SciPy

This is documentation for an old release of NumPy (version 1.9.0). Read this page in the documentation of the latest stable release (version > 1.17).

numpy.atleast_3d

numpy.atleast_3d(*arys)[source]

View inputs as arrays with at least three dimensions.

Parameters:

arys1, arys2, ... : array_like

One or more array-like sequences. Non-array inputs are converted to arrays. Arrays that already have three or more dimensions are preserved.

Returns:

res1, res2, ... : ndarray

An array, or tuple of arrays, each with a.ndim >= 3. Copies are avoided where possible, and views with three or more dimensions are returned. For example, a 1-D array of shape (N,) becomes a view of shape (1, N, 1), and a 2-D array of shape (M, N) becomes a view of shape (M, N, 1).

Examples

>>>
>>> np.atleast_3d(3.0)
array([[[ 3.]]])
>>>
>>> x = np.arange(3.0)
>>> np.atleast_3d(x).shape
(1, 3, 1)
>>>
>>> x = np.arange(12.0).reshape(4,3)
>>> np.atleast_3d(x).shape
(4, 3, 1)
>>> np.atleast_3d(x).base is x
True
>>>
>>> for arr in np.atleast_3d([1, 2], [[1, 2]], [[[1, 2]]]):
...     print arr, arr.shape
...
[[[1]
  [2]]] (1, 2, 1)
[[[1]
  [2]]] (1, 2, 1)
[[[1 2]]] (1, 1, 2)

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