xorbits.numpy.count_nonzero#

xorbits.numpy.count_nonzero(a, axis=None, combine_size=None)[源代码]#

Counts the number of non-zero values in the array a.

The word “non-zero” is in reference to the Python 2.x built-in method __nonzero__() (renamed __bool__() in Python 3.x) of Python objects that tests an object’s “truthfulness”. For example, any number is considered truthful if it is nonzero, whereas any string is considered truthful if it is not the empty string. Thus, this function (recursively) counts how many elements in a (and in sub-arrays thereof) have their __nonzero__() or __bool__() method evaluated to True.

参数

  • a (array_like) – The array for which to count non-zeros.

  • axis (int or tuple, optional) –

    Axis or tuple of axes along which to count non-zeros. Default is None, meaning that non-zeros will be counted along a flattened version of a.

    1.12.0(numpy) 新版功能.

  • keepdims (bool, optional (Not supported yet)) –

    If this is set to True, the axes that are counted are left in the result as dimensions with size one. With this option, the result will broadcast correctly against the input array.

    1.19.0(numpy) 新版功能.

返回

count – Number of non-zero values in the array along a given axis. Otherwise, the total number of non-zero values in the array is returned.

返回类型

int or array of int

参见

nonzero

Return the coordinates of all the non-zero values.

实际案例

>>> np.count_nonzero(np.eye(4))  
4
>>> a = np.array([[0, 1, 7, 0],  
...               [3, 0, 2, 19]])
>>> np.count_nonzero(a)  
5
>>> np.count_nonzero(a, axis=0)  
array([1, 1, 2, 1])
>>> np.count_nonzero(a, axis=1)  
array([2, 3])
>>> np.count_nonzero(a, axis=1, keepdims=True)  
array([[2],
       [3]])
combine_size: int, optional

The number of chunks to combine.

This docstring was copied from numpy.