Rename combine functions (#3043)

* Renamed combine functions in code

* Renamed combine functions in docs

* pep8 fixes

* Fixed mistake in docstring

* Removed trailing whitespace in error messages

doc/api.rst

@@ -20,8 +20,8 @@ Top-level functions
    concat
    merge
    auto_combine
-   combine_auto
-   combine_manual
+   combine_by_coords
+   combine_nested
    where
    set_options
    full_like

doc/combining.rst

@@ -247,23 +247,23 @@ Combining along multiple dimensions
 .. note::
 
   There are currently three combining functions with similar names:
-  :py:func:`~xarray.auto_combine`, :py:func:`~xarray.combine_auto`, and
-  :py:func:`~xarray.combine_manual`. This is because
+  :py:func:`~xarray.auto_combine`, :py:func:`~xarray.combine_by_coords`, and
+  :py:func:`~xarray.combine_nested`. This is because
   ``auto_combine`` is in the process of being deprecated in favour of the other
   two functions, which are more general. If your code currently relies on
   ``auto_combine``, then you will be able to get similar functionality by using
-  ``combine_manual``.
+  ``combine_nested``.
 
 For combining many objects along multiple dimensions xarray provides
-:py:func:`~xarray.combine_manual`` and :py:func:`~xarray.combine_auto`. These
+:py:func:`~xarray.combine_nested`` and :py:func:`~xarray.combine_by_coords`. These
 functions use a combination of ``concat`` and ``merge`` across different
 variables to combine many objects into one.
 
-:py:func:`~xarray.combine_manual`` requires specifying the order in which the
-objects should be combined, while :py:func:`~xarray.combine_auto` attempts to
+:py:func:`~xarray.combine_nested`` requires specifying the order in which the
+objects should be combined, while :py:func:`~xarray.combine_by_coords` attempts to
 infer this ordering automatically from the coordinates in the data.
 
-:py:func:`~xarray.combine_manual` is useful when you know the spatial
+:py:func:`~xarray.combine_nested` is useful when you know the spatial
 relationship between each object in advance. The datasets must be provided in
 the form of a nested list, which specifies their relative position and
 ordering. A common task is collecting data from a parallelized simulation where
@@ -276,9 +276,9 @@ datasets into a doubly-nested list, e.g:
     arr = xr.DataArray(name='temperature', data=np.random.randint(5, size=(2, 2)), dims=['x', 'y'])
     arr
     ds_grid = [[arr, arr], [arr, arr]]
-    xr.combine_manual(ds_grid, concat_dim=['x', 'y'])
+    xr.combine_nested(ds_grid, concat_dim=['x', 'y'])
 
-:py:func:`~xarray.combine_manual` can also be used to explicitly merge datasets
+:py:func:`~xarray.combine_nested` can also be used to explicitly merge datasets
 with different variables. For example if we have 4 datasets, which are divided
 along two times, and contain two different variables, we can pass ``None``
 to ``'concat_dim'`` to specify the dimension of the nested list over which
@@ -289,25 +289,25 @@ we wish to use ``merge`` instead of ``concat``:
     temp = xr.DataArray(name='temperature', data=np.random.randn(2), dims=['t'])
     precip = xr.DataArray(name='precipitation', data=np.random.randn(2), dims=['t'])
     ds_grid = [[temp, precip], [temp, precip]]
-    xr.combine_manual(ds_grid, concat_dim=['t', None])
+    xr.combine_nested(ds_grid, concat_dim=['t', None])
 
-:py:func:`~xarray.combine_auto` is for combining objects which have dimension
+:py:func:`~xarray.combine_by_coords` is for combining objects which have dimension
 coordinates which specify their relationship to and order relative to one
 another, for example a linearly-increasing 'time' dimension coordinate.
 
 Here we combine two datasets using their common dimension coordinates. Notice
 they are concatenated in order based on the values in their dimension
-coordinates, not on their position in the list passed to ``combine_auto``.
+coordinates, not on their position in the list passed to ``combine_by_coords``.
 
