Safe Haskell	Safe-Inferred
Language	Haskell2010

Torch.Data.CsvDatastream

Contents

Reexports

Synopsis

type BufferSize = Int
data NamedColumns
- = Unnamed
- | Named
data CsvDatastream' batches (named :: NamedColumns) = CsvDatastream' {
- filePath :: FilePath
- delimiter :: !Word8
- hasHeader :: HasHeader
- batchSize :: Int
- bufferedShuffle :: Maybe BufferSize
- dropLast :: Bool
}
type CsvDatastream batches = CsvDatastream' batches Unnamed
type CsvDatastreamNamed batches = CsvDatastream' batches Named
csvDatastream :: forall (isNamed :: NamedColumns) batches. FilePath -> CsvDatastream' batches isNamed
tsvDatastream :: forall (isNamed :: NamedColumns) batches. FilePath -> CsvDatastream' batches isNamed
class FromField a where
- parseField :: Field -> Parser a
class FromRecord a where
- parseRecord :: Record -> Parser a
class FromNamedRecord a where
- parseNamedRecord :: NamedRecord -> Parser a

Documentation

type BufferSize = Int Source #

data NamedColumns Source #

Constructors

Unnamed
Named

data CsvDatastream' batches (named :: NamedColumns) Source #

A CSV datastream. The datastream instance of this type streams samples of batches from a CSV file at the specified file path. Batches are yielded in constant memory, but if shuffling is enabled, then there will be at most BufferSize records stored in memory.

Constructors

CsvDatastream'
Fields filePath :: FilePath CSV file path. delimiter :: !Word8 Column delimiter. hasHeader :: HasHeader Does the file have a header? batchSize :: Int Batch size. , filter :: Maybe (batches -> Bool) bufferedShuffle :: Maybe BufferSize Buffered shuffle with specified buffer size. dropLast :: Bool Drop the last batch if it is less than batch size.

Instances

Instances details

(MonadBaseControl IO m, MonadSafe m, FromRecord batch) => Datastream m () (CsvDatastream batch) (Vector batch) Source #
Instance details Defined in Torch.Data.CsvDatastream Methods streamSamples :: CsvDatastream batch -> () -> ListT m (Vector batch) Source #
(MonadBaseControl IO m, MonadSafe m, FromNamedRecord batch) => Datastream m () (CsvDatastreamNamed batch) (Vector batch) Source #
Instance details Defined in Torch.Data.CsvDatastream Methods streamSamples :: CsvDatastreamNamed batch -> () -> ListT m (Vector batch) Source #

type CsvDatastream batches = CsvDatastream' batches Unnamed Source #

A specialized version of CsvDatastream'. Use this type if you want to decode a CSV file with records defined by the order of the columns.

type CsvDatastreamNamed batches = CsvDatastream' batches Named Source #

A specialized version of CsvDatastream'. Use this type if you want to decode a CSV file with records that have FromNamedRecord instance. This decodes each field of the record by the corresponding column with the given header name.

csvDatastream :: forall (isNamed :: NamedColumns) batches. FilePath -> CsvDatastream' batches isNamed Source #

Produce a CsvDatastream' from the given file with default options, and comma separated columns.

tsvDatastream :: forall (isNamed :: NamedColumns) batches. FilePath -> CsvDatastream' batches isNamed Source #

Produce a CsvDatastream' from the given file with default options, and tab separated columns.

Reexports

class FromField a where #

A type that can be converted from a single CSV field, with the possibility of failure.

When writing an instance, use empty, mzero, or fail to make a conversion fail, e.g. if a Field can't be converted to the given type.

