xarray.Dataset.assign_coords

Dataset.assign_coords(**kwargs)

Assign new coordinates to this object.

Returns a new object with all the original data in addition to the new coordinates.

Parameters
kwargskeyword, value pairs

keywords are the variables names. If the values are callable, they are computed on this object and assigned to new coordinate variables. If the values are not callable, (e.g. a DataArray, scalar, or array), they are simply assigned.

Returns
assignedsame type as caller

A new object with the new coordinates in addition to the existing data.

Notes

Since kwargs is a dictionary, the order of your arguments may not be preserved, and so the order of the new variables is not well defined. Assigning multiple variables within the same assign_coords is possible, but you cannot reference other variables created within the same assign_coords call.

Examples

Convert longitude coordinates from 0-359 to -180-179:

>>> da = xr.DataArray(np.random.rand(4),
...                   coords=[np.array([358, 359, 0, 1])],
...                   dims='lon')
>>> da
<xarray.DataArray (lon: 4)>
array([0.28298 , 0.667347, 0.657938, 0.177683])
Coordinates:
  * lon      (lon) int64 358 359 0 1
>>> da.assign_coords(lon=(((da.lon + 180) % 360) - 180))
<xarray.DataArray (lon: 4)>
array([0.28298 , 0.667347, 0.657938, 0.177683])
Coordinates:
  * lon      (lon) int64 -2 -1 0 1