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/1326#issuecomment-289519266,https://api.github.com/repos/pydata/xarray/issues/1326,289519266,MDEyOklzc3VlQ29tbWVudDI4OTUxOTI2Ng==,6815844,2017-03-27T17:10:06Z,2017-03-27T17:10:06Z,MEMBER,"OK.
I totally agree with you.

The API now I propose is  

```Python
    def expand_dims(self, dim=None, axis=0):
        """"""Return a new object with an additional axis (or axes) inserted at the
        corresponding position in the array shape.

        Parameters
        ----------
        dim : str, list of strs, tuple of strs, or None
            Name(s) of new dimension.
            If a list (or tuple) of strings is passed, multiple axes are inserted.
            In this case, axis argument should be 0 or same length of integers indicating new axes positions.
        axis : integer, list of integers or tuple of integers
            Axis position(s) where new axis is to be inserted (position(s) on the result array).
            If a list (or tuple) of integers is passed, multiple axes are inserted.
            In this case, dim arguments should be None or same length list. 

        Returns
        -------
        expanded : same type as caller
            This object, but with an additional dimension.
        
        Raises
        -------
        ValueError:
               If the length of axis and dim are different.
               If the axis is a list containing identical integers
               If axis is invalid (larger than the original dimension+1)
```
","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,216799807
https://github.com/pydata/xarray/issues/1326#issuecomment-289511480,https://api.github.com/repos/pydata/xarray/issues/1326,289511480,MDEyOklzc3VlQ29tbWVudDI4OTUxMTQ4MA==,6815844,2017-03-27T16:42:24Z,2017-03-27T16:42:24Z,MEMBER,">I would switch the order of the method arguments.

I agree this.
Do you think it is confusing if this method automatically detects the positional argument, i.e. if string is passed then it should be the axis name and an integer should be axis position.

I think that numpy-like API is most user-friendly, as like TensorFlow imitates them.
I like to support `da.expand_dims(0)` if it is not confusing for users who don't care the axes order.

> We might also consider supporting inserting multiple axes at once

I guess that the reason that numpy doesn't support multiple axes insertion is it brings additional ambugousity to the new axes positions;
e.g.
`da.expand_dims([2,1])` could behave 
```python
da.expand_dims(2)
da.expand_dims(1)
```
or 
```python
da.expand_dims(1)
da.expand_dims(2)
```
the results differ.
(It does not matter if user only specifies the labels or the list is in order.)

I hesitate this option actually. ","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,216799807
https://github.com/pydata/xarray/issues/1326#issuecomment-289210412,https://api.github.com/repos/pydata/xarray/issues/1326,289210412,MDEyOklzc3VlQ29tbWVudDI4OTIxMDQxMg==,6815844,2017-03-25T13:03:41Z,2017-03-25T13:03:41Z,MEMBER,"Yes. How about the following?
(I assume this is a method of `xr.DataArray`.)

```Python
    def expand_dims(self, axis=0, dim=None):
        """"""Return a new object with an additional dimension inserted at the
        corresponding position in the array shape.

        Parameters
        ----------
        axis : integer
            Position (amongst axes) where new axis is to be inserted.
        dim : str or None
            Name of new dimension.

        Returns
        -------
        expanded : same type as caller
            This object, but with an additional dimension.
```

I consider 2 types users; first type users always take care of the dimension order and the other just consider the dimension labels.
The first type users may specify the new axis position as `axis` argument.
The other may just pass the new dimension name regardless of its position,
in which case the new dimension will be appended as the first dimension.

This API is similar to that of `np.expand_dims` and I believe its behavior is intuitive.","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,216799807