René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"[Bug]: Colorbar get_ticks() return the incorrect array","articleBody":"### Bug summary\n\nWhen creating a colorbar using a ScalarMappable with the NoNorm normalization and a discrete colormap (e.g., viridis with a fixed number of colors), the ticks returned by the colorbar’s get_ticks() method do not align with the visually displayed tick positions. This will cause `cbar.set_ticks(cbar.get_ticks())` to change the ticks.\n\n### Code for reproduction\n\n```Python\nimport matplotlib.pyplot as plt\nfrom matplotlib import cm, colors\ndata = [1, 2, 3, 4, 5]\nfig, ax = plt.subplots()\ncbar = fig.colorbar(cm.ScalarMappable(norm=colors.NoNorm(), cmap=plt.get_cmap(\"viridis\", len(data))), ax=ax)\nprint(cbar.get_ticks())\ncbar.set_ticks(cbar.get_ticks()) # this unexpectedly changes the ticks\n```\n\n### Actual outcome\n\n[0. 1. 2. 3. 4. 5.]\n\n\u003cimg width=\"510\" height=\"418\" alt=\"Image\" src=\"https://github.com/user-attachments/assets/58104102-4fb1-42f9-8438-2fc5a8bf5c60\" /\u003e\n\n### Expected outcome\n\n[0. 1. 2. 3. 4.]\n\n\u003cimg width=\"510\" height=\"418\" alt=\"Image\" src=\"https://github.com/user-attachments/assets/065c9d5f-1813-46ff-a687-543d7b45d14c\" /\u003e\n\n### Additional information\n\n_No response_\n\n### Operating system\n\n_No response_\n\n### Matplotlib Version\n\n3.10.8\n\n### Matplotlib Backend\n\n_No response_\n\n### Python version\n\n_No response_\n\n### Jupyter version\n\n_No response_\n\n### Installation\n\nNone","author":{"url":"https://github.com/williamlus","@type":"Person","name":"williamlus"},"datePublished":"2026-02-05T09:44:50.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":3},"url":"https://github.com/31086/matplotlib/issues/31086"}