鸢尾花分类预测数据分析

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鸢尾花分类预测数据分析

戴千岩 2017-09-12 17:57:15 浏览777
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鸢尾花分类预测数据分析

  • 目标:根据未知种类鸢尾花的特征预测其种类
  • 数据:鸢尾花数据集
  • 分析:
    • 描述性分析
    • 探索性分析
      • 建模分析
      • 模型分析
      • 迭代分析
  • 成果:位置种类鸢尾花的预测结果
import numpy as np
import matplotlib.pyplot as plt
# import pandas as pd
from sklearn import neighbors, datasets


加载鸢尾花数据集

iris = datasets.load_iris()
iris
{'DESCR': 'Iris Plants Database\n====================\n\nNotes\n-----\nData Set Characteristics:\n    :Number of Instances: 150 (50 in each of three classes)\n    :Number of Attributes: 4 numeric, predictive attributes and the class\n    :Attribute Information:\n        - sepal length in cm\n        - sepal width in cm\n        - petal length in cm\n        - petal width in cm\n        - class:\n                - Iris-Setosa\n                - Iris-Versicolour\n                - Iris-Virginica\n    :Summary Statistics:\n\n    ============== ==== ==== ======= ===== ====================\n                    Min  Max   Mean    SD   Class Correlation\n    ============== ==== ==== ======= ===== ====================\n    sepal length:   4.3  7.9   5.84   0.83    0.7826\n    sepal width:    2.0  4.4   3.05   0.43   -0.4194\n    petal length:   1.0  6.9   3.76   1.76    0.9490  (high!)\n    petal width:    0.1  2.5   1.20  0.76     0.9565  (high!)\n    ============== ==== ==== ======= ===== ====================\n\n    :Missing Attribute Values: None\n    :Class Distribution: 33.3% for each of 3 classes.\n    :Creator: R.A. Fisher\n    :Donor: Michael Marshall (MARSHALL%PLU@io.arc.nasa.gov)\n    :Date: July, 1988\n\nThis is a copy of UCI ML iris datasets.\nhttp://archive.ics.uci.edu/ml/datasets/Iris\n\nThe famous Iris database, first used by Sir R.A Fisher\n\nThis is perhaps the best known database to be found in the\npattern recognition literature.  Fisher\'s paper is a classic in the field and\nis referenced frequently to this day.  (See Duda & Hart, for example.)  The\ndata set contains 3 classes of 50 instances each, where each class refers to a\ntype of iris plant.  One class is linearly separable from the other 2; the\nlatter are NOT linearly separable from each other.\n\nReferences\n----------\n   - Fisher,R.A. "The use of multiple measurements in taxonomic problems"\n     Annual Eugenics, 7, Part II, 179-188 (1936); also in "Contributions to\n     Mathematical Statistics" (John Wiley, NY, 1950).\n   - Duda,R.O., & Hart,P.E. (1973) Pattern Classification and Scene Analysis.\n     (Q327.D83) John Wiley & Sons.  ISBN 0-471-22361-1.  See page 218.\n   - Dasarathy, B.V. (1980) "Nosing Around the Neighborhood: A New System\n     Structure and Classification Rule for Recognition in Partially Exposed\n     Environments".  IEEE Transactions on Pattern Analysis and Machine\n     Intelligence, Vol. PAMI-2, No. 1, 67-71.\n   - Gates, G.W. (1972) "The Reduced Nearest Neighbor Rule".  IEEE Transactions\n     on Information Theory, May 1972, 431-433.\n   - See also: 1988 MLC Proceedings, 54-64.  Cheeseman et al"s AUTOCLASS II\n     conceptual clustering system finds 3 classes in the data.\n   - Many, many more ...\n',
