html_url,issue_url,id,node_id,user,created_at,updated_at,author_association,body,reactions,performed_via_github_app,issue
https://github.com/pydata/xarray/issues/1251#issuecomment-1111431038,https://api.github.com/repos/pydata/xarray/issues/1251,1111431038,IC_kwDOAMm_X85CPxd-,5635139,2022-04-27T20:06:24Z,2022-04-27T20:06:24Z,MEMBER,"FYI the `apply` / `map` change went in a couple of years ago.

We still don't have an `apply_raw`. I think it probably makes sense to consolidate this with https://github.com/pydata/xarray/issues/1618, so I'll close this, even though it has some good discussion.","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,205455788
https://github.com/pydata/xarray/issues/1251#issuecomment-550046990,https://api.github.com/repos/pydata/xarray/issues/1251,550046990,MDEyOklzc3VlQ29tbWVudDU1MDA0Njk5MA==,2448579,2019-11-05T22:14:49Z,2019-11-05T22:14:49Z,MEMBER,@max-sixty I like your proposal!,"{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,205455788
https://github.com/pydata/xarray/issues/1251#issuecomment-550037494,https://api.github.com/repos/pydata/xarray/issues/1251,550037494,MDEyOklzc3VlQ29tbWVudDU1MDAzNzQ5NA==,1217238,2019-11-05T21:50:01Z,2019-11-05T21:50:01Z,MEMBER,"> I more strongly think that `apply` is a confusing and non-standard term for ""run this function on _each item_ in this container"", even if it's pandas' name.

This is a fair point. `map` is definitely the standard name in the context of ""map reduce"" type operations.

> What are your thoughts re:
> 
> * Adding `map` as the documented approach for run-on-each on `Dataset` & `GroupBy`
> * Adding `apply_raw` (or similar) as a new function that runs functions on the 'raw' arrays
> * Keeping `apply` around for backward-compat, similar to the `drop` case

I would support this.","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,205455788
https://github.com/pydata/xarray/issues/1251#issuecomment-550035303,https://api.github.com/repos/pydata/xarray/issues/1251,550035303,MDEyOklzc3VlQ29tbWVudDU1MDAzNTMwMw==,5635139,2019-11-05T21:44:44Z,2019-11-05T21:44:44Z,MEMBER,"OK. Does that inform your view on `map` vs `apply`? 

I more strongly think that `apply` is a confusing and non-standard term for ""run this function on _each item_ in this container"", even if it's pandas' name.

I'm keener to offer `map` an as option that necessarily reusing `apply`. 

What are your thoughts re:
- Adding `map` as the documented approach for run-on-each on `Dataset` & `GroupBy`
- Adding `apply_raw` (or similar) as a new function that runs functions on the 'raw' arrays
- Keeping `apply` around for backward-compat, similar to the `drop` case","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,205455788
https://github.com/pydata/xarray/issues/1251#issuecomment-549627167,https://api.github.com/repos/pydata/xarray/issues/1251,549627167,MDEyOklzc3VlQ29tbWVudDU0OTYyNzE2Nw==,1217238,2019-11-05T01:48:30Z,2019-11-05T01:48:30Z,MEMBER,"+@dcherian 

@max-sixty thanks for pushing this along!

I think I'm coming to appreciate backwards compatibility as an important consideration more and more these days. It's just really painful to reuse methods for something entirely different.

This makes me lean towards adding separate `apply_raw()` methods. The name is definitely less memorable than `apply`, but on the other hand it is also definitely easier to guess the difference between `apply`/`apply_raw` then `apply`/`map`.","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,205455788
https://github.com/pydata/xarray/issues/1251#issuecomment-547592571,https://api.github.com/repos/pydata/xarray/issues/1251,547592571,MDEyOklzc3VlQ29tbWVudDU0NzU5MjU3MQ==,5635139,2019-10-29T19:32:14Z,2019-10-30T00:22:56Z,MEMBER,"I put the change for `Dataset.apply` -> `Dataset.map` in. Should we do the same for `GroupBy`? 

I think those are probably the two easiest decisions to make (and hopefully will kick off moving this issue forwards)

Edit: the reason I hesitated for `GroupBy` is that it's not exactly the same: the object returned isn't the same (i.e. `Dataset.map` returns a `Dataset`, while `GroupBy.map` would return a `Dataset`)","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,205455788
https://github.com/pydata/xarray/issues/1251#issuecomment-456195815,https://api.github.com/repos/pydata/xarray/issues/1251,456195815,MDEyOklzc3VlQ29tbWVudDQ1NjE5NTgxNQ==,1217238,2019-01-21T20:52:07Z,2019-01-21T20:52:07Z,MEMBER,"I don't think we should consider ourselves beholden to pandas's bad names, but we should definitely try to preserve backwards compatibility and interpretability for users.

