nums.numpy.expand_dims

nums.numpy.expand_dims(a, axis)[source]

Expand the shape of an array.

This docstring was copied from numpy.expand_dims.

Some inconsistencies with the NumS version may exist.

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

Parameters

  • a (BlockArray) – Input array.

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

Returns

result – View of a with the number of dimensions increased.

Return type

BlockArray

See also

squeeze

The inverse operation, removing singleton dimensions

reshape

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

atleast_1d, atleast_2d, atleast_3d

Examples

The doctests shown below are copied from NumPy. They won’t show the correct result until you operate get().

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

The following is equivalent to x[nps.newaxis, :] or x[nps.newaxis]:

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

The following is equivalent to x[:, nps.newaxis]:

>>> y = nps.expand_dims(x, axis=1)  
>>> y.get()  
array([[1],
       [2]])
>>> y.shape  
(2, 1)

axis may also be a tuple:

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

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