDataFrame ('(name, a) ': cols) Source #

Insert a column from a Foldable, padding missing rows with a default.

insertVectorWithDefault :: forall (name :: Symbol) a (cols :: [(Symbol, Type)]). (KnownSymbol name, Columnable a, AssertAbsent name cols) => a -> Vector a -> TypedDataFrame cols -> TypedDataFrame ('(name, a) ': cols) Source #

Insert a boxed Vector, padding missing rows with a default.

insertUnboxedVector :: forall (name :: Symbol) a (cols :: [(Symbol, Type)]). (KnownSymbol name, Columnable a, Unbox a, AssertAbsent name cols) => Vector a -> TypedDataFrame cols -> TypedDataFrame ('(name, a) ': cols) Source #

Insert an unboxed Vector as a new column.

(|||) :: forall (left :: [(Symbol, Type)]) (right :: [(Symbol, Type)]). AssertDisjoint left right => TypedDataFrame left -> TypedDataFrame right -> TypedDataFrame (Append left right) Source #

Horizontal merge: place two DataFrames side by side. The schemas must be disjoint (no shared column names), enforced by AssertDisjoint; the result schema is their concatenation.