numpy.ediff1d — NumPy v1.11 Manual (original) (raw)
numpy.ediff1d(ary, to_end=None, to_begin=None)[source]¶
The differences between consecutive elements of an array.
| Parameters: | ary : array_like If necessary, will be flattened before the differences are taken. to_end : array_like, optional Number(s) to append at the end of the returned differences. to_begin : array_like, optional Number(s) to prepend at the beginning of the returned differences. |
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| Returns: | ediff1d : ndarray The differences. Loosely, this is ary.flat[1:] - ary.flat[:-1]. |
Notes
When applied to masked arrays, this function drops the mask information if the to_begin and/or to_end parameters are used.
Examples
x = np.array([1, 2, 4, 7, 0]) np.ediff1d(x) array([ 1, 2, 3, -7])
np.ediff1d(x, to_begin=-99, to_end=np.array([88, 99])) array([-99, 1, 2, 3, -7, 88, 99])
The returned array is always 1D.
y = [[1, 2, 4], [1, 6, 24]] np.ediff1d(y) array([ 1, 2, -3, 5, 18])