python - 在 sklearn.metrics.plot_confusion_matrix 中抑制科学记数法

Question

我试图很好地绘制一个混淆矩阵，所以我跟着 scikit-learn's newer version 0.22's in built plot confusion matrix function 。但是，我的混淆矩阵值的一个值是 153，但它在混淆矩阵图中显示为 1.5e+02:


在 scikit-learn's documentation 之后，我发现了这个名为 values_format 的参数，但我不知道如何操作这个参数，以便它可以抑制科学记数法。我的代码如下。

from sklearn import svm, datasets
from sklearn.model_selection import train_test_split
from sklearn.metrics import plot_confusion_matrix

# import some data to play with

X = pd.read_csv("datasets/X.csv")
y = pd.read_csv("datasets/y.csv")

class_names = ['Not Fraud (positive)', 'Fraud (negative)']

# Split the data into a training set and a test set
X_train, X_test, y_train, y_test = train_test_split(X, y, test_size=0.33, random_state=42)

# Run classifier, using a model that is too regularized (C too low) to see
# the impact on the results
logreg = LogisticRegression()
logreg.fit(X_train, y_train)


np.set_printoptions(precision=2)

# Plot non-normalized confusion matrix
titles_options = [("Confusion matrix, without normalization", None),
                  ("Normalized confusion matrix", 'true')]
for title, normalize in titles_options:
    disp = plot_confusion_matrix(logreg, X_test, y_test,
                                 display_labels=class_names,
                                 cmap=plt.cm.Greens,
                                 normalize=normalize, values_format = '{:.5f}'.format)
    disp.ax_.set_title(title)

    print(title)
    print(disp.confusion_matrix)

plt.show()

Answer 1

只需从调用参数声明中删除“.format”和 {} 括号:

disp = plot_confusion_matrix(logreg, X_test, y_test,
                                 display_labels=class_names,
                                 cmap=plt.cm.Greens,
                                 normalize=normalize, values_format = '.5f')

此外，您可以使用 '.5g' 来避免十进制 0

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