CODEWITHSUNDEEP
pythonmatplotlibplotroc
Amhs_11
Amhs_11

Reputation: 233

ROC curve - the plot does not show as it is expceted

I am trying to plot a ROC curve graph using pyhton matplotlib library. I want to display the curve line as a dish line with a marker as the one showed in the picture below: Figure1 Figure Ref: https://www.biorxiv.org/content/10.1101/2019.12.21.885491v1.full

This is my code:

plt.figure(figsize=(7,7))
fpr, tpr, thresholds = metrics.roc_curve(test_Y, predict_proba)
auc = roc_auc_score(test_Y,y_pred)
plt.plot(fpr, tpr, label='%s (AUC = %0.2f)' % ("LR", auc),marker='h',linestyle='--')
plt.plot([0, 1], [0, 1],'r--',label='No skills')
plt.xlim([-0.02, 1])
plt.ylim([0, 1.02])
plt.xlabel('False Positive Rate (%)')
plt.ylabel('True Positive Rate (%)')
plt.title('ROC Curve')
plt.legend(loc="lower right")
plt.grid()

This is the plot that I have got:

Figure2: my plot

It seems as if something went wrong as the 'marker' printed on the whole line. If I removed the marker parameter from the plot function, I got this:

Figure3

I do not really know why this might happen. Is is something wrong with the way I plotted the graph, or it might be the issue with the model results.

Could anyone please help me out with this.

Upvotes: 0

Views: 1168

Answers (1)

Julien
Julien

Reputation: 15071

Markers are used at every data point passed in. Do you want to plot the whole curve but display markers at only every e.g. 10 points? If so try this:

plt.plot(fpr, tpr, linestyle='--')
plt.plot(fpr[::10], tpr[::10], marker='h')

Upvotes: 2

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