 'data': array([[ 5.1,  3.5,  1.4,  0.2],
        [ 4.9,  3. ,  1.4,  0.2],
        [ 4.7,  3.2,  1.3,  0.2],
        [ 4.6,  3.1,  1.5,  0.2],
        [ 5. ,  3.6,  1.4,  0.2],
        [ 5.4,  3.9,  1.7,  0.4],
        [ 4.6,  3.4,  1.4,  0.3],
        [ 5. ,  3.4,  1.5,  0.2],
        [ 4.4,  2.9,  1.4,  0.2],
        [ 4.9,  3.1,  1.5,  0.1],
        [ 5.4,  3.7,  1.5,  0.2],
        [ 4.8,  3.4,  1.6,  0.2],
        [ 4.8,  3. ,  1.4,  0.1],
        [ 4.3,  3. ,  1.1,  0.1],
        [ 5.8,  4. ,  1.2,  0.2],
        [ 5.7,  4.4,  1.5,  0.4],
        [ 5.4,  3.9,  1.3,  0.4],
        [ 5.1,  3.5,  1.4,  0.3],
        [ 5.7,  3.8,  1.7,  0.3],
        [ 5.1,  3.8,  1.5,  0.3],
        [ 5.4,  3.4,  1.7,  0.2],
        [ 5.1,  3.7,  1.5,  0.4],
        [ 4.6,  3.6,  1. ,  0.2],
        [ 5.1,  3.3,  1.7,  0.5],
        [ 4.8,  3.4,  1.9,  0.2],
        [ 5. ,  3. ,  1.6,  0.2],
        [ 5. ,  3.4,  1.6,  0.4],
        [ 5.2,  3.5,  1.5,  0.2],
        [ 5.2,  3.4,  1.4,  0.2],
        [ 4.7,  3.2,  1.6,  0.2],
        [ 4.8,  3.1,  1.6,  0.2],
        [ 5.4,  3.4,  1.5,  0.4],
        [ 5.2,  4.1,  1.5,  0.1],
        [ 5.5,  4.2,  1.4,  0.2],
        [ 4.9,  3.1,  1.5,  0.1],
        [ 5. ,  3.2,  1.2,  0.2],
        [ 5.5,  3.5,  1.3,  0.2],
        [ 4.9,  3.1,  1.5,  0.1],
        [ 4.4,  3. ,  1.3,  0.2],
        [ 5.1,  3.4,  1.5,  0.2],
        [ 5. ,  3.5,  1.3,  0.3],
        [ 4.5,  2.3,  1.3,  0.3],
        [ 4.4,  3.2,  1.3,  0.2],
        [ 5. ,  3.5,  1.6,  0.6],
        [ 5.1,  3.8,  1.9,  0.4],
        [ 4.8,  3. ,  1.4,  0.3],
        [ 5.1,  3.8,  1.6,  0.2],
        [ 4.6,  3.2,  1.4,  0.2],
        [ 5.3,  3.7,  1.5,  0.2],
        [ 5. ,  3.3,  1.4,  0.2],
        [ 7. ,  3.2,  4.7,  1.4],
        [ 6.4,  3.2,  4.5,  1.5],
        [ 6.9,  3.1,  4.9,  1.5],
        [ 5.5,  2.3,  4. ,  1.3],
        [ 6.5,  2.8,  4.6,  1.5],
        [ 5.7,  2.8,  4.5,  1.3],
        [ 6.3,  3.3,  4.7,  1.6],
        [ 4.9,  2.4,  3.3,  1. ],
        [ 6.6,  2.9,  4.6,  1.3],
        [ 5.2,  2.7,  3.9,  1.4],
        [ 5. ,  2. ,  3.5,  1. ],
        [ 5.9,  3. ,  4.2,  1.5],
        [ 6. ,  2.2,  4. ,  1. ],
        [ 6.1,  2.9,  4.7,  1.4],
        [ 5.6,  2.9,  3.6,  1.3],
        [ 6.7,  3.1,  4.4,  1.4],
        [ 5.6,  3. ,  4.5,  1.5],
        [ 5.8,  2.7,  4.1,  1. ],
        [ 6.2,  2.2,  4.5,  1.5],
        [ 5.6,  2.5,  3.9,  1.1],
        [ 5.9,  3.2,  4.8,  1.8],
        [ 6.1,  2.8,  4. ,  1.3],
        [ 6.3,  2.5,  4.9,  1.5],
        [ 6.1,  2.8,  4.7,  1.2],
        [ 6.4,  2.9,  4.3,  1.3],
        [ 6.6,  3. ,  4.4,  1.4],
        [ 6.8,  2.8,  4.8,  1.4],
        [ 6.7,  3. ,  5. ,  1.7],
        [ 6. ,  2.9,  4.5,  1.5],
        [ 5.7,  2.6,  3.5,  1. ],
