Haskell Data Analysis Cookbook

Deduplication of nonconflicting data items

Duplication is a common problem when collecting large amounts of data. In this recipe, we will combine similar records in a way that ensures no information is lost.

Getting ready

Create an input.csv file with repeated data:

How to do it...

Create a new file, which we will call Main.hs, and perform the following steps:

1. We will be using the CSV, Map, and Maybe packages:

   import Text.CSV (parseCSV, Record)
   import Data.Map (fromListWith)
   import Control.Applicative ((<|>))

2. Define the Item data type corresponding to the CSV input:

   data Item = Item { name :: String , color :: Maybe String , cost :: Maybe Float } deriving ...