Safe Haskell	None
Language	Haskell2010

DataFrame.Typed.Expr

Contents

Core typed expression type (re-exported from Types)
Column reference (schema-checked)
Literals
Conditional
Unary / binary lifting
Comparison operators
Logical operators
Aggregation combinators
Named expression helper
Sort helpers
Orphan instances

Description

Type-safe expression construction for typed DataFrames.

Unlike the untyped Expr a where column references are unchecked strings, TExpr ensures at compile time that:

Referenced columns exist in the schema
Column types match the expression type

Example

type Schema = '[Column "age" Int, Column "salary" Double]

-- This compiles:
goodExpr :: TExpr Schema Double
goodExpr = col @"salary"

-- This gives a compile-time error (column not found):
badExpr :: TExpr Schema Double
badExpr = col @"nonexistent"

-- This gives a compile-time error (type mismatch):
wrongType :: TExpr Schema Int
wrongType = col @"salary"  -- salary is Double, not Int

Synopsis

newtype TExpr (cols :: [Type]) a = TExpr {
- unTExpr :: Expr a
}
col :: forall (name :: Symbol) (cols :: [Type]) a. (KnownSymbol name, a ~ Lookup name cols, Columnable a, AssertPresent name cols) => TExpr cols a
lit :: forall a (cols :: [Type]). Columnable a => a -> TExpr cols a
ifThenElse :: forall a (cols :: [Type]). Columnable a => TExpr cols Bool -> TExpr cols a -> TExpr cols a -> TExpr cols a
lift :: forall a b (cols :: [Type]). (Columnable a, Columnable b) => (a -> b) -> TExpr cols a -> TExpr cols b
lift2 :: forall a b c (cols :: [Type]). (Columnable a, Columnable b, Columnable c) => (a -> b -> c) -> TExpr cols a -> TExpr cols b -> TExpr cols c
(.==.) :: forall a (cols :: [Type]). (Columnable a, Eq a) => TExpr cols a -> TExpr cols a -> TExpr cols Bool
(./=.) :: forall a (cols :: [Type]). (Columnable a, Eq a) => TExpr cols a -> TExpr cols a -> TExpr cols Bool
(.<.) :: forall a (cols :: [Type]). (Columnable a, Ord a) => TExpr cols a -> TExpr cols a -> TExpr cols Bool
(.<=.) :: forall a (cols :: [Type]). (Columnable a, Ord a) => TExpr cols a -> TExpr cols a -> TExpr cols Bool
(.>=.) :: forall a (cols :: [Type]). (Columnable a, Ord a) => TExpr cols a -> TExpr cols a -> TExpr cols Bool
(.>.) :: forall a (cols :: [Type]). (Columnable a, Ord a) => TExpr cols a -> TExpr cols a -> TExpr cols Bool
(.&&.) :: forall (cols :: [Type]). TExpr cols Bool -> TExpr cols Bool -> TExpr cols Bool
(.||.) :: forall (cols :: [Type]). TExpr cols Bool -> TExpr cols Bool -> TExpr cols Bool
not :: forall (cols :: [Type]). TExpr cols Bool -> TExpr cols Bool
sum :: forall a (cols :: [Type]). (Columnable a, Num a) => TExpr cols a -> TExpr cols a
mean :: forall a (cols :: [Type]). (Columnable a, Real a) => TExpr cols a -> TExpr cols Double
count :: forall a (cols :: [Type]). Columnable a => TExpr cols a -> TExpr cols Int
minimum :: forall a (cols :: [Type]). (Columnable a, Ord a) => TExpr cols a -> TExpr cols a
maximum :: forall a (cols :: [Type]). (Columnable a, Ord a) => TExpr cols a -> TExpr cols a
collect :: forall a (cols :: [Type]). Columnable a => TExpr cols a -> TExpr cols [a]
as :: forall a (cols :: [Type]). Columnable a => TExpr cols a -> Text -> NamedExpr
asc :: forall a (cols :: [Type]). Columnable a => TExpr cols a -> TSortOrder cols
desc :: forall a (cols :: [Type]). Columnable a => TExpr cols a -> TSortOrder cols

Core typed expression type (re-exported from Types)

newtype TExpr (cols :: [Type]) a Source #

A typed expression validated against schema cols, producing values of type a.

Unlike the untyped 'Expr a', a TExpr can only be constructed through type-safe combinators (col, lit, arithmetic operations) that verify column references exist in the schema with the correct type.

