numpy

c = np.array([a,b])#建立二维数组
c
type(c)
type(c[0])
c.dtype
c[1].dtype

结果：

array([[10, 11, 12, 13, 14],
       [ 0,  1,  2,  3,  4]])

numpy.ndarray

dtype('int32')

1. 安装scipy，numpy，sklearn包

import numpy as np
a = list(range(10,15))
b = np.arange(5)
a
b
a*2
b*2
a+b
b.shape
b.dtype

结果：

[10, 11, 12, 13, 14]

array([0, 1, 2, 3, 4])

[10, 11, 12, 13, 14, 10, 11, 12, 13, 14]

array([0, 2, 4, 6, 8])

array([10, 12, 14, 16, 18])

(5,)

dtype('int32')

2. 从sklearn包自带的数据集中读出鸢尾花数据集data

from sklearn.datasets import load_iris
data = load_iris()


3.查看data类型，包含哪些数据
print(type(data))
print(data.keys())

结果：

4.取出鸢尾花特征和鸢尾花类别数据，查看其形状及数据类型
iris_feature=data['data'],data['feature_names']  
print("形状：",iris_feature)

iris_target=data.target  
print("类型:",iris_target) 
type(iris_feature)
type(iris_target)

结果：

5.取出所有花的花萼长度(cm)的数据

iris_len=np.array(list(len[0] for len in data['data']))
print("花萼长度：",iris_len)

结果：

6.取出所有花的花瓣长度(cm)+花瓣宽度(cm)的数据

iris1_len=np.array(list(len[2] for len in data['data']))  
iris1_len.resize((10,15))
print("花瓣长：",iris1_len)

结果：

iris1_wid=np.array(list(len[3] for len in data['data']))
iris1_wid.resize((10,15))
print("花瓣宽：",iris1_wid)

结果：

7.取出某朵花的四个特征及其类别。

print("第三朵花数据：",data['data'][2],data['target'][2])

结果：

第三朵花数据： [4.7 3.2 1.3 0.2] 0

8.将所有花的特征和类别分成三组，每组50个
iris_setosa=[]      #定义三个新列表用于存放数据
iris_versicolor=[]
iris_virginica=[]

for i in range(0,150):  
    if data['target'][i]==0:
        data1=data['data'][i].tolist()
        data1.append('setosa')
        iris_setosa.append(data1)
    elif data['target'][i]==1:
        data1=data['data'][i].tolist()
        data1.append('versicolor')
        iris_versicolor.append(data1)
    else:
        data1=data['data'][i].tolist()
        data1.append('virginica')
        iris_virginica.append(data1)

9.生成新的数组，每个元素包含四个特征+类别
data2=np.array([iris_setosa,iris_versicolor,iris_virginica]) 
print(data2)

结果：

[[['5.1' '3.5' '1.4' '0.2' 'setosa']
  ['4.9' '3.0' '1.4' '0.2' 'setosa']
  ['4.7' '3.2' '1.3' '0.2' 'setosa']
  ['4.6' '3.1' '1.5' '0.2' 'setosa']
  ['5.0' '3.6' '1.4' '0.2' 'setosa']
  ['5.4' '3.9' '1.7' '0.4' 'setosa']
  ['4.6' '3.4' '1.4' '0.3' 'setosa']
  ['5.0' '3.4' '1.5' '0.2' 'setosa']
  ['4.4' '2.9' '1.4' '0.2' 'setosa']
  ['4.9' '3.1' '1.5' '0.1' 'setosa']
  ['5.4' '3.7' '1.5' '0.2' 'setosa']
  ['4.8' '3.4' '1.6' '0.2' 'setosa']
  ['4.8' '3.0' '1.4' '0.1' 'setosa']
  ['4.3' '3.0' '1.1' '0.1' 'setosa']
  ['5.8' '4.0' '1.2' '0.2' 'setosa']
  ['5.7' '4.4' '1.5' '0.4' 'setosa']
  ['5.4' '3.9' '1.3' '0.4' 'setosa']
  ['5.1' '3.5' '1.4' '0.3' 'setosa']
  ['5.7' '3.8' '1.7' '0.3' 'setosa']
  ['5.1' '3.8' '1.5' '0.3' 'setosa']
  ['5.4' '3.4' '1.7' '0.2' 'setosa']
  ['5.1' '3.7' '1.5' '0.4' 'setosa']
  ['4.6' '3.6' '1.0' '0.2' 'setosa']
  ['5.1' '3.3' '1.7' '0.5' 'setosa']
  ['4.8' '3.4' '1.9' '0.2' 'setosa']
  ['5.0' '3.0' '1.6' '0.2' 'setosa']
  ['5.0' '3.4' '1.6' '0.4' 'setosa']
  ['5.2' '3.5' '1.5' '0.2' 'setosa']
  ['5.2' '3.4' '1.4' '0.2' 'setosa']
  ['4.7' '3.2' '1.6' '0.2' 'setosa']
  ['4.8' '3.1' '1.6' '0.2' 'setosa']
  ['5.4' '3.4' '1.5' '0.4' 'setosa']
  ['5.2' '4.1' '1.5' '0.1' 'setosa']
  ['5.5' '4.2' '1.4' '0.2' 'setosa']
  ['4.9' '3.1' '1.5' '0.1' 'setosa']
  ['5.0' '3.2' '1.2' '0.2' 'setosa']
  ['5.5' '3.5' '1.3' '0.2' 'setosa']
  ['4.9' '3.1' '1.5' '0.1' 'setosa']
  ['4.4' '3.0' '1.3' '0.2' 'setosa']
  ['5.1' '3.4' '1.5' '0.2' 'setosa']
  ['5.0' '3.5' '1.3' '0.3' 'setosa']
  ['4.5' '2.3' '1.3' '0.3' 'setosa']
  ['4.4' '3.2' '1.3' '0.2' 'setosa']
  ['5.0' '3.5' '1.6' '0.6' 'setosa']
  ['5.1' '3.8' '1.9' '0.4' 'setosa']
  ['4.8' '3.0' '1.4' '0.3' 'setosa']
  ['5.1' '3.8' '1.6' '0.2' 'setosa']
  ['4.6' '3.2' '1.4' '0.2' 'setosa']
  ['5.3' '3.7' '1.5' '0.2' 'setosa']
  ['5.0' '3.3' '1.4' '0.2' 'setosa']]

