matplotlib画图中tick_params与autofmt_xdate两个函数作用为何失效？

Question

问题出现在注释行（两行）中。

import matplotlib.pyplot as plt
import datetime
import matplotlib.dates as mdates
import numpy as np

fix, ax = plt.subplots()


months = mdates.MonthLocator()
dateFmt = mdates.DateFormatter('%m/%d/%y')

ax.xaxis.set_major_formatter(dateFmt)
ax.xaxis.set_minor_locator(months)

ax.tick_params(axis='both', direction='out', labelsize=15) # 上面和右边坐标轴刻度没出现？

date1 = datetime.date(2008, 4, 17)
date2 = datetime.date(2017, 5, 4)
delta = datetime.timedelta(days=5)
dates = mdates.drange(date1, date2, delta)

y = np.random.normal(100, 15, len(dates))

ax.plot_date(dates, y, 'b-', alpha=0.7)


# plt.tight_layout()
fig.autofmt_xdate() # x 坐标的lable没有自动旋转？

plt.show()

Answer 1

fix还是fig