如何在使用matplotlib的pyplot绘制的图形上设置x轴标签？

Question

I'm trying to plot sales and expenses values (on y-axis) over years (on x-axis) as given below. I'm expecting that the following code will set 2004, 2005, 2006 and 2007 as x-axis values. But, it is not showing as expected. See the image attached below. Let me know how to set the years values correctly on x-axis.

import matplotlib.pyplot as plt
years = [2004, 2005, 2006, 2007]
sales = [1000, 1170, 660, 1030]
expenses = [400, 460, 1120, 540]
plt.plot(years, sales)
plt.plot(years, expenses)
plt.show()

Answer 1

This would also do the work, in a different way:

fig=plt.figure()
ax = fig.add_subplot(111)

years = [2004, 2005, 2006, 2007]

sales = [1000, 1170, 660, 1030]


ax.plot(years, sales)
ax.xaxis.set_major_formatter(matplotlib.ticker.FormatStrFormatter('%d'))

plt.show()

Answer 2

The following piece of code should work for you

 import matplotlib.pyplot as plt
 import matplotlib.dates as mdates
 import datetime as dt

 years = [2004, 2005, 2006, 2007]

 sales = [1000, 1170, 660, 1030]

 expenses = [400, 460, 1120, 540]


 x = [dt.datetime.strptime(str(d),'%Y').date() for d in years]


 plt.gca().xaxis.set_major_formatter(mdates.DateFormatter('%Y'))
 plt.gca().xaxis.set_major_locator(mdates.YearLocator())
 plt.plot(x, sales)
 plt.plot(x, expenses)
 plt.gcf().autofmt_xdate()
 plt.show()