Visualizing points using Graphics.EasyPlot

Sometimes, it's convenient to simply visualize data points before clustering or classifying to inspect the data. This recipe will feed a list of points to a plotting library to easily see a diagram of the data.

Getting ready

Install easyplot from cabal:

$ cabal install easyplot

Create a CSV file containing two-dimensional points:

$ cat input.csv

1,2
2,3
3,1
4,5
5,3
6,1

How to do it…

In a new file, Main.hs, follow these steps:

1. Import the required library to read in CSV data as well the library to plot points:

   import Text.CSV
   import Graphics.EasyPlot

2. Create a helper function to convert a list of string records into a list of doubles. For example, we want to convert [ "1.0,2.0", "3.5,4.5" ] into [ (1.0, 2.0), (3.5, 4.5) ]:

   tupes :: [[String]] -> [(Double, Double)]
   
   tupes records = [ (read x, read y) | [x, y] <- records ]

3. In main, parse the CSV file to be used later on:

   main = do 
     result <- parseCSVFromFile "input...