Example type and instance:

{-# LANGUAGE OverloadedStrings #-}

data Color = Red | Green | Blue

instance FromField Color where
    parseField s
        | s == "R"  = pure Red
        | s == "G"  = pure Green
        | s == "B"  = pure Blue
        | otherwise = mzero

Methods

parseField :: Field -> Parser a #

Instances

Instances details

FromField Int16	Accepts a signed decimal number. Ignores whitespace.
Instance details Defined in Data.Csv.Conversion Methods parseField :: Field -> Parser Int16 #
FromField Int32	Accepts a signed decimal number. Ignores whitespace.
Instance details Defined in Data.Csv.Conversion Methods parseField :: Field -> Parser Int32 #
FromField Int64	Accepts a signed decimal number. Ignores whitespace.
Instance details Defined in Data.Csv.Conversion Methods parseField :: Field -> Parser Int64 #
FromField Int8	Accepts a signed decimal number. Ignores whitespace.
Instance details Defined in Data.Csv.Conversion Methods parseField :: Field -> Parser Int8 #
FromField Word16	Accepts an unsigned decimal number. Ignores whitespace.
Instance details Defined in Data.Csv.Conversion Methods parseField :: Field -> Parser Word16 #
FromField Word32	Accepts an unsigned decimal number. Ignores whitespace.
Instance details Defined in Data.Csv.Conversion Methods parseField :: Field -> Parser Word32 #
FromField Word64	Accepts an unsigned decimal number. Ignores whitespace.
Instance details Defined in Data.Csv.Conversion Methods parseField :: Field -> Parser Word64 #
FromField Word8	Accepts an unsigned decimal number. Ignores whitespace.
Instance details Defined in Data.Csv.Conversion Methods parseField :: Field -> Parser Word8 #
FromField ByteString
Instance details Defined in Data.Csv.Conversion Methods parseField :: Field -> Parser ByteString #
FromField ByteString
Instance details Defined in Data.Csv.Conversion Methods parseField :: Field -> Parser ByteString #
FromField ShortByteString
Instance details Defined in Data.Csv.Conversion Methods parseField :: Field -> Parser ShortByteString #
FromField Scientific	Accepts the same syntax as `rational`. Ignores whitespace. Since: cassava-0.5.1.0
Instance details Defined in Data.Csv.Conversion Methods parseField :: Field -> Parser Scientific #
FromField Text	Assumes UTF-8 encoding. Fails on invalid byte sequences.
Instance details Defined in Data.Csv.Conversion Methods parseField :: Field -> Parser Text #
FromField Text	Assumes UTF-8 encoding. Fails on invalid byte sequences.
Instance details Defined in Data.Csv.Conversion Methods parseField :: Field -> Parser Text #
FromField ShortText	Assumes UTF-8 encoding. Fails on invalid byte sequences. Since: cassava-0.5.0.0
Instance details Defined in Data.Csv.Conversion Methods parseField :: Field -> Parser ShortText #
FromField Integer	Accepts a signed decimal number. Ignores whitespace.
Instance details Defined in Data.Csv.Conversion Methods parseField :: Field -> Parser Integer #
FromField Natural	Accepts an unsigned decimal number. Ignores whitespace. Since: cassava-0.5.1.0
Instance details Defined in Data.Csv.Conversion Methods parseField :: Field -> Parser Natural #
FromField ()	Ignores the `Field`. Always succeeds.
Instance details Defined in Data.Csv.Conversion Methods parseField :: Field -> Parser () #
FromField Char	Assumes UTF-8 encoding.
Instance details Defined in Data.Csv.Conversion Methods parseField :: Field -> Parser Char #
FromField Double	Accepts same syntax as `rational`. Ignores whitespace.
Instance details Defined in Data.Csv.Conversion Methods parseField :: Field -> Parser Double #
FromField Float	Accepts same syntax as `rational`. Ignores whitespace.
Instance details Defined in Data.Csv.Conversion Methods parseField :: Field -> Parser Float #
FromField Int	Accepts a signed decimal number. Ignores whitespace.
Instance details Defined in Data.Csv.Conversion Methods parseField :: Field -> Parser Int #
FromField Word	Accepts an unsigned decimal number. Ignores whitespace.
Instance details Defined in Data.Csv.Conversion Methods parseField :: Field -> Parser Word #
FromField a => FromField (Identity a)	Since: cassava-0.5.2.0
Instance details Defined in Data.Csv.Conversion Methods parseField :: Field -> Parser (Identity a) #
FromField a => FromField (Maybe a)	`Nothing` if the `Field` is `empty`, `Just` otherwise.
Instance details Defined in Data.Csv.Conversion Methods parseField :: Field -> Parser (Maybe a) #
FromField [Char]	Assumes UTF-8 encoding. Fails on invalid byte sequences.
Instance details Defined in Data.Csv.Conversion Methods parseField :: Field -> Parser [Char] #
FromField a => FromField (Either Field a)	`Left field` if conversion failed, `Right` otherwise.
Instance details Defined in Data.Csv.Conversion Methods parseField :: Field -> Parser (Either Field a) #
FromField a => FromField (Const a b)	Since: cassava-0.5.2.0
Instance details Defined in Data.Csv.Conversion Methods parseField :: Field -> Parser (Const a b) #

