python - ValueError: unknown format is not supported : ROC Curve

Question

I have just updated python version from 3.5 to 3.7 and getting an error in constructing ROC curve. I did not change anything in code but it gives some unknown error

Code

# ROC Curve

from sklearn.metrics import confusion_matrix, accuracy_score, roc_auc_score, roc_curve
y_pred_proba = predictions[::, 1]
print("y_pred_proba", y_pred_proba)
print("y_test", y_test)

fpr, tpr, _ = roc_curve(y_test, y_pred_proba)
auc = roc_auc_score(y_test, y_pred_proba)

plt.figure(figsize=(7, 3))

Values

y_pred_proba [0.1746994 0.22792926 0.60020134 0.60857445 0.38630289 0.16318228 0.20503542 0.76781874 0.89951127 0.13657112 0.36836385 0.23833946 0.43924601 0.9874083 0.98404103 0.1003149 0.94596688 0.36480605 0.48716601 0.04158647 0.8624937 0.93881636 0.54065999 0.38538261 0.48002784 0.9874083 0.76781874 0.95791353 0.48002784 0.2448756 0.98404103 0.06473023 0.34080482 0.11897602 0.07883822 0.08000581 0.38630289 0.2546955 0.95515939 0.47123327 0.93544655 0.52027235 0.23231433 0.45185196 0.78456432 0.92415415 0.22408711 0.82322069 0.12670252 0.50150037 0.2546955 0.93881636 0.33043862 0.52027235 0.07964735 0.11961717 0.79551265 0.0378607 0.34080482 0.87411928 0.85397911 0.9874083 0.18885285 0.93140091 0.87411928 0.52027235 0.48716601 0.19411124 0.06473023 0.79551265 0.76781874 0.81180605 0.06833817 0.45406719 0.54006639 0.48002784 0.12468554 0.38630289 0.18068918 0.9874083 0.79551265 0.43924601 0.86979492 0.15120609 0.56046085 0.27958234 0.50261158 0.23231433 0.42496329 0.98404103 0.93881636 0.96244002 0.38049589 0.9874083 0.38354959 0.8624937 0.48716601 0.89951127 0.98404103 0.37245044 0.38630289 0.49835809 0.9874083 0.27773467 0.98404103 0.40968608 0.3587635 0.1003149 0.2572435 0.52492011 0.19933781 0.38538261 0.24401876 0.06473023 0.82322069]

y_test [1 0 1 0 0 1 0 0 1 0 0 0 0 1 1 0 1 0 0 0 1 1 1 0 1 1 1 0 0 0 1 0 0 0 0 1 1 0 1 1 1 0 0 1 0 1 0 1 0 1 1 1 1 1 0 0 1 0 0 1 0 1 0 1 1 1 1 0 0 1 1 1 0 1 1 0 0 0 0 1 1 0 1 0 0 0 0 0 0 1 1 1 0 1 0 1 1 1 1 0 0 1 1 0 1 0 0 0 1 0 0 0 0 0 1 0 0 0 0 1 0 1 0 0 0 1 1 0 1 0 0 1 0 0 0 0 1 1 1 1 1 0 1 0 0 0 0 0 0 1 1 1 0 0 1 1 1 01]

Traceback (most recent call last):
  File "/home/khawar/deepface/tests/Ensemble-Face-Recognition.py", line 897, in <module>
    fpr, tpr, _ = roc_curve(y_test, y_pred_proba)
  File "/home/khawar/.local/lib/python3.6/site-packages/sklearn/utils/validation.py", line 72, in inner_f
    return f(**kwargs)
  File "/home/khawar/.local/lib/python3.6/site-packages/sklearn/metrics/_ranking.py", line 776, in roc_curve
    y_true, y_score, pos_label=pos_label, sample_weight=sample_weight)
  File "/home/khawar/.local/lib/python3.6/site-packages/sklearn/metrics/_ranking.py", line 539, in _binary_clf_curve
    raise ValueError("{0} format is not supported".format(y_type))
ValueError: unknown format is not supported

Answer 1

if we print the value of type_of_target(y_test) the output value is "unknown". Now, we have to change the unknown to integer. So we will do like this

y_test = y_test.astype(int)

Overall Code

from sklearn.metrics import confusion_matrix, accuracy_score, roc_auc_score, roc_curve

y_pred_proba = predictions[::, 1]
y_test = y_test.astype(int)


fpr, tpr, _ = roc_curve(y_test, y_pred_proba)
auc = roc_auc_score(y_test, y_pred_proba)

plt.figure(figsize=(7, 3))