 .. ipython:: python
     :okwarning:
 
     x1 = xr.DataArray(name='foo', data=np.random.randn(3), coords=[('x', [0, 1, 2])])
     x2 = xr.DataArray(name='foo', data=np.random.randn(3), coords=[('x', [3, 4, 5])])
-    xr.combine_auto([x2, x1])
+    xr.combine_by_coords([x2, x1])
 
 These functions can be used by :py:func:`~xarray.open_mfdataset` to open many
 files as one dataset. The particular function used is specified by setting the
-argument ``'combine'`` to ``'auto'`` or ``'manual'``. This is useful for
+argument ``'combine'`` to ``'by_coords'`` or ``'nested'``. This is useful for
 situations where your data is split across many files in multiple locations,
 which have some known relationship between one another.

doc/computation.rst

@@ -160,7 +160,7 @@ object:
 
 Aggregation results are assigned the coordinate at the end of each window by
 default, but can be centered by passing ``center=True`` when constructing the
- ``Rolling`` object:
+``Rolling`` object:
 
 .. ipython:: python
 

doc/io.rst

@@ -767,8 +767,8 @@ Combining multiple files
 NetCDF files are often encountered in collections, e.g., with different files
 corresponding to different model runs. xarray can straightforwardly combine such
 files into a single Dataset by making use of :py:func:`~xarray.concat`,
-:py:func:`~xarray.merge`, :py:func:`~xarray.combine_manual` and
-:py:func:`~xarray.combine_auto`. For details on the difference between these
+:py:func:`~xarray.merge`, :py:func:`~xarray.combine_nested` and
+:py:func:`~xarray.combine_by_coords`. For details on the difference between these
 functions see :ref:`combining data`.
 
 .. note::

doc/whats-new.rst

@@ -60,17 +60,17 @@ Enhancements
   Datasets can now be combined along any number of dimensions,
   instead of just a one-dimensional list of datasets.
 
-  The new ``combine_manual`` will accept the datasets as a a nested
+  The new ``combine_nested`` will accept the datasets as a a nested
   list-of-lists, and combine by applying a series of concat and merge
-  operations. The new ``combine_auto`` will instead use the dimension
+  operations. The new ``combine_by_coords`` will instead use the dimension
   coordinates of the datasets to order them.
 
-  ``open_mfdataset`` can use either ``combine_manual`` or ``combine_auto`` to
+  ``open_mfdataset`` can use either ``combine_nested`` or ``combine_by_coords`` to
   combine datasets along multiple dimensions, by specifying the argument
-  `combine='manual'` or `combine='auto'`.
+  `combine='nested'` or `combine='by_coords'`.
 
   This means that the original function ``auto_combine`` is being deprecated.
-  To avoid FutureWarnings switch to using `combine_manual` or `combine_auto`,
+  To avoid FutureWarnings switch to using `combine_nested` or `combine_by_coords`,
   (or set the `combine` argument in `open_mfdataset`). (:issue:`2159`)
   By `Tom Nicholas <http://github.com/TomNicholas>`_.
 - Better warning message when supplying invalid objects to ``xr.merge``

xarray/__init__.py

@@ -8,7 +8,7 @@
 from .core.alignment import align, broadcast, broadcast_arrays
 from .core.common import full_like, zeros_like, ones_like
 from .core.concat import concat
-from .core.combine import combine_auto, combine_manual, auto_combine
+from .core.combine import combine_by_coords, combine_nested, auto_combine
 from .core.computation import apply_ufunc, dot, where
 from .core.extensions import (register_dataarray_accessor,
                               register_dataset_accessor)

xarray/backends/api.py

@@ -10,7 +10,7 @@
 from .. import Dataset, DataArray, backends, conventions
 from ..core import indexing
 from .. import auto_combine
-from ..core.combine import (combine_auto, _manual_combine,
+from ..core.combine import (combine_by_coords, _nested_combine,
                             _infer_concat_order_from_positions)
 from ..core.utils import close_on_error, is_grib_path, is_remote_uri
 from .common import ArrayWriter
@@ -599,15 +599,16 @@ def open_mfdataset(paths, chunks=None, concat_dim='_not_supplied',
                    **kwargs):
     """Open multiple files as a single dataset.
 
