Tracking issue for cmp::{min_by, min_by_key, max_by, max_by_key}
#64460
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B-unstable
Blocker: Implemented in the nightly compiler and unstable.
C-tracking-issue
Category: A tracking issue for an RFC or an unstable feature.
Libs-Tracked
Libs issues that are tracked on the team's project board.
T-libs-api
Relevant to the library API team, which will review and decide on the PR/issue.
Comments
jonas-schievink
added
B-unstable
tmandry
added a commit
to tmandry/rust
that referenced
this issue
Sep 20, 2019
Add `cmp::{min_by, min_by_key, max_by, max_by_key}`
This adds the following functions to `core::cmp`:
- `min_by`
- `min_by_key`
- `max_by`
- `max_by_key`
`min_by` and `max_by` are somewhat trivial to implement, but not entirely because `min_by` returns the first value in case the two are equal (and `max_by` the second). `min` and `max` can be implemented in terms of `min_by` and `max_by`, but not as easily the other way around.
To give an example of why I think these functions could be useful: the `Iterator::{min_by, min_by_key, max_by, max_by_key}` methods all currently hard-code the behavior mentioned above which is an ever so small duplication of logic. If we delegate them to `cmp::{min_by, max_by}` methods instead, we get the correct behavior for free. (edit: this is now included in the PR)
I added `min_by_key` / `max_by_key` for consistency's sake but I wouldn't mind removing them. I don't have a particular use case in mind for them, and `min_by` / `max_by` seem to be more useful.
Tracking issue: rust-lang#64460
tmandry
added a commit
to tmandry/rust
that referenced
this issue
Sep 21, 2019
Add `cmp::{min_by, min_by_key, max_by, max_by_key}`
This adds the following functions to `core::cmp`:
- `min_by`
- `min_by_key`
- `max_by`
- `max_by_key`
`min_by` and `max_by` are somewhat trivial to implement, but not entirely because `min_by` returns the first value in case the two are equal (and `max_by` the second). `min` and `max` can be implemented in terms of `min_by` and `max_by`, but not as easily the other way around.
To give an example of why I think these functions could be useful: the `Iterator::{min_by, min_by_key, max_by, max_by_key}` methods all currently hard-code the behavior mentioned above which is an ever so small duplication of logic. If we delegate them to `cmp::{min_by, max_by}` methods instead, we get the correct behavior for free. (edit: this is now included in the PR)
I added `min_by_key` / `max_by_key` for consistency's sake but I wouldn't mind removing them. I don't have a particular use case in mind for them, and `min_by` / `max_by` seem to be more useful.
Tracking issue: rust-lang#64460
bors
added a commit
that referenced
this issue
Sep 21, 2019
Add `cmp::{min_by, min_by_key, max_by, max_by_key}`
This adds the following functions to `core::cmp`:
- `min_by`
- `min_by_key`
- `max_by`
- `max_by_key`
`min_by` and `max_by` are somewhat trivial to implement, but not entirely because `min_by` returns the first value in case the two are equal (and `max_by` the second). `min` and `max` can be implemented in terms of `min_by` and `max_by`, but not as easily the other way around.
To give an example of why I think these functions could be useful: the `Iterator::{min_by, min_by_key, max_by, max_by_key}` methods all currently hard-code the behavior mentioned above which is an ever so small duplication of logic. If we delegate them to `cmp::{min_by, max_by}` methods instead, we get the correct behavior for free. (edit: this is now included in the PR)
I added `min_by_key` / `max_by_key` for consistency's sake but I wouldn't mind removing them. I don't have a particular use case in mind for them, and `min_by` / `max_by` seem to be more useful.
Tracking issue: #64460
|
Is there anything blocking this from stabilizing? |
KodrAus
added
I-nominated
Libs-Tracked
|
Doesn't look like it! If somebody would like to open a stabilization PR then we can start a FCP 🙂 |
|
Stabilization PR up at #81047 |
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Tracking issue for the
cmp_min_max_byfeature, which adds themin_by/min_by_key/max_by/max_by_keyfunctions tostd::cmp.PR: #64047
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