numpy.diff()

numpy.diff(a, n=1, axis=-1) [source]

Calculate the n-th discrete difference along given axis.

The first difference is given by out[n] = a[n+1] - a[n] along the given axis, higher differences are calculated by using diff recursively.

Parameters:

Parameters:	a : array_like Input array `n : int, optional` The number of times values are differenced. `axis : int, optional` The axis along which the difference is taken, default is the last axis.
Returns:	diff : ndarray The n-th differences. The shape of the output is the same as `a` except along `axis` where the dimension is smaller by `n`. .

a : array_like

Input array

n : int, optional: The number of times values are differenced.
axis : int, optional: The axis along which the difference is taken, default is the last axis.

Returns:

diff : ndarray

The n-th differences. The shape of the output is the same as a except along axis where the dimension is smaller by n.

>>> x = np.array([1, 2, 4, 7, 0])
>>> np.diff(x)
array([ 1,  2,  3, -7])
>>> np.diff(x, n=2)
array([  1,   1, -10])

>>> x = np.array([[1, 3, 6, 10], [0, 5, 6, 8]])
>>> np.diff(x)
array([[2, 3, 4],
       [5, 1, 2]])
>>> np.diff(x, axis=0)
array([[-1,  2,  0, -2]])

Links:

doc_NumPy

2017-01-10 18:13:41

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