Add how do I ... section (#3357)

* Add how do I ... section

* Bbugfix.

* Update doc/howdoi.rst

Co-Authored-By: Maximilian Roos <5635139+max-sixty@users.noreply.github.com>

* Update doc/howdoi.rst

Co-Authored-By: Maximilian Roos <5635139+max-sixty@users.noreply.github.com>

* small updates.

* Add more.

doc/_static/style.css

@@ -16,3 +16,12 @@
 .wy-nav-top {
   background-color: #555;
 }
+
+table.colwidths-given {
+    table-layout: fixed;
+    width: 100%;
+}
+table.docutils td {
+    white-space: unset;
+    word-wrap: break-word;
+}

doc/howdoi.rst

@@ -0,0 +1,59 @@
+.. currentmodule:: xarray
+
+.. _howdoi:
+
+How do I ...
+============
+
+.. list-table::
+   :header-rows: 1
+   :widths: 40 60
+
+   * - How do I...
+     - Solution
+   * - add variables from other datasets to my dataset
+     - :py:meth:`Dataset.merge`
+   * - add a new dimension and/or coordinate
+     - :py:meth:`DataArray.expand_dims`, :py:meth:`Dataset.expand_dims`
+   * - add a new coordinate variable
+     - :py:meth:`DataArray.assign_coords`
+   * - change a data variable to a coordinate variable
+     - :py:meth:`Dataset.set_coords`
+   * - change the order of dimensions
+     - :py:meth:`DataArray.transpose`, :py:meth:`Dataset.transpose`
+   * - remove a variable from my object
+     - :py:meth:`Dataset.drop`, :py:meth:`DataArray.drop`
+   * - remove dimensions of length 1 or 0
+     - :py:meth:`DataArray.squeeze`, :py:meth:`Dataset.squeeze`
+   * - remove all variables with a particular dimension
+     - :py:meth:`Dataset.drop_dims`
+   * - convert non-dimension coordinates to data variables or remove them
+     - :py:meth:`DataArray.reset_coords`, :py:meth:`Dataset.reset_coords`
+   * - rename a variable, dimension or coordinate
+     - :py:meth:`Dataset.rename`, :py:meth:`DataArray.rename`, :py:meth:`Dataset.rename_vars`, :py:meth:`Dataset.rename_dims`,
+   * - convert a DataArray to Dataset or vice versa
+     - :py:meth:`DataArray.to_dataset`, :py:meth:`Dataset.to_array`
+   * - extract the underlying array (e.g. numpy or Dask arrays)
+     - :py:attr:`DataArray.data`
+   * - convert to and extract the underlying numpy array
+     - :py:attr:`DataArray.values`
+   * - find out if my xarray object is wrapping a Dask Array
+     - :py:func:`dask.is_dask_collection`
+   * - know how much memory my object requires
+     - :py:attr:`DataArray.nbytes`, :py:attr:`Dataset.nbytes`
+   * - convert a possibly irregularly sampled timeseries to a regularly sampled timeseries
+     - :py:meth:`DataArray.resample`, :py:meth:`Dataset.resample` (see :ref:`resampling` for more)
+   * - apply a function on all data variables in a Dataset
+     - :py:meth:`Dataset.apply`
+   * - write xarray objects with complex values to a netCDF file
+     - :py:func:`Dataset.to_netcdf`, :py:func:`DataArray.to_netcdf` specifying ``engine="h5netcdf", invalid_netcdf=True``
+   * - make xarray objects look like other xarray objects
+     - :py:func:`~xarray.ones_like`, :py:func:`~xarray.zeros_like`, :py:func:`~xarray.full_like`, :py:meth:`Dataset.reindex_like`, :py:meth:`Dataset.interpolate_like`, :py:meth:`Dataset.broadcast_like`, :py:meth:`DataArray.reindex_like`, :py:meth:`DataArray.interpolate_like`, :py:meth:`DataArray.broadcast_like`
+   * - replace NaNs with other values
+     - :py:meth:`Dataset.fillna`, :py:meth:`Dataset.ffill`, :py:meth:`Dataset.bfill`, :py:meth:`Dataset.interpolate_na`, :py:meth:`DataArray.fillna`, :py:meth:`DataArray.ffill`, :py:meth:`DataArray.bfill`, :py:meth:`DataArray.interpolate_na`
+   * - extract the year, month, day or similar from a DataArray of time values
+     - ``obj.dt.month`` for example where ``obj`` is a :py:class:`~xarray.DataArray` containing ``datetime64`` or ``cftime`` values. See :ref:`dt_accessor` for more.
+   * - round off time values to a specified frequency
+     - ``obj.dt.ceil``, ``obj.dt.floor``, ``obj.dt.round``. See :ref:`dt_accessor` for more.
+   * - make a mask that is ``True`` where an object contains any of the values in a array
+     - :py:meth:`Dataset.isin`, :py:meth:`DataArray.isin`

doc/index.rst

@@ -84,6 +84,7 @@ Documentation
 **Help & reference**
 
 * :doc:`whats-new`
+* :doc:`howdoi`
 * :doc:`api`
 * :doc:`internals`
 * :doc:`roadmap`
@@ -96,6 +97,7 @@ Documentation
    :caption: Help & reference
 
    whats-new
+   howdoi
    api
    internals
    roadmap

doc/time-series.rst

@@ -101,6 +101,8 @@ You can also select a particular time by indexing with a
 
 For more details, read the pandas documentation.
 
+.. _dt_accessor:
+
 Datetime components
 -------------------
 

doc/whats-new.rst

@@ -33,7 +33,8 @@ Documentation
 
 - Created a glossary of important xarray terms (:issue:`2410`, :pull:`3352`).
   By `Gregory Gundersen <https://github.com/gwgundersen/>`_.
-
+- Created a "How do I..." section (:ref:`howdoi`) for solutions to common questions. (:pull:`3357`).
+  By `Deepak Cherian <https://github.com/dcherian/>`_.
 - Add examples for :py:meth:`Dataset.swap_dims` and :py:meth:`DataArray.swap_dims`.
   By `Justus Magin <https://github.com/keewis>`_.
 - Add examples for :py:meth:`align`, :py:meth:`merge`, :py:meth:`combine_by_coords`,