mxnet.np.expand_dims

expand_dims(a, axis)

Expand the shape of an array.

Insert a new axis that will appear at the axis position in the expanded array shape.

Parameters

  • a (ndarray) – Input array.

  • axis (int) – Position in the expanded axes where the new axis is placed.

Returns

res – Output array. The number of dimensions is one greater than that of the input array.

Return type

ndarray

See also

squeeze()

The inverse operation, removing singleton dimensions

reshape()

Insert, remove, and combine dimensions, and resize existing ones

Examples

>>> x = np.array([1,2])
>>> x.shape
(2,)

>>> y = np.expand_dims(x, axis=0)
>>> y
array([[1., 2.]])

>>> y.shape
(1, 2)

>>> y = np.expand_dims(x, axis=1)  # Equivalent to x[:,np.newaxis]
>>> y
array([[1.],
       [2.]])

>>> y.shape
(2, 1)

Note that some examples may use None instead of np.newaxis. These are the same objects:

>>> np.newaxis is None
True