#Função que permitirá rankear as features mais importantes em um barhplot
def ranks_PCA (x_train, y_train, features_train, RESULT_PATH='Results'):
    print("\nMétodo PCA")

    pca = PCA(n_components=58)

    imp_array = np.array(pca.components_)
    imp_order = imp_array.argsort()
    ranks = imp_order.argsort()

    # Plot PCA
    imp = pd.Series(pca.components_, index=x_train.columns)
    imp = imp.sort_values()

    plt.title("Feature importance using PCA")
    # plt.show()
    plt.savefig(RESULT_PATH + '/ranks_DT.png', bbox_inches='tight')

    return ranks

#Função para predição das features dos dados de teste
def predict_PCA(x_test_sel, k_vetor, y_train):
    model = decomposition.PCA()
    model.fit(k_vetor, y_train)
    y_predict = model.predict(x_test_sel)

#Função que calcula o ranking dos dados de treinamento
ranks4 = frk.ranks_PCA(x_train, y_train, features_train, RESULT_PATH)

I have doubts if this implementation is correct to obtain more important features. When trying to run this code, I get the following error:

Traceback (most recent call last): File "feat_test.py", line 235, in 'Results/PDBbind2018_F58_Delta_pKd') File "feat_test.py", line 78, in run_experiment ranks4 = frk.ranks_PCA(x_train, y_train, features_train, RESULT_PATH) File "C:\Users\Patricia\Desktop\VT-58 - Cópia\feature-importance\feature_rank_ ensemble\Scripts\feature_ranks.py", line 121, in ranks_PCA imp = pd.Series(pca.components_, index=x_train.columns) File "C:\Users\Patricia\Desktop\VT-58 - Cópia\feature-importance\feature_rank_ ensemble\env\lib\site-packages\pandas\core\series.py", line 305, in init data = sanitize_array(data, index, dtype, copy, raise_cast_failure=True) File "C:\Users\Patricia\Desktop\VT-58 - Cópia\feature-importance\feature_rank_ ensemble\env\lib\site-packages\pandas\core\construction.py", line 482, in saniti ze_array raise Exception("Data must be 1-dimensional")

Can anybody help me?

  • 2
    $\begingroup$ it's not possible to correlate your error traceback with your code, so it's difficult to understand where the error comes from. you'll get more useful answers if you can create a minimal reproducible example: stackoverflow.com/help/minimal-reproducible-example $\endgroup$ Mar 6, 2020 at 3:39

1 Answer 1


pca.components_ is a 2d array, so you cannot make a Series out of it.

  • $\begingroup$ simple answer but it really helped me to find the error, thank you very much. $\endgroup$ Mar 7, 2020 at 1:10

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