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# scipy.ndimage.sum

`scipy.ndimage.``sum`(input, labels=None, index=None)

  Calculate the sum of the values of the array.

  Parameters: | input : array_like Values of input inside the regions defined by labels are summed together. labels : array_like of ints, optional Assign labels to the values of the array. Has to have the same shape as input. index : array_like, optional A single label number or a sequence of label numbers of the objects to be measured.
  Returns: | sum : ndarray or scalar An array of the sums of values of input inside the regions defined by labels with the same shape as index. If ‘index’ is None or scalar, a scalar is returned.

  See also

  `mean`, `median`

  Examples

      >>> from scipy import ndimage
      >>> input =  [0,1,2,3]
      >>> labels = [1,1,2,2]
      >>> ndimage.sum(input, labels, index=[1,2])
      [1.0, 5.0]
      >>> ndimage.sum(input, labels, index=1)
      1
      >>> ndimage.sum(input, labels)
      6