How to extract features using PCA in Python?
0

How to extract features using PCA in Python?

This recipe helps you extract features using PCA in Python
In [1]:
## How to extract features using PCA in Python
def Snippet_124():
    print()
    print(format('How to extract features using PCA in Python','*^82'))

    import warnings
    warnings.filterwarnings("ignore")

    # load libraries
    from sklearn import decomposition, datasets
    from sklearn.preprocessing import StandardScaler

    # Load the breast cancer dataset
    dataset = datasets.load_breast_cancer()

    # Load the features
    X = dataset.data

    # View the shape of the dataset
    print(); print(X.shape)
    print(); print(X)

    # Standardize Features
    sc = StandardScaler()

    # Fit the scaler to the features and transform
    X_std = sc.fit_transform(X)

    # View the new feature data's shape    
    print(); print(X_std.shape)
    print(); print(X_std)

    # Create a pca object with the 3 components
    pca = decomposition.PCA(n_components=3)

    # Fit the PCA and transform the data
    X_std_pca = pca.fit_transform(X_std)

    # View the new feature data's shape
    print(); print(X_std_pca.shape)
    print(); print(X_std_pca)

Snippet_124()
*******************How to extract features using PCA in Python********************

(569, 30)

[[1.799e+01 1.038e+01 1.228e+02 ... 2.654e-01 4.601e-01 1.189e-01]
 [2.057e+01 1.777e+01 1.329e+02 ... 1.860e-01 2.750e-01 8.902e-02]
 [1.969e+01 2.125e+01 1.300e+02 ... 2.430e-01 3.613e-01 8.758e-02]
 ...
 [1.660e+01 2.808e+01 1.083e+02 ... 1.418e-01 2.218e-01 7.820e-02]
 [2.060e+01 2.933e+01 1.401e+02 ... 2.650e-01 4.087e-01 1.240e-01]
 [7.760e+00 2.454e+01 4.792e+01 ... 0.000e+00 2.871e-01 7.039e-02]]

(569, 30)

[[ 1.09706398 -2.07333501  1.26993369 ...  2.29607613  2.75062224
   1.93701461]
 [ 1.82982061 -0.35363241  1.68595471 ...  1.0870843  -0.24388967
   0.28118999]
 [ 1.57988811  0.45618695  1.56650313 ...  1.95500035  1.152255
   0.20139121]
 ...
 [ 0.70228425  2.0455738   0.67267578 ...  0.41406869 -1.10454895
  -0.31840916]
 [ 1.83834103  2.33645719  1.98252415 ...  2.28998549  1.91908301
   2.21963528]
 [-1.80840125  1.22179204 -1.81438851 ... -1.74506282 -0.04813821
  -0.75120669]]

(569, 3)

[[ 9.19283683  1.94858275 -1.123163  ]
 [ 2.38780181 -3.76817263 -0.52928187]
 [ 5.73389628 -1.07517383 -0.55174676]
 ...
 [ 1.25617927 -1.90229641  0.56272681]
 [10.37479405  1.67201091 -1.87703905]
 [-5.47524329 -0.67063731  1.49044953]]