matplotlib:plt.bar

import numpy as np
import matplotlib
matplotlib.use(“TkAgg”)
import matplotlib.pyplot as plt

n=12
X=np.arange(n)
Y1=(1-X/float(n))*np.random.uniform(0.5,1.0,n)
Y2=(1-X/float(n))*np.random.uniform(0.5,1.0,n)

plt.bar(X,+Y1,facecolor=“r”,edgecolor=“white”,alpha=0.6)
plt.bar(X,-Y2,facecolor=“b”,edgecolor=“white”,alpha=0.6)

for x,y in zip(X,Y1):
#ha:horizontal alignment
plt.text(x+0.4,y+0.05,"%.2f" % y,ha=“center”,va=“bottom”)

for x,y in zip(X,Y1):
#ha:horizontal alignment
plt.text(x+0.4,-y-0.05,"%.2f" % y,ha=“center”,va=“top”)

plt.xlim(-.5,n) #设置X轴的长度
plt.xticks(())#隐藏X轴的ticks
plt.ylim(-1.25,1.25)#设置Y轴的长度
plt.yticks(())#隐藏Y轴的ticks

plt.show()