python画图练习

1.plot绘制线型图

import matplotlib.pyplot as plt
import numpy as np
import pandas as pd
plt.rcParams['font.sans-serif'] = ['SimHei']
plt.rcParams['axes.unicode_minus'] = False
#plt.plot(x,y,s)   画出红色的正弦函数图
import numpy as np
x = np.linspace(0,2*np.pi,50)  #绘制出50个横坐标   (0,2Π)
y = np.sin(x)
plt.title('3105')
plt.plot(x,y,'r+')
plt.show()

 

2.pie函数绘制饼图

import matplotlib.pyplot as plt
labels = ['数学','语文','英语','政治']
sizes = [30,50,10,10]   #每一块的比例
colors =['yellow','green','blue','red']   #每一块的颜色
explode = (0.2,0.1,0,0)    #突出显示
plt.rcParams['font.sans-serif']=['SimHei']   #显示中文标签
plt.rcParams['axes.unicode_minus']=False
plt.pie(sizes,explode=explode,labels=labels,colors=colors,autopct='%1.1f%%',shadow=True,startangle=90)
plt.axis('equal')      #显示为圆，避免压缩成椭圆
plt.title('3105')
plt.show()

 

3.hist函数绘制二位条形直方图

import numpy as np
from matplotlib import pyplot as plt

x = np.random.randn(1000)   #随机生成1000个服从正态分布的随机数
plt.hist(x,10)
plt.title('3105')
plt.show()

 

 

 

 4.boxplot绘制箱型图

书本的例子

import pandas as pd
import matplotlib.pyplot as plt  # 导入图像库
#
catering_sale = '../data/catering_sale.xls'


data = pd.read_excel(catering_sale, index_col=u'日期')  # 读取数据，指定“日期”列为索引
describe = data.describe() #describe()函数能算出数据集的八个统计量
# print(describe)
count = describe.loc['count']   #loc统计对应的数值
# print("缺失值为:% d" % (len(data) - int(count)))  # 记录有201条，但count只有200，说明缺失值数为1

# 画出数据的箱线图

plt.rcParams['font.sans-serif'] = ['SimHei']  # 用来正常显示中文标签，plt.reParams是一个配置表
plt.rcParams['axes.unicode_minus'] = False  # 用来正常显示负号

plt.figure()
plt.title("3105")
p = data.boxplot(return_type='dict')  # 画箱线图,处理异常值
x = p['fliers'][0].get_xdata() # 'flies'即为异常值的标签
y = p['fliers'][0].get_ydata()
y.sort()

for i in range(len(x)):
  if i>0:
    plt.annotate(y[i], xy = (x[i],y[i]), xytext=(x[i]+0.05 -0.8/(y[i]-y[i-1]),y[i]))
  else:
    plt.annotate(y[i], xy = (x[i],y[i]), xytext=(x[i]+0.08,y[i]))

plt.show()