René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"[Bug]: `ax.hist()` fails on sequence of timedeltas due to comparison with `np.inf`","articleBody":"### Bug summary\n\nI expected `ax.hist([sequence of timedeltas])` to Just Work, as it does with `ax.hist([sequence of timestamps])`. However, there is a comparison with `np.inf` that works when the sequence is of timestamps and fails when the sequence is of timedeltas; numpy cannot promote a `TimeDelta64DType` to a float: https://github.com/matplotlib/matplotlib/blob/main/lib/matplotlib/axes/_axes.py#L7479\n\n### Code for reproduction\n\n```Python\nimport matplotlib.pyplot as plt\nimport pandas as pd\nfig = plt.figure(figsize=(10, 7))\nax = fig.add_subplot(1, 1, 1)\nax.hist(pd.date_range(\"2026-01-01\", \"2026-01-05\", freq=\"D\"))\nax.hist(pd.date_range(\"2026-01-01\", \"2026-01-05\", freq=\"D\").diff(1))\n```\n\n### Actual outcome\n\n```\nnumpy.exceptions.DTypePromotionError: The DType \u003cclass 'numpy.dtypes.TimeDelta64DType'\u003e could not be promoted by \u003cclass 'numpy.dtypes._PyFloatDType'\u003e. This means that no common DType exists for the given inputs. For example they cannot be stored in a single array unless the dtype is `object`. The full list of DTypes is: (\u003cclass 'numpy.dtypes.TimeDelta64DType'\u003e, \u003cclass 'numpy.dtypes._PyFloatDType'\u003e)\n\nThe above exception was the direct cause of the following exception:\n\nTraceback (most recent call last):\n  File \"\u003cpython-input-5\u003e\", line 1, in \u003cmodule\u003e\n    ax.hist(pd.date_range(\"2026-01-01\", \"2026-01-05\", freq=\"D\").diff(1))\n    ~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^\n  File \"/Users/kylepenner/Documents/numpy/lib/python3.13/site-packages/matplotlib/_api/deprecation.py\", line 477, in wrapper\n    return func(*args, **kwargs)\n  File \"/Users/kylepenner/Documents/numpy/lib/python3.13/site-packages/matplotlib/__init__.py\", line 1497, in inner\n    return func(\n        ax,\n        *map(cbook.sanitize_sequence, args),\n        **{k: cbook.sanitize_sequence(v) for k, v in kwargs.items()})\n  File \"/Users/kylepenner/Documents/numpy/lib/python3.13/site-packages/matplotlib/axes/_axes.py\", line 7479, in hist\n    xmin = min(xmin, np.nanmin(xi))\nnumpy._core._exceptions._UFuncNoLoopError: ufunc 'less' did not contain a loop with signature matching types (\u003cclass 'numpy.dtypes.TimeDelta64DType'\u003e, \u003cclass 'numpy.dtypes._PyFloatDType'\u003e) -\u003e None\n```\n\n\n### Expected outcome\n\nThere's an easy way around this---convert the timedeltas to floats with `.total_seconds()`---but I do prefer the `hist` call to just work.\n\n### Additional information\n\n_No response_\n\n### Operating system\n\n_No response_\n\n### Matplotlib Version\n\n3.11.0.dev1799+g6dbc0c7cd\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\ngit checkout","author":{"url":"https://github.com/kdpenner","@type":"Person","name":"kdpenner"},"datePublished":"2026-02-20T18:36:25.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":15},"url":"https://github.com/31182/matplotlib/issues/31182"}