-    If combine='auto' then the function `combine_auto` is used to combine the
-    datasets into one before returning the result, and if combine='manual' then
-    `combine_manual` is used. The filepaths must be structured according to
-    which combining function is used, the details of which are given in the
-    documentation for ``combine_auto`` and ``combine_manual``.
-    By default the old (now deprecated) ``auto_combine`` will be used, please 
-    specify either ``combine='auto'`` or ``combine='manual'`` in future.
-    Requires dask to be installed. See documentation for details on dask [1].
-    Attributes from the first dataset file are used for the combined dataset.
+    If combine='by_coords' then the function ``combine_by_coords`` is used to 
+    combine the datasets into one before returning the result, and if 
+    combine='nested' then ``combine_nested`` is used. The filepaths must be 
+    structured according to which combining function is used, the details of 
+    which are given in the documentation for ``combine_by_coords`` and 
+    ``combine_nested``. By default the old (now deprecated) ``auto_combine`` 
+    will be used, please specify either ``combine='by_coords'`` or 
+    ``combine='nested'`` in future. Requires dask to be installed. See 
+    documentation for details on dask [1]. Attributes from the first dataset 
+    file are used for the combined dataset.
 
     Parameters
     ----------
@@ -631,11 +632,11 @@ def open_mfdataset(paths, chunks=None, concat_dim='_not_supplied',
         if you want to stack a collection of 2D arrays along a third dimension.
         Set ``concat_dim=[..., None, ...]`` explicitly to
         disable concatenation along a particular dimension.
-    combine : {'auto', 'manual'}, optional
-        Whether ``xarray.auto_combine`` or ``xarray.manual_combine`` is used to
-        combine all the data. If this argument is not provided, 
+    combine : {'by_coords', 'nested'}, optional
+        Whether ``xarray.combine_by_coords`` or ``xarray.combine_nested`` is 
+        used to combine all the data. If this argument is not provided, 
         `xarray.auto_combine` is used, but in the future this behavior will 
-        switch to use `xarray.combine_auto`.
+        switch to use `xarray.combine_by_coords` by default.
     compat : {'identical', 'equals', 'broadcast_equals',
               'no_conflicts'}, optional
         String indicating how to compare variables of the same name for
@@ -706,8 +707,8 @@ def open_mfdataset(paths, chunks=None, concat_dim='_not_supplied',
 
     See Also
     --------
-    combine_auto
-    combine_manual
+    combine_by_coords
+    combine_nested
     auto_combine
     open_dataset
 
@@ -730,13 +731,13 @@ def open_mfdataset(paths, chunks=None, concat_dim='_not_supplied',
     if not paths:
         raise IOError('no files to open')
 
-    # If combine='auto' then this is unnecessary, but quick.
-    # If combine='manual' then this creates a flat list which is easier to
+    # If combine='by_coords' then this is unnecessary, but quick.
+    # If combine='nested' then this creates a flat list which is easier to
     # iterate over, while saving the originally-supplied structure as "ids"
-    if combine == 'manual':
+    if combine == 'nested':
         if str(concat_dim) == '_not_supplied':
             raise ValueError("Must supply concat_dim when using "
-                             "combine='manual'")
+                             "combine='nested'")
         else:
             if isinstance(concat_dim, (str, DataArray)) or concat_dim is None:
                 concat_dim = [concat_dim]
@@ -776,17 +777,17 @@ def open_mfdataset(paths, chunks=None, concat_dim='_not_supplied',
             combined = auto_combine(datasets, concat_dim=concat_dim,
                                     compat=compat, data_vars=data_vars,
                                     coords=coords)
-        elif combine == 'manual':
+        elif combine == 'nested':
             # Combined nested list by successive concat and merge operations
             # along each dimension, using structure given by "ids"
-            combined = _manual_combine(datasets, concat_dims=concat_dim,
+            combined = _nested_combine(datasets, concat_dims=concat_dim,
                                        compat=compat, data_vars=data_vars,
                                        coords=coords, ids=ids)
-        elif combine == 'auto':
+        elif combine == 'by_coords':
             # Redo ordering from coordinates, ignoring how they were ordered
             # previously
-            combined = combine_auto(datasets, compat=compat,
-                                    data_vars=data_vars, coords=coords)
+            combined = combine_by_coords(datasets, compat=compat,
+                                         data_vars=data_vars, coords=coords)
         else:
             raise ValueError("{} is an invalid option for the keyword argument"
                              " ``combine``".format(combine))