        [ 5.5,  2.4,  3.8,  1.1],
        [ 5.5,  2.4,  3.7,  1. ],
        [ 5.8,  2.7,  3.9,  1.2],
        [ 6. ,  2.7,  5.1,  1.6],
        [ 5.4,  3. ,  4.5,  1.5],
        [ 6. ,  3.4,  4.5,  1.6],
        [ 6.7,  3.1,  4.7,  1.5],
        [ 6.3,  2.3,  4.4,  1.3],
        [ 5.6,  3. ,  4.1,  1.3],
        [ 5.5,  2.5,  4. ,  1.3],
        [ 5.5,  2.6,  4.4,  1.2],
        [ 6.1,  3. ,  4.6,  1.4],
        [ 5.8,  2.6,  4. ,  1.2],
        [ 5. ,  2.3,  3.3,  1. ],
        [ 5.6,  2.7,  4.2,  1.3],
        [ 5.7,  3. ,  4.2,  1.2],
        [ 5.7,  2.9,  4.2,  1.3],
        [ 6.2,  2.9,  4.3,  1.3],
        [ 5.1,  2.5,  3. ,  1.1],
        [ 5.7,  2.8,  4.1,  1.3],
        [ 6.3,  3.3,  6. ,  2.5],
        [ 5.8,  2.7,  5.1,  1.9],
        [ 7.1,  3. ,  5.9,  2.1],
        [ 6.3,  2.9,  5.6,  1.8],
        [ 6.5,  3. ,  5.8,  2.2],
        [ 7.6,  3. ,  6.6,  2.1],
        [ 4.9,  2.5,  4.5,  1.7],
        [ 7.3,  2.9,  6.3,  1.8],
        [ 6.7,  2.5,  5.8,  1.8],
        [ 7.2,  3.6,  6.1,  2.5],
        [ 6.5,  3.2,  5.1,  2. ],
        [ 6.4,  2.7,  5.3,  1.9],
        [ 6.8,  3. ,  5.5,  2.1],
        [ 5.7,  2.5,  5. ,  2. ],
        [ 5.8,  2.8,  5.1,  2.4],
        [ 6.4,  3.2,  5.3,  2.3],
        [ 6.5,  3. ,  5.5,  1.8],
        [ 7.7,  3.8,  6.7,  2.2],
        [ 7.7,  2.6,  6.9,  2.3],
        [ 6. ,  2.2,  5. ,  1.5],
        [ 6.9,  3.2,  5.7,  2.3],
        [ 5.6,  2.8,  4.9,  2. ],
        [ 7.7,  2.8,  6.7,  2. ],
        [ 6.3,  2.7,  4.9,  1.8],
        [ 6.7,  3.3,  5.7,  2.1],
        [ 7.2,  3.2,  6. ,  1.8],
        [ 6.2,  2.8,  4.8,  1.8],
        [ 6.1,  3. ,  4.9,  1.8],
        [ 6.4,  2.8,  5.6,  2.1],
        [ 7.2,  3. ,  5.8,  1.6],
        [ 7.4,  2.8,  6.1,  1.9],
        [ 7.9,  3.8,  6.4,  2. ],
        [ 6.4,  2.8,  5.6,  2.2],
        [ 6.3,  2.8,  5.1,  1.5],
        [ 6.1,  2.6,  5.6,  1.4],
        [ 7.7,  3. ,  6.1,  2.3],
        [ 6.3,  3.4,  5.6,  2.4],
        [ 6.4,  3.1,  5.5,  1.8],
        [ 6. ,  3. ,  4.8,  1.8],
        [ 6.9,  3.1,  5.4,  2.1],
        [ 6.7,  3.1,  5.6,  2.4],
        [ 6.9,  3.1,  5.1,  2.3],
        [ 5.8,  2.7,  5.1,  1.9],
        [ 6.8,  3.2,  5.9,  2.3],
        [ 6.7,  3.3,  5.7,  2.5],
        [ 6.7,  3. ,  5.2,  2.3],
        [ 6.3,  2.5,  5. ,  1.9],
        [ 6.5,  3. ,  5.2,  2. ],
        [ 6.2,  3.4,  5.4,  2.3],
        [ 5.9,  3. ,  5.1,  1.8]]),
 'feature_names': ['sepal length (cm)',
  'sepal width (cm)',
  'petal length (cm)',
  'petal width (cm)'],
 'target': array([0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
        0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
        1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
        1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
        2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
        2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2]),
 'target_names': array(['setosa', 'versicolor', 'virginica'], 
       dtype='<U10')}


