how to select subset of data in a dataset using xarray code example

Example 1: how to select subset of data in a dataset using xarray

#import xarray
import xarray as xr

#open the dataset
ds = xr.open_dataset(file_name.nc)

#get a subset of the data
ds.sel(dim=slice()) # input the dimension (dim) to select and the value of the dimension into the slice function(slice)
ds.loc[{'dim': slice()}]
ds.where(bool array) #locate the values based on a condition

#examples
ds[var_name].loc[{'latitude': slice(60,48),
                  'longitude': slice(-12,5)}]

ds.where(ds[var_name] > 0.1)
#the example will return a subset of the dataset where the latitude
#and longitude are of the requirements stated in the slice function

Example 2: how to select variables in a dataset using xarray

#import xarray
import xarray as xr

#open the dataset
ds = xr.open_dataset(file_name.nc)

#var_name in the following table is to be entered as a string

selection         |    syntax                     |    returns
--------------------------------------------------------------
single variable   | ds[var_name]                  | DataArray
--------------------------------------------------------------
single variable   | ds[[var_name]]                | Dataset
--------------------------------------------------------------
multiple variable | ds[[var_name1, var_name2...]] | Dataset