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{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Add operator.is_none()","articleBody":"# Feature or enhancement\r\n\r\n### Proposal:\r\n\r\nWith floating point data, the `float('NaN')` special value is commonly used as a placeholder for missing values.  We provide `math.isnan` to support stripping out those values prior to sorting or summation:\r\n\r\n```python\r\n\u003e\u003e\u003e from math import isnan\r\n\u003e\u003e\u003e from itertools import filterfalse\r\n\u003e\u003e\u003e data = [3.3, float('nan'), 1.1, 2.2]\r\n\u003e\u003e\u003e sorted(filterfalse(isnan, data))\r\n[1.1, 2.2, 3.3]\r\n```\r\n\r\nFor non-float data, the `None` special value is commonly used as a placeholder for missing values.  I propose a new function in the operator module analogous to `math.isnan()`:\r\n\r\n```pycon\r\n\u003e\u003e\u003e data = ['c', None, 'a', 'b']\r\n\u003e\u003e\u003e sorted(filterfalse(is_none, data))\r\n['a', 'b', 'c']\r\n```\r\n\r\nThis helps fulfill a primary use case for the operator module which is to support functional programming with `map()`, `filter()`, etc.\r\n\r\n### Has this already been discussed elsewhere?\r\n\r\nNo response given\r\n\r\n### Links to previous discussion of this feature:\r\n\r\n_No response_\n\n\u003c!-- gh-linked-prs --\u003e\n### Linked PRs\n* gh-115814\n\u003c!-- /gh-linked-prs --\u003e\n","author":{"url":"https://github.com/rhettinger","@type":"Person","name":"rhettinger"},"datePublished":"2024-02-22T08:38:25.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":2},"url":"https://github.com/115808/cpython/issues/115808"}