xarray/core/combine.py

@@ -216,8 +216,8 @@ def _combine_1d(datasets, concat_dim, compat='no_conflicts', data_vars='all',
         except ValueError as err:
             if "encountered unexpected variable" in str(err):
                 raise ValueError("These objects cannot be combined using only "
-                                 "xarray.combine_manual, instead either use "
-                                 "xarray.combine_auto, or do it manually "
+                                 "xarray.combine_nested, instead either use "
+                                 "xarray.combine_by_coords, or do it manually "
                                  "with xarray.concat, xarray.merge and "
                                  "xarray.align")
             else:
@@ -233,7 +233,7 @@ def _new_tile_id(single_id_ds_pair):
     return tile_id[1:]
 
 
-def _manual_combine(datasets, concat_dims, compat, data_vars, coords, ids,
+def _nested_combine(datasets, concat_dims, compat, data_vars, coords, ids,
                     fill_value=dtypes.NA):
 
     if len(datasets) == 0:
@@ -259,7 +259,7 @@ def _manual_combine(datasets, concat_dims, compat, data_vars, coords, ids,
     return combined
 
 
-def combine_manual(datasets, concat_dim, compat='no_conflicts',
+def combine_nested(datasets, concat_dim, compat='no_conflicts',
                    data_vars='all', coords='different', fill_value=dtypes.NA):
     """
     Explicitly combine an N-dimensional grid of datasets into one by using a
@@ -335,7 +335,7 @@ def combine_manual(datasets, concat_dim, compat='no_conflicts',
       precipitation     (x, y) float64 5.904 2.453 3.404 ...
 
     >>> ds_grid = [[x1y1, x1y2], [x2y1, x2y2]]
-    >>> combined = xr.combine_manual(ds_grid, concat_dim=['x', 'y'])
+    >>> combined = xr.combine_nested(ds_grid, concat_dim=['x', 'y'])
     <xarray.Dataset>
     Dimensions:         (x: 4, y: 4)
     Dimensions without coordinates: x, y
@@ -364,7 +364,7 @@ def combine_manual(datasets, concat_dim, compat='no_conflicts',
       precipitation     (t) float64 5.904 2.453 3.404 ...
 
     >>> ds_grid = [[t1temp, t1precip], [t2temp, t2precip]]
-    >>> combined = xr.combine_manual(ds_grid, concat_dim=['t', None])
+    >>> combined = xr.combine_nested(ds_grid, concat_dim=['t', None])
     <xarray.Dataset>
     Dimensions:         (t: 10)
     Dimensions without coordinates: t
@@ -382,7 +382,7 @@ def combine_manual(datasets, concat_dim, compat='no_conflicts',
         concat_dim = [concat_dim]
 
     # The IDs argument tells _manual_combine that datasets aren't yet sorted
-    return _manual_combine(datasets, concat_dims=concat_dim, compat=compat,
+    return _nested_combine(datasets, concat_dims=concat_dim, compat=compat,
                            data_vars=data_vars, coords=coords, ids=False,
                            fill_value=fill_value)
 
@@ -391,8 +391,8 @@ def vars_as_keys(ds):
     return tuple(sorted(ds))
 
