René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"[MNT]: Discussion : Normalize hatch patterns per dataset instead of per patch in grouped_bar","articleBody":"### Summary\n\nThe current implementation cycles hatch patterns per patch, which breaks grouped bar semantics because each dataset produces multiple patches. This causes hatch patterns to repeat incorrectly within a dataset.\n\n### Proposed fix\n\nReplace the patch-level hatch cycling with dataset-level normalization.\nSpecifically:\nDetermine the number of datasets (num_datasets = len(heights)),\nNormalize hatch to one pattern per dataset,\nApply that hatch consistently to all patches belonging to the same dataset.\nThis aligns hatch behavior with existing color/label broadcasting in grouped_bar and resolves the test failures caused by per-patch cycling.\n\n```\n# Normalize hatches: one hatch per dataset (no per-patch cycling)\nnum_datasets = len(heights)\nuser_hatch = kwargs.get(\"hatch\", None)\n\nif user_hatch is None:\n    # No hatch specified → all datasets get None\n    hatches = [None] * num_datasets\nelse:\n    # Ensure list-like\n    if isinstance(user_hatch, str):\n        raise TypeError(\"hatch must be a list-like of strings, not a single string\")\n\n    try:\n        hatch_list = list(user_hatch)\n    except TypeError:\n        raise TypeError(\"hatch must be list-like\")\n\n    if len(hatch_list) \u003c num_datasets:\n        raise ValueError(\n            f\"Expected at least {num_datasets} hatch patterns for {num_datasets} datasets\"\n        )\n\n    # Use exactly one hatch per dataset\n    hatches = hatch_list[:num_datasets]\n\n# Iterator used by the bar-creation loop\nhatches = iter(hatches)\n```\n","author":{"url":"https://github.com/ilakkmanoharan","@type":"Person","name":"ilakkmanoharan"},"datePublished":"2025-11-25T13:25:25.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":2},"url":"https://github.com/30789/matplotlib/issues/30789"}