class FromRecord a where #

A type that can be converted from a single CSV record, with the possibility of failure.

When writing an instance, use empty, mzero, or fail to make a conversion fail, e.g. if a Record has the wrong number of columns.

Given this example data:

John,56
Jane,55

here's an example type and instance:

data Person = Person { name :: !Text, age :: !Int }

instance FromRecord Person where
    parseRecord v
        | length v == 2 = Person <$>
                          v .! 0 <*>
                          v .! 1
        | otherwise     = mzero

Minimal complete definition

Nothing

Methods

parseRecord :: Record -> Parser a #

Instances

Instances details

FromField a => FromRecord (Only a)
Instance details Defined in Data.Csv.Conversion Methods parseRecord :: Record -> Parser (Only a) #
FromField a => FromRecord (Vector a)
Instance details Defined in Data.Csv.Conversion Methods parseRecord :: Record -> Parser (Vector a) #
(FromField a, Unbox a) => FromRecord (Vector a)
Instance details Defined in Data.Csv.Conversion Methods parseRecord :: Record -> Parser (Vector a) #
FromField a => FromRecord [a]
Instance details Defined in Data.Csv.Conversion Methods parseRecord :: Record -> Parser [a] #
(FromField a, FromField b) => FromRecord (a, b)
Instance details Defined in Data.Csv.Conversion Methods parseRecord :: Record -> Parser (a, b) #
(FromField a, FromField b, FromField c) => FromRecord (a, b, c)
Instance details Defined in Data.Csv.Conversion Methods parseRecord :: Record -> Parser (a, b, c) #
(FromField a, FromField b, FromField c, FromField d) => FromRecord (a, b, c, d)
Instance details Defined in Data.Csv.Conversion Methods parseRecord :: Record -> Parser (a, b, c, d) #
(FromField a, FromField b, FromField c, FromField d, FromField e) => FromRecord (a, b, c, d, e)
Instance details Defined in Data.Csv.Conversion Methods parseRecord :: Record -> Parser (a, b, c, d, e) #
(FromField a, FromField b, FromField c, FromField d, FromField e, FromField f) => FromRecord (a, b, c, d, e, f)
Instance details Defined in Data.Csv.Conversion Methods parseRecord :: Record -> Parser (a, b, c, d, e, f) #
(FromField a, FromField b, FromField c, FromField d, FromField e, FromField f, FromField g) => FromRecord (a, b, c, d, e, f, g)
Instance details Defined in Data.Csv.Conversion Methods parseRecord :: Record -> Parser (a, b, c, d, e, f, g) #
(FromField a, FromField b, FromField c, FromField d, FromField e, FromField f, FromField g, FromField h) => FromRecord (a, b, c, d, e, f, g, h)
Instance details Defined in Data.Csv.Conversion Methods parseRecord :: Record -> Parser (a, b, c, d, e, f, g, h) #
(FromField a, FromField b, FromField c, FromField d, FromField e, FromField f, FromField g, FromField h, FromField i) => FromRecord (a, b, c, d, e, f, g, h, i)
Instance details Defined in Data.Csv.Conversion Methods parseRecord :: Record -> Parser (a, b, c, d, e, f, g, h, i) #
(FromField a, FromField b, FromField c, FromField d, FromField e, FromField f, FromField g, FromField h, FromField i, FromField j) => FromRecord (a, b, c, d, e, f, g, h, i, j)
