Python
1. 绘制一个柱状图，写出代码，要求：
x = [1,2,3,4,5,6,7,8]
y = [3,1,4,5,8,9,7,2]
图形最后形式如下图所示：
import matplotlib.pyplot as pltimport numpy as npx=[1,2,3,4,5,6,7,8]y=[3,1,4,5,8,9,7,2]name_lable=['A','B','C','D','E','F','G','H']plt.bar(range(len(y)),y,tick_label=name_lable)plt.show()
2. 绘制 x=(0,10)间 sin 的图像，设置线性为虚线。要求：写出代码 最后图形式为
import matplotlib.pyplot as pltimport numpy as npx=np.linspace(0,10,100)y=np.sin(x)plt.plot(x,y,color='b',linestyle='--',linewidth=1)plt.show()
3. 用散点图及颜色展示一组 4 维数据，代码如下,要求：给每行代码做注释，详细解释每个函数以及参数的意义
import numpy as np
import matplotlib.pyplot as plt
rng = np.random.RandomState(0)
x = rng.randn(100)
y = rng.randn(100)
colors = rng.rand(100)
sizes = 1000 * rng.rand(100)
plt.scatter(x, y, c=colors, s=sizes, alpha=0.3, cmap=‘viridis’)
plt.colorbar(); #
import numpy as npimport matplotlib.pyplot as pltrng=np.random.RandomState(0)#随机种子为0让每次运行随机数一样x=rng.randn(100)#赋值x产生100个随机数y=rng.randn(100)#赋值y产生100个随机数colors=rng.rand(100)#赋值颜色产生100个随机颜色sizes=1000*rng.rand(100)#大小设置为产生的随机值的1000倍plt.scatter(x,y,c=colors,s=sizes,alpha=0.3,cmap='viridis')#坐标（x,y）服从正态分布，(0,1)随机样本为点的颜色灰度值是，点的大小,颜色的映射plt.colorbar()#输出图形
4.用pandas实现下列列表.要求：
①编写代码实现下图内容
②并且显示前5行内容
③显示最后3行内容
④把下图按照age升序排序
import numpy as npimport pandas as pddate={"animal":["cat","cat","snake","dog","dog","cat","snake","cat","dog","dog"],"age":["2.5","3.0","0.5","NaN","5.0","2.0","4.5","NaN","7.0","3.0"],"priority":["yes","yes","no","yes","no","no","no","yes","no","no"],"visiits":["1","3","2","3","2","3","1","1","2","1"]}df=pd.DataFrame(date,index=['a','b','c','d','e','f','g','h','i','j'])print("①图")print(df)print("\n②显示前5行内容\n")print(df[0:5])print("\n③显示最后三行内容\n")print(df[-3:])print("\n④按照age升序排序\n")df_age=df.sort_values(by='age')print(df_age.head())