Use unTExpr to extract the underlying Expr for delegation to the untyped API.

Constructors

TExpr
Fields unTExpr :: Expr a

Instances

Instances details

(IsString a, Columnable a) => IsString (TExpr cols a) Source #
Instance details Defined in DataFrame.Typed.Expr Methods fromString :: String -> TExpr cols a #
(Floating a, Columnable a) => Floating (TExpr cols a) Source #
Instance details Defined in DataFrame.Typed.Expr Methods pi :: TExpr cols a # exp :: TExpr cols a -> TExpr cols a # log :: TExpr cols a -> TExpr cols a # sqrt :: TExpr cols a -> TExpr cols a # (**) :: TExpr cols a -> TExpr cols a -> TExpr cols a # logBase :: TExpr cols a -> TExpr cols a -> TExpr cols a # sin :: TExpr cols a -> TExpr cols a # cos :: TExpr cols a -> TExpr cols a # tan :: TExpr cols a -> TExpr cols a # asin :: TExpr cols a -> TExpr cols a # acos :: TExpr cols a -> TExpr cols a # atan :: TExpr cols a -> TExpr cols a # sinh :: TExpr cols a -> TExpr cols a # cosh :: TExpr cols a -> TExpr cols a # tanh :: TExpr cols a -> TExpr cols a # asinh :: TExpr cols a -> TExpr cols a # acosh :: TExpr cols a -> TExpr cols a # atanh :: TExpr cols a -> TExpr cols a # log1p :: TExpr cols a -> TExpr cols a # expm1 :: TExpr cols a -> TExpr cols a # log1pexp :: TExpr cols a -> TExpr cols a # log1mexp :: TExpr cols a -> TExpr cols a #
(Num a, Columnable a) => Num (TExpr cols a) Source #
Instance details Defined in DataFrame.Typed.Expr Methods (+) :: TExpr cols a -> TExpr cols a -> TExpr cols a # (-) :: TExpr cols a -> TExpr cols a -> TExpr cols a # (*) :: TExpr cols a -> TExpr cols a -> TExpr cols a # negate :: TExpr cols a -> TExpr cols a # abs :: TExpr cols a -> TExpr cols a # signum :: TExpr cols a -> TExpr cols a # fromInteger :: Integer -> TExpr cols a #
(Fractional a, Columnable a) => Fractional (TExpr cols a) Source #
Instance details Defined in DataFrame.Typed.Expr Methods (/) :: TExpr cols a -> TExpr cols a -> TExpr cols a # recip :: TExpr cols a -> TExpr cols a # fromRational :: Rational -> TExpr cols a #

Column reference (schema-checked)

col :: forall (name :: Symbol) (cols :: [Type]) a. (KnownSymbol name, a ~ Lookup name cols, Columnable a, AssertPresent name cols) => TExpr cols a Source #

Create a typed column reference. This is the key type-safety entry point.

The column name must exist in cols and its type must match a. Both checks happen at compile time via type families.

salary :: TExpr '[Column "salary" Double] Double
salary = col @"salary"

Literals

lit :: forall a (cols :: [Type]). Columnable a => a -> TExpr cols a Source #

Create a literal expression. Valid for any schema since it references no columns.

Conditional

ifThenElse :: forall a (cols :: [Type]). Columnable a => TExpr cols Bool -> TExpr cols a -> TExpr cols a -> TExpr cols a Source #

Conditional expression.

Unary / binary lifting

lift :: forall a b (cols :: [Type]). (Columnable a, Columnable b) => (a -> b) -> TExpr cols a -> TExpr cols b Source #

Lift a unary function into a typed expression.

lift2 :: forall a b c (cols :: [Type]). (Columnable a, Columnable b, Columnable c) => (a -> b -> c) -> TExpr cols a -> TExpr cols b -> TExpr cols c Source #

Lift a binary function into typed expressions.

