matplotlib函数库使用bar绘制柱状图

#coding=utf-8import numpy as npimport matplotlib.pyplot as pltx=np.arange(10)y1=(1-x/float(10))*np.random.uniform(0.5,1,10)y2=(1-x/float(10))*np.random.uniform(0.5,1,10)plt.bar(x,y1,facecolor='#9999ff',edgecolor='white')plt.bar(x,-y2,facecolor='#ff9999',edgecolor='white')a=zip(x,y1)b=zip(x,y2)for x,y in a:    plt.text(x,y+0.1,'%.2f'%y,ha='center',va='bottom')    #为直方图添加注释标签for x,y in b:    plt.text(x,-y-0.1,'%.2f'%y,ha='center',va='bottom')     #为直方图添加注释标签#设置柱状图存放x,y数据plt.xlim((-1,10))plt.ylim((-1,1.2))#设置x,y轴范围plt.xticks(())plt.yticks(())#不显示x,y轴刻度plt.show()