Copyright | (c) Laurent P. René de Cotret |
---|---|
License | MIT |
Maintainer | laurent.decotret@outlook.com |
Portability | portable |
Safe Haskell | Safe-Inferred |
Language | GHC2021 |
This module contains functions to serialize/deserialize generic Series
to/from bytes.
Use this module if you want to support all types of Series
. Otherwise,
you should use either the modules Data.Series.IO or Data.Series.Unboxed.IO.
Synopsis
- readCSV :: (Vector v a, Ord k, FromNamedRecord k, FromNamedRecord a) => ByteString -> Either String (Series v k a)
- readCSVFromFile :: (MonadIO m, Vector v a, Ord k, FromNamedRecord k, FromNamedRecord a) => FilePath -> m (Either String (Series v k a))
- writeCSV :: (Vector v a, ToNamedRecord k, ToNamedRecord a) => Series v k a -> ByteString
- writeCSVToFile :: (MonadIO m, Vector v a, ToNamedRecord k, ToNamedRecord a) => FilePath -> Series v k a -> m ()
Deserialize Series
readCSV :: (Vector v a, Ord k, FromNamedRecord k, FromNamedRecord a) => ByteString -> Either String (Series v k a) Source #
Read a comma-separated value (CSV) bytestream into a series.
Consider the following bytestream read from a file:
latitude,longitude,city 48.856667,2.352222,Paris 40.712778,-74.006111,New York City 25.0375,121.5625,Taipei -34.603333,-58.381667,Buenos Aires
We want to get a series of the latitude an longitude, indexed by the column "city". First, we need to do is to create a datatype representing the latitude and longitude information, and our index:
data LatLong = MkLatLong { latitude :: Double , longitude :: Double } deriving ( Show ) newtype City = MkCity String deriving ( Eq, Ord, Show )
Second, we need to create an instance of FromNamedRecord
for our new types:
import Data.Csv (FromNamedRecord
,(.:)
) instanceFromNamedRecord
LatLong whereparseNamedRecord
r = MkLatLong <$> r .: "latitude" <*> r .: "longitude" instanceFromNamedRecord
City whereparseNamedRecord
r = MkCity <$> r .: "city"
Finally, we're ready to read our stream:
import Data.Series.Generic import Data.Series.Generic.IO import Data.Vector main :: IO () main = do stream <- (...) -- Read the bytestring from somewhere let (latlongs ::Series
Vector City LatLong) = either (error . show) id <$>readCSV
stream print latlongs
readCSVFromFile :: (MonadIO m, Vector v a, Ord k, FromNamedRecord k, FromNamedRecord a) => FilePath -> m (Either String (Series v k a)) Source #
This is a helper function to read a CSV directly from a filepath.
See the documentation for readCSV
on how to prepare your types.
Then, for example, you can use readCSVFromFile
as:
import Data.Series.Generic import Data.Series.Generic.IO import Data.Vector main :: IO () main = do stream <- (...) -- Read the bytestring from somewhere let (latlongs ::Series
Vector City LatLong) = either (error . show) id <$>readCSV
stream print latlongs
Serialize Series
writeCSV :: (Vector v a, ToNamedRecord k, ToNamedRecord a) => Series v k a -> ByteString Source #
Read a comma-separated value (CSV) bytestream into a series.
Consider the following bytestream read from a file:
latitude,longitude,city 48.856667,2.352222,Paris 40.712778,-74.006111,New York City 25.0375,121.5625,Taipei -34.603333,-58.381667,Buenos Aires
We want to get a series of the latitude an longitude, indexed by the column "city". First, we need to do is to create a datatype representing the latitude and longitude information, and our index:
data LatLong = MkLatLong { latitude :: Double , longitude :: Double } deriving ( Show ) newtype City = MkCity String deriving ( Eq, Ord, Show )
Second, we need to create an instance of FromNamedRecord
for our new types:
import Data.Csv (FromNamedRecord
,(.:)
) instanceFromNamedRecord
LatLong whereparseNamedRecord
r = MkLatLong <$> r .: "latitude" <*> r .: "longitude" instanceFromNamedRecord
City whereparseNamedRecord
r = MkCity <$> r .: "city"
Finally, we're ready to read our stream:
import Data.Series import Data.Series.IO main :: IO () main = do stream <- (...) -- Read the bytestring from somewhere let (latlongs ::Series
City LatLong) = either (error . show) id <$>readCSV
stream print latlongs
writeCSVToFile :: (MonadIO m, Vector v a, ToNamedRecord k, ToNamedRecord a) => FilePath -> Series v k a -> m () Source #