数据认知

type(iris)
sklearn.datasets.base.Bunch

数据集,样本150个

150行,4列

'data':array([
  [ 5.1,  3.5,  1.4,  0.2],
  [ 4.9,  3. ,  1.4,  0.2],
  [ 4.7,  3.2,  1.3,  0.2],
  [ 4.6,  3.1,  1.5,  0.2],
  [ 5. ,  3.6,  1.4,  0.2],
  [ 5.4,  3.9,  1.7,  0.4],
  ...
])

特征:4个

'feature_names': [
  'sepal length (cm)', #花萼长度
  'sepal width (cm)', #花萼宽度
  'petal length (cm)', #花瓣长度
  'petal width (cm)' #花瓣宽度
],

结果

标签1个:1行,150列

'target': array([
  0, 0, 0... 1, 1, 1... 2, 2, 2...
])

结果对应

'target_names': array([
  'setosa', # 0 山鸢尾
  'versicolor', # 1 变色鸢尾
  'virginica' # 2 维吉尼亚鸢尾
]}

描述性分析

se = iris.data[0:50] # 山鸢尾特征,50行
ve = iris.data[50:100] # 变色鸢尾特征,50行
vi = iris.data[100:150] # 维吉尼亚特征,50行
se

comb = [[0,1],[0,2],[0,3],[1,2],[1,3],[2,3]] #二维图像,4个特征两两组合

se[:,comb[0][0]] # 山鸢尾特征1,花萼长
array([ 5.1,  4.9,  4.7,  4.6,  5. ,  5.4,  4.6,  5. ,  4.4,  4.9,  5.4,
        4.8,  4.8,  4.3,  5.8,  5.7,  5.4,  5.1,  5.7,  5.1,  5.4,  5.1,
        4.6,  5.1,  4.8,  5. ,  5. ,  5.2,  5.2,  4.7,  4.8,  5.4,  5.2,
        5.5,  4.9,  5. ,  5.5,  4.9,  4.4,  5.1,  5. ,  4.5,  4.4,  5. ,
        5.1,  4.8,  5.1,  4.6,  5.3,  5. ])


图像绘制

plt.figure(1, figsize=(18,10)) 

for i in range(6):
    plt.subplot(231+i)
    plt.plot(se[:,comb[i][0]],se[:,comb[i][1]],'o',color='#ff0000')
    plt.plot(ve[:,comb[i][0]],ve[:,comb[i][1]],'^',color='#00ff00')
    plt.plot(vi[:,comb[i][0]],vi[:,comb[i][1]],'+',color='#ff00ff')

plt.show()