 
-def combine_auto(datasets, compat='no_conflicts', data_vars='all',
-                 coords='different', fill_value=dtypes.NA):
+def combine_by_coords(datasets, compat='no_conflicts', data_vars='all',
+                      coords='different', fill_value=dtypes.NA):
     """
     Attempt to auto-magically combine the given datasets into one by using
     dimension coordinates.
@@ -449,14 +449,14 @@ def combine_auto(datasets, compat='no_conflicts', data_vars='all',
     --------
     concat
     merge
-    combine_manual
+    combine_nested
 
     Examples
     --------
 
     Combining two datasets using their common dimension coordinates. Notice
     they are concatenated based on the values in their dimension coordinates,
-    not on their position in the list passed to `combine_auto`.
+    not on their position in the list passed to `combine_by_coords`.
 
     >>> x1
     <xarray.Dataset>
@@ -474,7 +474,7 @@ def combine_auto(datasets, compat='no_conflicts', data_vars='all',
     Data variables:
         temperature     (x) float64 6.97 8.13 7.42 ...
 
-    >>> combined = xr.combine_auto([x2, x1])
+    >>> combined = xr.combine_by_coords([x2, x1])
     <xarray.Dataset>
     Dimensions:         (x: 6)
     Coords:
@@ -528,8 +528,8 @@ def auto_combine(datasets, concat_dim='_not_supplied', compat='no_conflicts',
     """
     Attempt to auto-magically combine the given datasets into one.
 
-    This entire function is deprecated in favour of ``combine_manual`` and
-    ``combine_auto``.
+    This entire function is deprecated in favour of ``combine_nested`` and
+    ``combine_by_coords``.
 
     This method attempts to combine a list of datasets into a single entity by
     inspecting metadata and using a combination of concat and merge.
@@ -593,34 +593,35 @@ def auto_combine(datasets, concat_dim='_not_supplied', compat='no_conflicts',
         message = dedent("""\
         Also `open_mfdataset` will no longer accept a `concat_dim` argument.
         To get equivalent behaviour from now on please use the new
-        `combine_manual` function instead (or the `combine='manual'` option to
+        `combine_nested` function instead (or the `combine='nested'` option to
         `open_mfdataset`).""")
 
     if _dimension_coords_exist(datasets):
         message += dedent("""\
         The datasets supplied have global dimension coordinates. You may want
-        to use the new `combine_auto` function (or the `combine='auto'` option
-        to `open_mfdataset` to order the datasets before concatenation.
-        Alternatively, to continue concatenating based on the order the
-        datasets are supplied in in future, please use the new `combine_manual`
-        function (or the `combine='manual'` option to open_mfdataset).""")
+        to use the new `combine_by_coords` function (or the
+        `combine='by_coords'` option to `open_mfdataset` to order the datasets
+        before concatenation. Alternatively, to continue concatenating based
+        on the order the datasets are supplied in in future, please use the
+        new `combine_nested` function (or the `combine='nested'` option to
+        open_mfdataset).""")
     else:
         message += dedent("""\
         The datasets supplied do not have global dimension coordinates. In
         future, to continue concatenating without supplying dimension
-        coordinates, please use the new `combine_manual` function (or the
-        `combine='manual'` option to open_mfdataset.""")
+        coordinates, please use the new `combine_nested` function (or the
+        `combine='nested'` option to open_mfdataset.""")
 
     if _requires_concat_and_merge(datasets):
         manual_dims = [concat_dim].append(None)
         message += dedent("""\
         The datasets supplied require both concatenation and merging. From
         xarray version 0.14 this will operation will require either using the
-        new `combine_manual` function (or the `combine='manual'` option to
+        new `combine_nested` function (or the `combine='nested'` option to
         open_mfdataset), with a nested list structure such that you can combine
         along the dimensions {}. Alternatively if your datasets have global
-        dimension coordinates then you can use the new `combine_auto` function.
-        """.format(manual_dims))
+        dimension coordinates then you can use the new `combine_by_coords`
+        function.""".format(manual_dims))
 
     warnings.warn(message, FutureWarning, stacklevel=2)