使用x轴python上的日期设置轴限制

Question

我难以在散点图上更改x轴

events_perday = df[['Dates','Category']].query('Category == "LARCENY/THEFT"').groupby(['Dates']).count()
events_perday = events_perday.resample('D',how=sum)
events_perday.dropna(inplace = True)

N = 2248
colors = np.linspace(0,1,N)
mpl.rcParams['ytick.labelsize'] = 14
mpl.rcParams['xtick.labelsize'] = 14
fig = plt.figure(figsize=(16,9))
ax = fig.add_subplot(111,axisbg='black')
ax.grid(b=False)

#plt.xlim([2003-01-06,'2015-05-13'])
ax.scatter(events_perday.index, events_perday['Category'],c=colors ,cmap = "winter")

http://i.imgur.com/dVPIHU6.png

正如你所看到的，我只需要稍微提一下，但我一直在研究，但仍然陷入困境：/