这里写图片描述


探索性分析

建模分析

# x轴,训练数据
x = iris.data
x
array([[ 5.1,  3.5,  1.4,  0.2],
       [ 4.9,  3. ,  1.4,  0.2],
       [ 4.7,  3.2,  1.3,  0.2],
       [ 4.6,  3.1,  1.5,  0.2],
       [ 5. ,  3.6,  1.4,  0.2],
       [ 5.4,  3.9,  1.7,  0.4],
       [ 4.6,  3.4,  1.4,  0.3],
       [ 5. ,  3.4,  1.5,  0.2],
       [ 4.4,  2.9,  1.4,  0.2],
       [ 4.9,  3.1,  1.5,  0.1],
       [ 5.4,  3.7,  1.5,  0.2],
       [ 4.8,  3.4,  1.6,  0.2],
       [ 4.8,  3. ,  1.4,  0.1],
       [ 4.3,  3. ,  1.1,  0.1],
       [ 5.8,  4. ,  1.2,  0.2],
       [ 5.7,  4.4,  1.5,  0.4],
       [ 5.4,  3.9,  1.3,  0.4],
       [ 5.1,  3.5,  1.4,  0.3],
       [ 5.7,  3.8,  1.7,  0.3],
       [ 5.1,  3.8,  1.5,  0.3],
       [ 5.4,  3.4,  1.7,  0.2],
       [ 5.1,  3.7,  1.5,  0.4],
       [ 4.6,  3.6,  1. ,  0.2],
       [ 5.1,  3.3,  1.7,  0.5],
       [ 4.8,  3.4,  1.9,  0.2],
       [ 5. ,  3. ,  1.6,  0.2],
       [ 5. ,  3.4,  1.6,  0.4],
       [ 5.2,  3.5,  1.5,  0.2],
       [ 5.2,  3.4,  1.4,  0.2],
       [ 4.7,  3.2,  1.6,  0.2],
       [ 4.8,  3.1,  1.6,  0.2],
       [ 5.4,  3.4,  1.5,  0.4],
       [ 5.2,  4.1,  1.5,  0.1],
       [ 5.5,  4.2,  1.4,  0.2],
       [ 4.9,  3.1,  1.5,  0.1],
       [ 5. ,  3.2,  1.2,  0.2],
       [ 5.5,  3.5,  1.3,  0.2],
       [ 4.9,  3.1,  1.5,  0.1],
       [ 4.4,  3. ,  1.3,  0.2],
       [ 5.1,  3.4,  1.5,  0.2],
       [ 5. ,  3.5,  1.3,  0.3],
       [ 4.5,  2.3,  1.3,  0.3],
       [ 4.4,  3.2,  1.3,  0.2],
       [ 5. ,  3.5,  1.6,  0.6],
       [ 5.1,  3.8,  1.9,  0.4],
       [ 4.8,  3. ,  1.4,  0.3],
       [ 5.1,  3.8,  1.6,  0.2],
       [ 4.6,  3.2,  1.4,  0.2],
       [ 5.3,  3.7,  1.5,  0.2],
       [ 5. ,  3.3,  1.4,  0.2],
       [ 7. ,  3.2,  4.7,  1.4],
       [ 6.4,  3.2,  4.5,  1.5],
       [ 6.9,  3.1,  4.9,  1.5],
       [ 5.5,  2.3,  4. ,  1.3],
       [ 6.5,  2.8,  4.6,  1.5],
       [ 5.7,  2.8,  4.5,  1.3],
       [ 6.3,  3.3,  4.7,  1.6],
       [ 4.9,  2.4,  3.3,  1. ],
       [ 6.6,  2.9,  4.6,  1.3],
       [ 5.2,  2.7,  3.9,  1.4],
       [ 5. ,  2. ,  3.5,  1. ],
       [ 5.9,  3. ,  4.2,  1.5],
       [ 6. ,  2.2,  4. ,  1. ],
       [ 6.1,  2.9,  4.7,  1.4],
       [ 5.6,  2.9,  3.6,  1.3],
       [ 6.7,  3.1,  4.4,  1.4],
       [ 5.6,  3. ,  4.5,  1.5],
       [ 5.8,  2.7,  4.1,  1. ],
       [ 6.2,  2.2,  4.5,  1.5],
       [ 5.6,  2.5,  3.9,  1.1],
       [ 5.9,  3.2,  4.8,  1.8],
       [ 6.1,  2.8,  4. ,  1.3],
       [ 6.3,  2.5,  4.9,  1.5],
       [ 6.1,  2.8,  4.7,  1.2],
       [ 6.4,  2.9,  4.3,  1.3],
       [ 6.6,  3. ,  4.4,  1.4],
       [ 6.8,  2.8,  4.8,  1.4],
       [ 6.7,  3. ,  5. ,  1.7],
       [ 6. ,  2.9,  4.5,  1.5],
       [ 5.7,  2.6,  3.5,  1. ],
       [ 5.5,  2.4,  3.8,  1.1],
