Python scatter_matrix子坐标控制

df = DataFrame(np.random.randn(1000, 2), columns=['A','B'])
sm = scatter_matrix(df, alpha=0.2)
for subaxis in sm:
        for ax in subaxis:
            ax.xaxis.set_ticks([-2,2]) 
            ax.yaxis.set_ticks([-2,2])
            ax.set_xlim([-2,2])
#            ax.set_ylim([-2,2])
#            ax.set_ylabel("")
#            ax.set_xlabel("")