练习：绘制直方图

#coding:utf-8
#/usr/bin/python
import numpy as np
import matplotlib as mpl
import matplotlib.pyplot as plt


if __name__ == '__main__':
    mpl.rcParams['font.sans-serif'] = [u'SimHei']
    mpl.rcParams['axes.unicode_minus'] = False  # win正常显示中文设置    

    mu = 2
    sigma = 3
    data = mu + sigma * np.random.randn(1000)
    h = plt.hist(data, 30, normed=1, color='#FFFFA0')
    x = h[1]
    y = norm.pdf(x, loc=mu, scale=sigma) #概率密度函数
    plt.plot(x, y, 'r-', x, y, 'ro', linewidth=2, markersize=4)
    plt.grid()
    plt.show()