Python 中，matplotlib绘图无法显示中文的问题

在python中，默认情况下是无法显示中文的，如下代码：

import matplotlib.pyplot as plt

# 定义文本框和箭头格式
decisionNode = dict(boxstyle = "sawtooth", fc = "0.8")
leafNode = dict(boxstyle = "round4", fc = "0.8")
arrow_args = dict(arrowstyle = "<-")

# 绘制带箭头的注解
def plotNode(nodeTxt, centerPt, parentPt, nodeType) :
	createPlot.ax1.annotate(nodeTxt, xy = parentPt, xycoords = 'axes fraction', xytext = centerPt, textcoords = 'axes fraction', va = 'center', ha = 'center', bbox = nodeType, arrowprops = arrow_args)

def createPlot() :
	fig = plt.figure(1, facecolor='white')
	fig.clf()
	createPlot.ax1 = plt.subplot(111, frameon = False)
	plotNode(U'决策节点', (0.5, 0.1), (0.1, 0.5), decisionNode)
	plotNode(U'叶节点', (0.8, 0.1), (0.3, 0.8), leafNode)
	plt.show()

createPlot()

得到图像如下：

产生中文乱码的原因就是字体的默认设置中并没有中文字体，所以我们只要手动添加中文字体的名称就可以了

手动增加如下代码

from pylab import *
mpl.rcParams['font.sans-serif'] = ['SimHei']

源代码修改如下：

import matplotlib.pyplot as plt

from pylab import *
mpl.rcParams['font.sans-serif'] = ['SimHei']

# 定义文本框和箭头格式
decisionNode = dict(boxstyle = "sawtooth", fc = "0.8")
leafNode = dict(boxstyle = "round4", fc = "0.8")
arrow_args = dict(arrowstyle = "<-")

# 绘制带箭头的注解
def plotNode(nodeTxt, centerPt, parentPt, nodeType) :
	createPlot.ax1.annotate(nodeTxt, xy = parentPt, xycoords = 'axes fraction', xytext = centerPt, textcoords = 'axes fraction', va = 'center', ha = 'center', bbox = nodeType, arrowprops = arrow_args)

def createPlot() :
	fig = plt.figure(1, facecolor='white')
	fig.clf()
	createPlot.ax1 = plt.subplot(111, frameon = False)
	plotNode(U'决策节点', (0.5, 0.1), (0.1, 0.5), decisionNode)
	plotNode(U'叶节点', (0.8, 0.1), (0.3, 0.8), leafNode)
	plt.show()
createPlot()

最终得到图像

成功！