Safe Haskell	None
Language	Haskell2010

DataFrame.Internal.Schema

Synopsis

data SchemaType where
- SType :: forall a. Columnable a => Proxy a -> SchemaType
schemaType :: Columnable a => SchemaType
newtype Schema = Schema {
- elements :: Map Text SchemaType
}

Documentation

data SchemaType where Source #

A runtime tag for a column’s element type.

Constructors

SType :: forall a. Columnable a => Proxy a -> SchemaType

Constructor carrying a Proxy of the element type.

Instances

Instances details

Show SchemaType Source #	Show the underlying element type using `typeRep`. Examples Expand `>>>` `:set -XTypeApplications``>>>` `show (schemaType @Bool)`"Bool"
Instance details Defined in DataFrame.Internal.Schema Methods showsPrec :: Int -> SchemaType -> ShowS # show :: SchemaType -> String # showList :: [SchemaType] -> ShowS #
Eq SchemaType Source #	Two `SchemaType`s are equal iff their element types are the same. Examples Expand `>>>` `:set -XTypeApplications``>>>` `schemaType @Int == schemaType @Int`True `>>>` `schemaType @Int == schemaType @Integer`False
Instance details Defined in DataFrame.Internal.Schema Methods (==) :: SchemaType -> SchemaType -> Bool # (/=) :: SchemaType -> SchemaType -> Bool #

schemaType :: Columnable a => SchemaType Source #

Construct a SchemaType for the given a.

Examples

Expand

>>> :set -XTypeApplications
>>> schemaType @T.Text == schemaType @T.Text
True

>>> show (schemaType @Double)
"Double"

newtype Schema Source #

Logical schema of a DataFrame: a mapping from column names to their element types (SchemaType).

Examples

Expand

Constructing and querying a schema:

>>> import qualified Data.Map as M
>>> import qualified Data.Text as T
>>> let s = Schema (M.fromList [("country", schemaType @T.Text), ("amount", schemaType @Double)])
>>> M.lookup "amount" (elements s) == Just (schemaType @Double)
True

Extending a schema:

>>> let s' = Schema (M.insert "discount" (schemaType @Double) (elements s))
>>> M.member "discount" (elements s')
True

Equality is structural over the map contents:

>>> let a = Schema (M.fromList [("x", schemaType @Int), ("y", schemaType @Double)])
>>> let b = Schema (M.fromList [("y", schemaType @Double), ("x", schemaType @Int)])
>>> a == b
True

Constructors

Schema
Fields elements :: Map Text SchemaType Mapping from column name to its `SchemaType`. Invariant: keys are unique column names. A missing key means the column is not present in the schema.

Instances

Instances details

Show Schema Source #
Instance details Defined in DataFrame.Internal.Schema Methods showsPrec :: Int -> Schema -> ShowS # show :: Schema -> String # showList :: [Schema] -> ShowS #
Eq Schema Source #
Instance details Defined in DataFrame.Internal.Schema Methods (==) :: Schema -> Schema -> Bool # (/=) :: Schema -> Schema -> Bool #