import csv
import re


#Read in data and store it in dictionary
elemen_data = { element.lower():weight for element,weight in csv.reader(open("chem.csv", "rb"))}
formul_data = { element.lower():weight for element,weight in csv.reader(open("form.csv", "rb"))}

while True:
    choice = int(raw_input("Element name or Formula? (1/2): "))

    if choice == 1:
        elements = {}
        numberOfPrompts = int(raw_input("Enter total amount of elements: "))
        for i in range(numberOfPrompts):
            # will prompt "Enter Element 1: " on the first iteration
            userInput = raw_input("Enter Element %s: " % (i+1, ))
            elements[userInput] = float(elemen_data.get(userInput.lower()))
        for element in elements.keys():
            weightSum = 0
            for weight in elements.values():
                weightSum += weight

        print "Total weight =" ,weightSum

    if choice == 2:
        print "Not ready, try a later version"
        formula = raw_input("Enter formula: ")


        [a for a in re.split(r'([A-Z][a-z]*)', 'MgSO4') if a]

        weight_sum = sum(float(formul_data.get(elem.lower())) for elem in elements)
        print "Total weight =", weightSum

    if choice == 0:
        break