Instance details Defined in Data.Csv.Conversion Methods parseRecord :: Record -> Parser (a, b, c, d, e, f, g, h, i, j) #
(FromField a, FromField b, FromField c, FromField d, FromField e, FromField f, FromField g, FromField h, FromField i, FromField j, FromField k) => FromRecord (a, b, c, d, e, f, g, h, i, j, k)
Instance details Defined in Data.Csv.Conversion Methods parseRecord :: Record -> Parser (a, b, c, d, e, f, g, h, i, j, k) #
(FromField a, FromField b, FromField c, FromField d, FromField e, FromField f, FromField g, FromField h, FromField i, FromField j, FromField k, FromField l) => FromRecord (a, b, c, d, e, f, g, h, i, j, k, l)
Instance details Defined in Data.Csv.Conversion Methods parseRecord :: Record -> Parser (a, b, c, d, e, f, g, h, i, j, k, l) #
(FromField a, FromField b, FromField c, FromField d, FromField e, FromField f, FromField g, FromField h, FromField i, FromField j, FromField k, FromField l, FromField m) => FromRecord (a, b, c, d, e, f, g, h, i, j, k, l, m)
Instance details Defined in Data.Csv.Conversion Methods parseRecord :: Record -> Parser (a, b, c, d, e, f, g, h, i, j, k, l, m) #
(FromField a, FromField b, FromField c, FromField d, FromField e, FromField f, FromField g, FromField h, FromField i, FromField j, FromField k, FromField l, FromField m, FromField n) => FromRecord (a, b, c, d, e, f, g, h, i, j, k, l, m, n)
Instance details Defined in Data.Csv.Conversion Methods parseRecord :: Record -> Parser (a, b, c, d, e, f, g, h, i, j, k, l, m, n) #
(FromField a, FromField b, FromField c, FromField d, FromField e, FromField f, FromField g, FromField h, FromField i, FromField j, FromField k, FromField l, FromField m, FromField n, FromField o) => FromRecord (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o)
Instance details Defined in Data.Csv.Conversion Methods parseRecord :: Record -> Parser (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o) #

class FromNamedRecord a where #

A type that can be converted from a single CSV record, with the possibility of failure.

When writing an instance, use empty, mzero, or fail to make a conversion fail, e.g. if a Record has the wrong number of columns.

Given this example data:

name,age
John,56
Jane,55

here's an example type and instance:

{-# LANGUAGE OverloadedStrings #-}

data Person = Person { name :: !Text, age :: !Int }

instance FromNamedRecord Person where
    parseNamedRecord m = Person <$>
                         m .: "name" <*>
                         m .: "age"

Note the use of the OverloadedStrings language extension which enables ByteString values to be written as string literals.

Minimal complete definition

Nothing

Methods

parseNamedRecord :: NamedRecord -> Parser a #

Instances

Instances details

(FromField a, FromField b, Ord a) => FromNamedRecord (Map a b)
Instance details Defined in Data.Csv.Conversion Methods parseNamedRecord :: NamedRecord -> Parser (Map a b) #
(Eq a, FromField a, FromField b, Hashable a) => FromNamedRecord (HashMap a b)
Instance details Defined in Data.Csv.Conversion Methods parseNamedRecord :: NamedRecord -> Parser (HashMap a b) #