       [ 5.5,  2.4,  3.7,  1. ],
       [ 5.8,  2.7,  3.9,  1.2],
       [ 6. ,  2.7,  5.1,  1.6],
       [ 5.4,  3. ,  4.5,  1.5],
       [ 6. ,  3.4,  4.5,  1.6],
       [ 6.7,  3.1,  4.7,  1.5],
       [ 6.3,  2.3,  4.4,  1.3],
       [ 5.6,  3. ,  4.1,  1.3],
       [ 5.5,  2.5,  4. ,  1.3],
       [ 5.5,  2.6,  4.4,  1.2],
       [ 6.1,  3. ,  4.6,  1.4],
       [ 5.8,  2.6,  4. ,  1.2],
       [ 5. ,  2.3,  3.3,  1. ],
       [ 5.6,  2.7,  4.2,  1.3],
       [ 5.7,  3. ,  4.2,  1.2],
       [ 5.7,  2.9,  4.2,  1.3],
       [ 6.2,  2.9,  4.3,  1.3],
       [ 5.1,  2.5,  3. ,  1.1],
       [ 5.7,  2.8,  4.1,  1.3],
       [ 6.3,  3.3,  6. ,  2.5],
       [ 5.8,  2.7,  5.1,  1.9],
       [ 7.1,  3. ,  5.9,  2.1],
       [ 6.3,  2.9,  5.6,  1.8],
       [ 6.5,  3. ,  5.8,  2.2],
       [ 7.6,  3. ,  6.6,  2.1],
       [ 4.9,  2.5,  4.5,  1.7],
       [ 7.3,  2.9,  6.3,  1.8],
       [ 6.7,  2.5,  5.8,  1.8],
       [ 7.2,  3.6,  6.1,  2.5],
       [ 6.5,  3.2,  5.1,  2. ],
       [ 6.4,  2.7,  5.3,  1.9],
       [ 6.8,  3. ,  5.5,  2.1],
       [ 5.7,  2.5,  5. ,  2. ],
       [ 5.8,  2.8,  5.1,  2.4],
       [ 6.4,  3.2,  5.3,  2.3],
       [ 6.5,  3. ,  5.5,  1.8],
       [ 7.7,  3.8,  6.7,  2.2],
       [ 7.7,  2.6,  6.9,  2.3],
       [ 6. ,  2.2,  5. ,  1.5],
       [ 6.9,  3.2,  5.7,  2.3],
       [ 5.6,  2.8,  4.9,  2. ],
       [ 7.7,  2.8,  6.7,  2. ],
       [ 6.3,  2.7,  4.9,  1.8],
       [ 6.7,  3.3,  5.7,  2.1],
       [ 7.2,  3.2,  6. ,  1.8],
       [ 6.2,  2.8,  4.8,  1.8],
       [ 6.1,  3. ,  4.9,  1.8],
       [ 6.4,  2.8,  5.6,  2.1],
       [ 7.2,  3. ,  5.8,  1.6],
       [ 7.4,  2.8,  6.1,  1.9],
       [ 7.9,  3.8,  6.4,  2. ],
       [ 6.4,  2.8,  5.6,  2.2],
       [ 6.3,  2.8,  5.1,  1.5],
       [ 6.1,  2.6,  5.6,  1.4],
       [ 7.7,  3. ,  6.1,  2.3],
       [ 6.3,  3.4,  5.6,  2.4],
       [ 6.4,  3.1,  5.5,  1.8],
       [ 6. ,  3. ,  4.8,  1.8],
       [ 6.9,  3.1,  5.4,  2.1],
       [ 6.7,  3.1,  5.6,  2.4],
       [ 6.9,  3.1,  5.1,  2.3],
       [ 5.8,  2.7,  5.1,  1.9],
       [ 6.8,  3.2,  5.9,  2.3],
       [ 6.7,  3.3,  5.7,  2.5],
       [ 6.7,  3. ,  5.2,  2.3],
       [ 6.3,  2.5,  5. ,  1.9],
       [ 6.5,  3. ,  5.2,  2. ],
       [ 6.2,  3.4,  5.4,  2.3],
       [ 5.9,  3. ,  5.1,  1.8]])
# y轴,标签,训练结果
y = iris.target
y
array([0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
       0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
       0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
       1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
       1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
       2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
       2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2])