 [['7.0' '3.2' '4.7' '1.4' 'versicolor']
  ['6.4' '3.2' '4.5' '1.5' 'versicolor']
  ['6.9' '3.1' '4.9' '1.5' 'versicolor']
  ['5.5' '2.3' '4.0' '1.3' 'versicolor']
  ['6.5' '2.8' '4.6' '1.5' 'versicolor']
  ['5.7' '2.8' '4.5' '1.3' 'versicolor']
  ['6.3' '3.3' '4.7' '1.6' 'versicolor']
  ['4.9' '2.4' '3.3' '1.0' 'versicolor']
  ['6.6' '2.9' '4.6' '1.3' 'versicolor']
  ['5.2' '2.7' '3.9' '1.4' 'versicolor']
  ['5.0' '2.0' '3.5' '1.0' 'versicolor']
  ['5.9' '3.0' '4.2' '1.5' 'versicolor']
  ['6.0' '2.2' '4.0' '1.0' 'versicolor']
  ['6.1' '2.9' '4.7' '1.4' 'versicolor']
  ['5.6' '2.9' '3.6' '1.3' 'versicolor']
  ['6.7' '3.1' '4.4' '1.4' 'versicolor']
  ['5.6' '3.0' '4.5' '1.5' 'versicolor']
  ['5.8' '2.7' '4.1' '1.0' 'versicolor']
  ['6.2' '2.2' '4.5' '1.5' 'versicolor']
  ['5.6' '2.5' '3.9' '1.1' 'versicolor']
  ['5.9' '3.2' '4.8' '1.8' 'versicolor']
  ['6.1' '2.8' '4.0' '1.3' 'versicolor']
  ['6.3' '2.5' '4.9' '1.5' 'versicolor']
  ['6.1' '2.8' '4.7' '1.2' 'versicolor']
  ['6.4' '2.9' '4.3' '1.3' 'versicolor']
  ['6.6' '3.0' '4.4' '1.4' 'versicolor']
  ['6.8' '2.8' '4.8' '1.4' 'versicolor']
  ['6.7' '3.0' '5.0' '1.7' 'versicolor']
  ['6.0' '2.9' '4.5' '1.5' 'versicolor']
  ['5.7' '2.6' '3.5' '1.0' 'versicolor']
  ['5.5' '2.4' '3.8' '1.1' 'versicolor']
  ['5.5' '2.4' '3.7' '1.0' 'versicolor']
  ['5.8' '2.7' '3.9' '1.2' 'versicolor']
  ['6.0' '2.7' '5.1' '1.6' 'versicolor']
  ['5.4' '3.0' '4.5' '1.5' 'versicolor']
  ['6.0' '3.4' '4.5' '1.6' 'versicolor']
  ['6.7' '3.1' '4.7' '1.5' 'versicolor']
  ['6.3' '2.3' '4.4' '1.3' 'versicolor']
  ['5.6' '3.0' '4.1' '1.3' 'versicolor']
  ['5.5' '2.5' '4.0' '1.3' 'versicolor']
  ['5.5' '2.6' '4.4' '1.2' 'versicolor']
  ['6.1' '3.0' '4.6' '1.4' 'versicolor']
  ['5.8' '2.6' '4.0' '1.2' 'versicolor']
  ['5.0' '2.3' '3.3' '1.0' 'versicolor']
  ['5.6' '2.7' '4.2' '1.3' 'versicolor']
  ['5.7' '3.0' '4.2' '1.2' 'versicolor']
  ['5.7' '2.9' '4.2' '1.3' 'versicolor']
  ['6.2' '2.9' '4.3' '1.3' 'versicolor']
  ['5.1' '2.5' '3.0' '1.1' 'versicolor']
  ['5.7' '2.8' '4.1' '1.3' 'versicolor']]

