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Machine Learning/머신러닝 완벽가이드 for Python

ch 2.3 사이킷런의 내장 예제 데이터 (실습)

1  사이킷런 내장 데이터인 iris_data 구조를 확인해보자

 

from sklearn.datasets import load_iris

iris_data = load_iris()

# load_iris()는 클래스 / iris_data는 인스턴스

print(type(iris_data))
iris_data
더보기
 
{'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, 0.2],
                [5. , 3.2, 1.2, 0.2],
                [5.5, 3.5, 1.3, 0.2],
                [4.9, 3.6, 1.4, 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]]),
 '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]),
 'frame': None,
 'target_names': array(['setosa', 'versicolor', 'virginica'], dtype='<U10'),
 'DESCR': '.. _iris_dataset:\n\nIris plants dataset\n--------------------\n\n**Data Set Characteristics:**\n\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                \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\nThe famous Iris database, first used by Sir R.A. Fisher. The dataset is taken\nfrom Fisher\'s paper. Note that it\'s the same as in R, but not as in the UCI\nMachine Learning Repository, which has two wrong data points.\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\n.. topic:: References\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 ...',
 'feature_names': ['sepal length (cm)',
  'sepal width (cm)',
  'petal length (cm)',
  'petal width (cm)'],
 'filename': 'iris.csv',
 'data_module': 'sklearn.datasets.data'}

 

# 붓꽃 데이터 세트의 키들
iris_data.keys()

# iris_data.keys() -> iris_data의 인스턴스 안의 메소드(keys)

>>> dict_keys(['data', 'target', 'frame', 'target_names', 'DESCR', 'feature_names', 'filename', 'data_module'])

 

 

키는 보통 data, target, target_name, feature_names, DESCR로 구성돼 있습니다.

개별 키가 가리키는 의미는 다음과 같습니다.

  • data는 피처의 데이터 세트를 가리킵니다.
  • target은 분류 시 레이블 값, 회귀일 때는 숫자 결괏값 데이터 세트입니다..
  • target_names는 개별 레이블의 이름을 나타냅니다.
  • feature_names는 피처의 이름을 나타냅니다.
  • DESCR은 데이터 세트에 대한 설명과 각 피처의 설명을 나타냅니다.

 

# iris_data.feature_names 확인
print(type(iris_data.feature_names))

>>> <class 'list'>

 

print(len(iris_data['feature_names']))
>>> 4

print(iris_data['feature_names'])
>>> ['sepal length (cm)', 'sepal width (cm)', 'petal length (cm)', 'petal width (cm)']

 

# iris_data.target_names 확인
print(type(iris_data["target_names"]))

>>> <class 'numpy.ndarray'>

 

print(iris_data["target_names"].shape)
print(iris_data["target_names"])

>>> (3,)
['setosa' 'versicolor' 'virginica']

 

# iris_data.data 확인
print(type(iris_data["data"]))

>>> <class 'numpy.ndarray'>

print(iris_data["data"].shape)
print(iris_data['data'])
더보기
(150, 4)
[[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 0.2]
 [5.  3.2 1.2 0.2]
 [5.5 3.5 1.3 0.2]
 [4.9 3.6 1.4 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]]

 

 

# iris_data.target 확인
print(type(iris_data["target"]))

>>> <class 'numpy.ndarray'>

 

print(iris_data["target"].shape)

>>> (150,)

print(iris_data["target"])

>>>

[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]