xarray.ufuncs.isnan = <xarray.ufuncs._UFuncDispatcher object>

xarray specific variant of numpy.isnan. Handles xarray.Dataset, xarray.DataArray, xarray.Variable, numpy.ndarray and dask.array.Array objects with automatic dispatching.

Documentation from numpy:

isnan(x[, out])

Test element-wise for NaN and return result as a boolean array.


x : array_like

Input array.


y : ndarray or bool

For scalar input, the result is a new boolean with value True if the input is NaN; otherwise the value is False.

For array input, the result is a boolean array of the same dimensions as the input and the values are True if the corresponding element of the input is NaN; otherwise the values are False.

See also

isinf, isneginf, isposinf, isfinite


Numpy uses the IEEE Standard for Binary Floating-Point for Arithmetic (IEEE 754). This means that Not a Number is not equivalent to infinity.


>>> np.isnan(np.nan)
>>> np.isnan(np.inf)
>>> np.isnan([np.log(-1.),1.,np.log(0)])
array([ True, False, False], dtype=bool)