Going back to Python itself:
- `apply(func, args, kwargs)` (from Python 2.x) is equivalent to `func(*args, **kwargs)`
- `map()` maps a function over each element of an iterable
- `functools.reduce()` applies a binary function repeatedly to convert an iterable into a single element

For xarray, we need:
1. a method for wrapping functions that work on unlabeled arrays
2. a method for mapping functions over each element of a Dataset or grouped object.
3. (possibly) a method for wrapping aggregation functions that act on unlabeled arrays

Currently, we call both (1) and (2) `apply()`, which is pretty confusing, and use `reduce()` for (3) even though it could potentially be a special case of (1) with a bit of extra magic and is quite unlike `functools.reduce`. In contrast, pandas calls both (1) and (2) `apply()` (using `raw=True`/`raw=False` to distinguish), and  calls (3) `aggregate` or `agg`.

So long term, it could make sense to rename the current `Dataset.apply()`/`GroupBy.apply()` (case 2) to `.map`, and also rename `.reduce()` to the more generic `.aggregate()`.

That said, I'm trying to imagine what the transition process for switching to new behavior for `Dataset.apply` looks like. We already will re-add dimensions to the output from calling functions in `apply()`, but at some point we have to a do a hard cut-off from passing `DataArray` objects to the function in `apply` to passing in a raw array.

I suppose we could do this by adding a `raw` keyword-only argument to `.apply()`:
- If `raw=False` (current default), we would raise a warning about changing behavior and would pass-on `DataArray` objects to the applied function. Users would be encouraged to use `.map()` instead.
- If `raw=True` (future default behavior), we would pass in raw numpy/dask arrays to the future function.
- The `dim` argument might only be supported with `raw=True`.

We would end up with an extra extraneous `raw` argument, which we could remove/deprecate at our leisure.","{""total_count"": 3, ""+1"": 3, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,205455788
https://github.com/pydata/xarray/issues/1251#issuecomment-455353612,https://api.github.com/repos/pydata/xarray/issues/1251,455353612,MDEyOklzc3VlQ29tbWVudDQ1NTM1MzYxMg==,5635139,2019-01-17T22:21:06Z,2019-01-17T22:21:06Z,MEMBER,"> I would like to rename rolling.reduce to rolling.apply to be consistent with pandas & groupby

+0.5 if `map` fails","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,205455788
https://github.com/pydata/xarray/issues/1251#issuecomment-455350875,https://api.github.com/repos/pydata/xarray/issues/1251,455350875,MDEyOklzc3VlQ29tbWVudDQ1NTM1MDg3NQ==,2448579,2019-01-17T22:10:44Z,2019-01-17T22:10:44Z,MEMBER,"> One proposal: rename apply to map

-1 for pandas incompatibility.

I would like to rename `rolling.reduce` to `rolling.apply` to be consistent with pandas & groupby","{""total_count"": 1, ""+1"": 1, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,205455788
https://github.com/pydata/xarray/issues/1251#issuecomment-455349535,https://api.github.com/repos/pydata/xarray/issues/1251,455349535,MDEyOklzc3VlQ29tbWVudDQ1NTM0OTUzNQ==,5635139,2019-01-17T22:06:05Z,2019-01-17T22:06:05Z,MEMBER,"> One proposal: rename apply to map

Would we accept this? I'd be up for doing the PR to deprecate `apply` and introduce `map`. It makes a Dataset more consistent with a standard mapping interface. But it would be inconsistent with pandas and a rename of fairly widely used method","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,205455788
https://github.com/pydata/xarray/issues/1251#issuecomment-277942376,https://api.github.com/repos/pydata/xarray/issues/1251,277942376,MDEyOklzc3VlQ29tbWVudDI3Nzk0MjM3Ng==,4160723,2017-02-07T09:16:34Z,2017-02-07T09:16:34Z,MEMBER,I would be +1 for `apply` and `apply_raw`.,"{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,205455788
https://github.com/pydata/xarray/issues/1251#issuecomment-277888535,https://api.github.com/repos/pydata/xarray/issues/1251,277888535,MDEyOklzc3VlQ29tbWVudDI3Nzg4ODUzNQ==,1217238,2017-02-07T03:08:41Z,2017-02-07T03:08:41Z,MEMBER,"Another option is to keep `apply` as-is for Dataset and GroupBy objects, but add a separate `apply_raw` method for applying functions that act on ""raw"" arrays. This would be a little more similar to pandas' `apply` with `raw=True`.

We could even do the `raw=True` keyword argument like pandas, but this is a little awkward because there are some additional arguments on `apply_raw` that don't make sense on `apply` (e.g., arguments that specify that some dimensions should be dropped or added).","{""total_count"": 2, ""+1"": 2, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,205455788
https://github.com/pydata/xarray/issues/1251#issuecomment-277576392,https://api.github.com/repos/pydata/xarray/issues/1251,277576392,MDEyOklzc3VlQ29tbWVudDI3NzU3NjM5Mg==,5635139,2017-02-06T03:01:06Z,2017-02-06T03:01:06Z,MEMBER,"Sounds good. It breaks the consistency with pandas' `apply`, but `map` is much more logical","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,205455788