如何计算下面数组中0和1的个数？

y = np.array([0, 0, 0, 1, 0, 1, 1, 0, 0, 0, 0, 1])

y.count(0) 给出:

numpy.ndarray object has no attribute count

最佳答案

使用 numpy.unique :

import numpy
a = numpy.array([0, 3, 0, 1, 0, 1, 2, 1, 0, 0, 0, 0, 1, 3, 4])
unique, counts = numpy.unique(a, return_counts=True)

>>> dict(zip(unique, counts))
{0: 7, 1: 4, 2: 1, 3: 2, 4: 1}

非numpy方法使用collections.Counter ;

import collections, numpy
a = numpy.array([0, 3, 0, 1, 0, 1, 2, 1, 0, 0, 0, 0, 1, 3, 4])
counter = collections.Counter(a)

>>> counter
Counter({0: 7, 1: 4, 3: 2, 2: 1, 4: 1})

https://stackoverflow.com/questions/28663856/