# The goal here is to create a double histogram with string labels which is not supported yet with the hist() matplotlib function

import matplotlib.pyplot as plt
import numpy as np
from collections import Counter

# Dead list
l1 = titanic[titanic["Survived"] == 0]["Embarked"].dropna()
# Survivor list
l2 = titanic[titanic["Survived"] == 1]["Embarked"].dropna()

# draw histogram function
def hist2Str(_l1_Values, _l2_Values, _l1_Label, _l2_Label, _X_Label, _Y_Label):
    step = 0.3
    # Values lists 1 & 2
    count1 = Counter(_l1_Values)
    counts1 = count1.values()
    count2 = Counter(_l2_Values)
    counts2 = count2.values()
    # Labels in x
    labels = count1.keys()

    # Draw histogram
    bar_x = np.arange(len(counts1))
    plt.bar(bar_x, counts1, step, align = 'center')
    plt.bar(bar_x + step, counts2, step, color='r', align = 'center')
    plt.xticks(bar_x + step/2, labels)
    # Axis labels & draw
    plt.ylabel(_Y_Label)
    plt.xlabel(_X_Label)
    plt.legend([_l1_Label, _l2_Label])
    plt.draw()
hist2Str(l1, l2, "Dead", "Survived", "Embarked", "Passenger")