larray.isnan(x, /, out=None, *, where=True, casting='same_kind', order='K', dtype=None, subok=True[, signature, extobj])

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

larray specific variant of numpy.isnan.

Documentation from numpy:


Input array.

outndarray, None, or tuple of ndarray and None, optional

A location into which the result is stored. If provided, it must have a shape that the inputs broadcast to. If not provided or None, a freshly-allocated array is returned. A tuple (possible only as a keyword argument) must have length equal to the number of outputs.

wherearray_like, optional

Values of True indicate to calculate the ufunc at that position, values of False indicate to leave the value in the output alone.


For other keyword-only arguments, see the ufunc docs.

yndarray or bool

True where x is NaN, false otherwise. This is a scalar if x is a scalar.

See also

isinf, isneginf, isposinf, isfinite, isnat


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])