numpy.expand_dims(a, axis)[source]
Expand the shape of an array.
Insert a new axis, corresponding to a given position in the array shape.
Parameters: |
a : array_like Input array. axis : int Position (amongst axes) where new axis is to be inserted. |
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Returns: |
res : ndarray Output array. The number of dimensions is one greater than that of the input array. |
See also
>>> x = np.array([1,2]) >>> x.shape (2,)
The following is equivalent to x[np.newaxis,:]
or x[np.newaxis]
:
>>> 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[:,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
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https://docs.scipy.org/doc/numpy-1.11.0/reference/generated/numpy.expand_dims.html