 [['6.3' '3.3' '6.0' '2.5' 'virginica']
  ['5.8' '2.7' '5.1' '1.9' 'virginica']
  ['7.1' '3.0' '5.9' '2.1' 'virginica']
  ['6.3' '2.9' '5.6' '1.8' 'virginica']
  ['6.5' '3.0' '5.8' '2.2' 'virginica']
  ['7.6' '3.0' '6.6' '2.1' 'virginica']
  ['4.9' '2.5' '4.5' '1.7' 'virginica']
  ['7.3' '2.9' '6.3' '1.8' 'virginica']
  ['6.7' '2.5' '5.8' '1.8' 'virginica']
  ['7.2' '3.6' '6.1' '2.5' 'virginica']
  ['6.5' '3.2' '5.1' '2.0' 'virginica']
  ['6.4' '2.7' '5.3' '1.9' 'virginica']
  ['6.8' '3.0' '5.5' '2.1' 'virginica']
  ['5.7' '2.5' '5.0' '2.0' 'virginica']
  ['5.8' '2.8' '5.1' '2.4' 'virginica']
  ['6.4' '3.2' '5.3' '2.3' 'virginica']
  ['6.5' '3.0' '5.5' '1.8' 'virginica']
  ['7.7' '3.8' '6.7' '2.2' 'virginica']
  ['7.7' '2.6' '6.9' '2.3' 'virginica']
  ['6.0' '2.2' '5.0' '1.5' 'virginica']
  ['6.9' '3.2' '5.7' '2.3' 'virginica']
  ['5.6' '2.8' '4.9' '2.0' 'virginica']
  ['7.7' '2.8' '6.7' '2.0' 'virginica']
  ['6.3' '2.7' '4.9' '1.8' 'virginica']
  ['6.7' '3.3' '5.7' '2.1' 'virginica']
  ['7.2' '3.2' '6.0' '1.8' 'virginica']
  ['6.2' '2.8' '4.8' '1.8' 'virginica']
  ['6.1' '3.0' '4.9' '1.8' 'virginica']
  ['6.4' '2.8' '5.6' '2.1' 'virginica']
  ['7.2' '3.0' '5.8' '1.6' 'virginica']
  ['7.4' '2.8' '6.1' '1.9' 'virginica']
  ['7.9' '3.8' '6.4' '2.0' 'virginica']
  ['6.4' '2.8' '5.6' '2.2' 'virginica']
  ['6.3' '2.8' '5.1' '1.5' 'virginica']
  ['6.1' '2.6' '5.6' '1.4' 'virginica']
  ['7.7' '3.0' '6.1' '2.3' 'virginica']
  ['6.3' '3.4' '5.6' '2.4' 'virginica']
  ['6.4' '3.1' '5.5' '1.8' 'virginica']
  ['6.0' '3.0' '4.8' '1.8' 'virginica']
  ['6.9' '3.1' '5.4' '2.1' 'virginica']
  ['6.7' '3.1' '5.6' '2.4' 'virginica']
  ['6.9' '3.1' '5.1' '2.3' 'virginica']
  ['5.8' '2.7' '5.1' '1.9' 'virginica']
  ['6.8' '3.2' '5.9' '2.3' 'virginica']
  ['6.7' '3.3' '5.7' '2.5' 'virginica']
  ['6.7' '3.0' '5.2' '2.3' 'virginica']
  ['6.3' '2.5' '5.0' '1.9' 'virginica']
  ['6.5' '3.0' '5.2' '2.0' 'virginica']
  ['6.2' '3.4' '5.4' '2.3' 'virginica']
  ['5.9' '3.0' '5.1' '1.8' 'virginica']]]