import csv

import matplotlib.pyplot as plt


def csv_rows_to_label_count(rows, column):
    """
    take a list of csv rows and for a given column 
    return a dictionary of labels mapped to the number of times
    that label appears
    """
    results = {}
    # loop through rows 
    # if we are seeing the label for the first time set label to 1
    # otherwise increment that label's current count by 1
    for row in rows: 
        val = row[column]
	if val == "":
	    val = "Unknown"

        if results.has_key(val):
            results[val] = results[val] + 1
        else:
            results[val] = 1

    return results


with open("Whorls.csv") as f:
	reader = csv.DictReader(f)
	results = csv_rows_to_label_count(reader, 'Structure')

for key in results:
  print("%s:%s" % (key, results[key]))