Comparison operators

(.==.) :: forall a (cols :: [Type]). (Columnable a, Eq a) => TExpr cols a -> TExpr cols a -> TExpr cols Bool infixl 4 Source #

(./=.) :: forall a (cols :: [Type]). (Columnable a, Eq a) => TExpr cols a -> TExpr cols a -> TExpr cols Bool infixl 4 Source #

(.<.) :: forall a (cols :: [Type]). (Columnable a, Ord a) => TExpr cols a -> TExpr cols a -> TExpr cols Bool infixl 4 Source #

(.<=.) :: forall a (cols :: [Type]). (Columnable a, Ord a) => TExpr cols a -> TExpr cols a -> TExpr cols Bool infixl 4 Source #

(.>=.) :: forall a (cols :: [Type]). (Columnable a, Ord a) => TExpr cols a -> TExpr cols a -> TExpr cols Bool infixl 4 Source #

(.>.) :: forall a (cols :: [Type]). (Columnable a, Ord a) => TExpr cols a -> TExpr cols a -> TExpr cols Bool infixl 4 Source #

Logical operators

(.&&.) :: forall (cols :: [Type]). TExpr cols Bool -> TExpr cols Bool -> TExpr cols Bool infixr 3 Source #

(.||.) :: forall (cols :: [Type]). TExpr cols Bool -> TExpr cols Bool -> TExpr cols Bool infixr 2 Source #

not :: forall (cols :: [Type]). TExpr cols Bool -> TExpr cols Bool Source #

Aggregation combinators

sum :: forall a (cols :: [Type]). (Columnable a, Num a) => TExpr cols a -> TExpr cols a Source #

mean :: forall a (cols :: [Type]). (Columnable a, Real a) => TExpr cols a -> TExpr cols Double Source #

count :: forall a (cols :: [Type]). Columnable a => TExpr cols a -> TExpr cols Int Source #

minimum :: forall a (cols :: [Type]). (Columnable a, Ord a) => TExpr cols a -> TExpr cols a Source #

maximum :: forall a (cols :: [Type]). (Columnable a, Ord a) => TExpr cols a -> TExpr cols a Source #

collect :: forall a (cols :: [Type]). Columnable a => TExpr cols a -> TExpr cols [a] Source #

Named expression helper

as :: forall a (cols :: [Type]). Columnable a => TExpr cols a -> Text -> NamedExpr Source #

Create a NamedExpr for use with aggregateUntyped.

Sort helpers

asc :: forall a (cols :: [Type]). Columnable a => TExpr cols a -> TSortOrder cols Source #

Create an ascending sort order from a typed expression.

desc :: forall a (cols :: [Type]). Columnable a => TExpr cols a -> TSortOrder cols Source #

Create a descending sort order from a typed expression.

Orphan instances

(IsString a, Columnable a) => IsString (TExpr cols a) Source #
Instance details Methods fromString :: String -> TExpr cols a #
(Floating a, Columnable a) => Floating (TExpr cols a) Source #
Instance details Methods pi :: TExpr cols a # exp :: TExpr cols a -> TExpr cols a # log :: TExpr cols a -> TExpr cols a # sqrt :: TExpr cols a -> TExpr cols a # (**) :: TExpr cols a -> TExpr cols a -> TExpr cols a # logBase :: TExpr cols a -> TExpr cols a -> TExpr cols a # sin :: TExpr cols a -> TExpr cols a # cos :: TExpr cols a -> TExpr cols a # tan :: TExpr cols a -> TExpr cols a # asin :: TExpr cols a -> TExpr cols a # acos :: TExpr cols a -> TExpr cols a # atan :: TExpr cols a -> TExpr cols a # sinh :: TExpr cols a -> TExpr cols a # cosh :: TExpr cols a -> TExpr cols a # tanh :: TExpr cols a -> TExpr cols a # asinh :: TExpr cols a -> TExpr cols a # acosh :: TExpr cols a -> TExpr cols a # atanh :: TExpr cols a -> TExpr cols a # log1p :: TExpr cols a -> TExpr cols a # expm1 :: TExpr cols a -> TExpr cols a # log1pexp :: TExpr cols a -> TExpr cols a # log1mexp :: TExpr cols a -> TExpr cols a #
(Num a, Columnable a) => Num (TExpr cols a) Source #
Instance details Methods (+) :: TExpr cols a -> TExpr cols a -> TExpr cols a # (-) :: TExpr cols a -> TExpr cols a -> TExpr cols a # (*) :: TExpr cols a -> TExpr cols a -> TExpr cols a # negate :: TExpr cols a -> TExpr cols a # abs :: TExpr cols a -> TExpr cols a # signum :: TExpr cols a -> TExpr cols a # fromInteger :: Integer -> TExpr cols a #
(Fractional a, Columnable a) => Fractional (TExpr cols a) Source #
Instance details Methods (/) :: TExpr cols a -> TExpr cols a -> TExpr cols a # recip :: TExpr cols a -> TExpr cols a # fromRational :: Rational -> TExpr cols a #