模型训练

# knn训练
x = iris.data[:, 0:2] # 特征1,2
x
y = iris.target
y

clf = neighbors.KNeighborsClassifier(n_neighbors = 15)
clf.fit(x, y) # 模型训练
clf
KNeighborsClassifier(algorithm='auto', leaf_size=30, metric='minkowski',
           metric_params=None, n_jobs=1, n_neighbors=15, p=2,
           weights='uniform')
# knn预测
z = clf.predict(iris.data[:, 0:2]) # 特征1,2
z
array([0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
       0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
       0, 0, 0, 0, 2, 2, 2, 1, 2, 1, 2, 1, 2, 1, 1, 1, 1, 1, 1, 2, 1, 1, 2,
       1, 1, 2, 2, 2, 2, 2, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 1, 1, 1, 1,
       1, 1, 1, 1, 1, 2, 1, 1, 2, 1, 2, 2, 2, 2, 0, 2, 2, 2, 2, 2, 1, 1, 1,
       2, 2, 2, 2, 1, 2, 1, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2,
       1, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 1])

模型验证,正确率

# 预测正确率
correct = 0
for i in range(len(iris.data)):
    if z[i] == iris.target[i]:
        correct += 1
correct
correct/len(iris.data)
0.8066666666666666

迭代优化

# knn训练
x = np.c_[iris.data[:, 2], iris.data[:, 3]] # 特征3,4
y = iris.target

clf = neighbors.KNeighborsClassifier(n_neighbors = 15)
clf.fit(x,y)
clf
KNeighborsClassifier(algorithm='auto', leaf_size=30, metric='minkowski',
           metric_params=None, n_jobs=1, n_neighbors=15, p=2,
           weights='uniform')
#knn预测

z = clf.predict(np.c_[iris.data[:,2],iris.data[:,3]]) #特征3,4
z
array([0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
       0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
       0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
       1, 2, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1,
       1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 2, 2,
       2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2,
       2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2])
#预测正确率

correct = 0
for i in range(len(iris.data)):
    if z[i] == iris.target[i]:
        correct += 1

correct/len(iris.data)
0.96

机器学习过程中
* 特征最重要
* 机器学习算法,次要(信息熵)
* 热力学熵,是衡量物质混乱程度的一种度量
* 信息学熵,衡量信息大小的一种度量(出人意料,与众不同),香农

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