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Created on 2022-01-05 16:11 by realjanpaulus, last changed 2022-04-11 14:59 by admin. This issue is now closed.
| Pull Requests | |||
|---|---|---|---|
| URL | Status | Linked | Edit |
| PR 30504 | merged | rhettinger, 2022-01-09 17:03 | |
| PR 30509 | merged | miss-islington, 2022-01-10 02:02 | |
| Messages (7) | |||
|---|---|---|---|
| msg409782 - (view) | Author: Jan (realjanpaulus) | Date: 2022-01-05 16:11 | |
In chapter 5.7 in the official Python tutorial (see: https://docs.python.org/3/tutorial/datastructures.html), there is the following paragraph: "The comparison operators in and not in check whether a value occurs (does not occur) in a sequence. The operators is and is not compare whether two objects are really the same object. All comparison operators have the same priority, which is lower than that of all numerical operators." I believe that "in" and "not in" are rather membership operators than comparison operators. I think a differentiation of operator types in one or two sentences would be helpful. |
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| msg409799 - (view) | Author: Raymond Hettinger (rhettinger) *  |
Date: 2022-01-05 19:14 | |
It may seem weird, but a "membership operator" is a kind of "comparison operator".¹ They can even participate in chaining, 'a < b in s < c` is equivalent to `(a < b) and (b in s) and (b < c)`. I'm propose this new wording to mention the concept of "membership": "The comparison operators `in` and `not in` are membership tests that determine whether a value is in (or not in) a container." ¹ https://docs.python.org/3/reference/expressions.html#comparisons |
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| msg409806 - (view) | Author: Jan (realjanpaulus) | Date: 2022-01-05 21:16 | |
I really like this solution because it mentions the buzz word "membership". But I would change "container" to "sequence" because the term "container" doesn't appear in chapter 5, "sequence" on the other hand multiple times. My proposal: "The comparison operators `in` and `not in` are membership tests that determine whether a value is in (or not in) a sequence." |
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| msg409807 - (view) | Author: Raymond Hettinger (rhettinger) * |
Date: 2022-01-05 21:58 | |
Container is correct. Containers are defined as being anything that supports the "in" and "not in" operators. That includes sequences (str, list, tuple, bytes, bytearray), mappings (dict, ChainMap, defaultdict), and sets (frozenset and set). It doesn't matter that the word container comes up later. At this point in the tutorial we tend to have a number of forward or references. Our tutorial is more a guided walkthrough with examples rather than a series of sequential definitions. |
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| msg409836 - (view) | Author: Jan (realjanpaulus) | Date: 2022-01-06 12:37 | |
Sounds reasonable. |
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| msg410181 - (view) | Author: Raymond Hettinger (rhettinger) * |
Date: 2022-01-10 02:02 | |
New changeset d24cd49acb25c36db31893b84d0ca4fe2f373b94 by Raymond Hettinger in branch 'main': bpo-46270: Describe the `in` and `not in` operators as membership tests. (GH-30504) https://github.com/python/cpython/commit/d24cd49acb25c36db31893b84d0ca4fe2f373b94 |
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| msg410182 - (view) | Author: Raymond Hettinger (rhettinger) * |
Date: 2022-01-10 02:32 | |
New changeset 2e6798f35260ff90129861ef1f289ac40c0396c2 by Miss Islington (bot) in branch '3.10': bpo-46270: Describe the `in` and `not in` operators as membership tests. (GH-30504) (GH-30509) https://github.com/python/cpython/commit/2e6798f35260ff90129861ef1f289ac40c0396c2 |
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| History | |||
|---|---|---|---|
| Date | User | Action | Args |
| 2022-04-11 14:59:54 | admin | set | github: 90428 |
| 2022-01-10 02:32:01 | rhettinger | set | messages: + msg410182 |
| 2022-01-10 02:03:13 | rhettinger | set | status: open -> closed stage: patch review -> resolved |
| 2022-01-10 02:02:28 | miss-islington | set | nosy:
+ miss-islington pull_requests: + pull_request28713 |
| 2022-01-10 02:02:14 | rhettinger | set | messages: + msg410181 |
| 2022-01-09 17:03:17 | rhettinger | set | keywords:
+ patch stage: patch review pull_requests: + pull_request28709 |
| 2022-01-06 12:37:05 | realjanpaulus | set | resolution: works for me -> fixed messages: + msg409836 |
| 2022-01-05 21:58:37 | rhettinger | set | messages: + msg409807 |
| 2022-01-05 21:16:57 | realjanpaulus | set | resolution: works for me messages: + msg409806 |
| 2022-01-05 19:14:42 | rhettinger | set | messages: + msg409799 |
| 2022-01-05 18:31:17 | rhettinger | set | assignee: docs@python -> rhettinger nosy: + rhettinger |
| 2022-01-05 16:11:18 | realjanpaulus | create | |