mxnet.np.bincount

bincount(x, weights=None, minlength=0)

Count number of occurrences of each value in array of non-negative ints.

Parameters
  • x (ndarray) – input array, 1 dimension, nonnegative ints.

  • weights (ndarray) – input weigths same shape as x. (Optional)

  • minlength (int) – A minimum number of bins for the output. (Optional)

Returns

out – the result of binning the input array. The length of out is equal to amax(x)+1.

Return type

ndarray

Raises
  • Value Error – If the input is not 1-dimensional, or contains elements with negative values, or if minlength is negative

  • TypeError – If the type of the input is float or complex.

Examples

>>> np.bincount(np.arange(5))
array([1, 1, 1, 1, 1])
>>> np.bincount(np.array([0, 1, 1, 3, 2, 1, 7]))
array([1, 3, 1, 1, 0, 0, 0, 1])
>>> x = np.array([0, 1, 1, 3, 2, 1, 7, 23])
>>> np.bincount(x).size == np.amax(x)+1
True
>>> np.bincount(np.arange(5, dtype=float))
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: array cannot be safely cast to required type
>>> w = np.array([0.3, 0.5, 0.2, 0.7, 1., -0.6]) # weights
>>> x = np.array([0, 1, 1, 2, 2, 2])
>>> np.bincount(x,  weights=w)
array([ 0.3,  0.7,  1.1])