import csv
import random
import math

def loadCsv(filename):
    lines = csv.reader(open(filename, "r"))
    dataset = list(lines)
    for i in range(len(dataset)):
        dataset[i] = [float(x) for x in dataset[i]]
    return dataset

def split(dataset, ratio):
    trainSize = int(len(dataset)*ratio)
    trainSet = []
    copy = list(dataset)
    while len(trainSet)<trainSize:
        index = random.randrange(len(copy))
        trainSet.append(copy.pop(index))
    return trainSet, copy

def separate(dataset):
    separated = {}
    for i in range(len(dataset)):
        vector = dataset[i]
        if vector[-1] not in separated:
            separated[vector[-1]] = []
        separated[vector[-1]].append(vector)
    return separated

def mean(numbers):
    return sum(numbers)/float(len(numbers))