dask.array.nansum
dask.array.nansum¶
- dask.array.nansum(a, axis=None, dtype=None, keepdims=False, split_every=None, out=None)[source]¶
Return the sum of array elements over a given axis treating Not a Numbers (NaNs) as zero.
This docstring was copied from numpy.nansum.
Some inconsistencies with the Dask version may exist.
In NumPy versions <= 1.9.0 Nan is returned for slices that are all-NaN or empty. In later versions zero is returned.
- Parameters
- aarray_like
Array containing numbers whose sum is desired. If a is not an array, a conversion is attempted.
- axis{int, tuple of int, None}, optional
Axis or axes along which the sum is computed. The default is to compute the sum of the flattened array.
- dtypedata-type, optional
The type of the returned array and of the accumulator in which the elements are summed. By default, the dtype of a is used. An exception is when a has an integer type with less precision than the platform (u)intp. In that case, the default will be either (u)int32 or (u)int64 depending on whether the platform is 32 or 64 bits. For inexact inputs, dtype must be inexact.
New in version 1.8.0.
- outndarray, optional
Alternate output array in which to place the result. The default is
None
. If provided, it must have the same shape as the expected output, but the type will be cast if necessary. See Output type determination for more details. The casting of NaN to integer can yield unexpected results.New in version 1.8.0.
- keepdimsbool, optional
If this is set to True, the axes which are reduced are left in the result as dimensions with size one. With this option, the result will broadcast correctly against the original a.
If the value is anything but the default, then keepdims will be passed through to the mean or sum methods of sub-classes of ndarray. If the sub-classes methods does not implement keepdims any exceptions will be raised.
New in version 1.8.0.
- initialscalar, optional (Not supported in Dask)
Starting value for the sum. See ~numpy.ufunc.reduce for details.
New in version 1.22.0.
- wherearray_like of bool, optional (Not supported in Dask)
Elements to include in the sum. See ~numpy.ufunc.reduce for details.
New in version 1.22.0.
- Returns
- nansumndarray.
A new array holding the result is returned unless out is specified, in which it is returned. The result has the same size as a, and the same shape as a if axis is not None or a is a 1-d array.
See also
Notes
If both positive and negative infinity are present, the sum will be Not A Number (NaN).
Examples
>>> import numpy as np >>> np.nansum(1) 1 >>> np.nansum([1]) 1 >>> np.nansum([1, np.nan]) 1.0 >>> a = np.array([[1, 1], [1, np.nan]]) >>> np.nansum(a) 3.0 >>> np.nansum(a, axis=0) array([2., 1.]) >>> np.nansum([1, np.nan, np.inf]) inf >>> np.nansum([1, np.nan, -np.inf]) -inf >>> from numpy.testing import suppress_warnings >>> with np.errstate(invalid="ignore"): ... np.nansum([1, np.nan, np.inf, -np.inf]) # both +/- infinity present np.float64(nan)