create some data

x = np.linspace(-np.pi,np.pi,100)y = np.cos(2.5*x)fig = plt.figure()ax = fig.add_subplot(111)ax.plot(x,y, mfc='orange', mec='orange', marker='.')# using 'spines', new in Matplotlib 1.0ax.spines['left'].set_position('zero')ax.spines['right'].set_color('none')ax.spines['bottom'].set_position('zero')ax.spines['top'].set_color('none')ax.spines['left'].set_smart_bounds(True)ax.spines['bottom'].set_smart_bounds(True)ax.xaxis.set_ticks_position('bottom')ax.yaxis.set_ticks_position('left')ax.axhline(linewidth=2, color='blue')ax.axvline(linewidth=2, color='blue')show()