#!/usr/bin/env python
# coding: utf-8

# # USA Births Data
# 
# *By Jake VanderPlas. See http://github.com/jakevdp/data-CDCbirths/*
# 
# This dataset records birth rates in the USA by year. It was compiled from data on the [CDC website](http://www.cdc.gov/nchs/data_access/Vitalstatsonline.htm) and is aggregated so as to comply with their terms of use.
# 
# *(This was inspired by Andrew Gelman's recent [NYC R Meetup](https://www.youtube.com/watch?v=ObS1hkOxyPA&feature=youtu.be) talk. Some of his writeup on the topic can be seen [on his blog](http://andrewgelman.com/2012/06/12/simple-graph-win-the-example-of-birthday-frequencies/))*

# In[1]:


get_ipython().run_line_magic('matplotlib', 'inline')
import matplotlib as mpl
import matplotlib.pyplot as plt
import seaborn; seaborn.set()

import pandas as pd
import numpy as np


# In[2]:


births = pd.read_csv('births.csv')
births.head()


# In[3]:


# Some data is mis-reported; e.g. June 31st, etc.
# remove these outliers via robust sigma-clipping
quartiles = np.percentile(births['births'], [25, 50, 75])
mu = quartiles[1]
sig = 0.7413 * (quartiles[2] - quartiles[0])
births = births.query('(births > @mu - 5 * @sig) & (births < @mu + 5 * @sig)')

# set 'day' column to integer; it originally was a string due to nulls
births['day'] = births['day'].astype(int)


# In[4]:


# Choose a leap year to display births by date
dates = [pd.datetime(2012, month, day)
         for (month, day) in zip(births['month'], births['day'])]


# In[5]:


# Plot the results
fig, ax = plt.subplots(figsize=(8, 6))
births.groupby(dates)['births'].mean().plot(ax=ax)

# Label the plot
ax.text('2012-1-1', 3950, "New Year's Day")
ax.text('2012-7-4', 4250, "Independence Day", ha='center')
ax.text('2012-9-4', 4850, "Labor Day", ha='center')
ax.text('2012-10-31', 4600, "Halloween", ha='right')
ax.text('2012-11-25', 4450, "Thanksgiving", ha='center')
ax.text('2012-12-25', 3800, "Christmas", ha='right')
ax.set(title='USA births by day of year (1969-1988)',
       ylabel='average daily births',
       xlim=('2011-12-20','2013-1-10'),
       ylim=(3700, 5400));

# Format the x axis with centered month labels
ax.xaxis.set_major_locator(mpl.dates.MonthLocator())
ax.xaxis.set_minor_locator(mpl.dates.MonthLocator(bymonthday=15))
ax.xaxis.set_major_formatter(plt.NullFormatter())
ax.xaxis.set_minor_formatter(mpl.dates.DateFormatter('%h'));


# Apparently American women *really* love their holidays!