numpy.reshape(a, newshape, order='C')
[source]
Gives a new shape to an array without changing its data.
Parameters: 


Returns: 

See also
ndarray.reshape
It is not always possible to change the shape of an array without copying the data. If you want an error to be raised when the data is copied, you should assign the new shape to the shape attribute of the array:
>>> a = np.zeros((10, 2)) # A transpose makes the array noncontiguous >>> b = a.T # Taking a view makes it possible to modify the shape without modifying # the initial object. >>> c = b.view() >>> c.shape = (20) Traceback (most recent call last): ... AttributeError: incompatible shape for a noncontiguous array
The order
keyword gives the index ordering both for fetching the values from a
, and then placing the values into the output array. For example, let’s say you have an array:
>>> a = np.arange(6).reshape((3, 2)) >>> a array([[0, 1], [2, 3], [4, 5]])
You can think of reshaping as first raveling the array (using the given index order), then inserting the elements from the raveled array into the new array using the same kind of index ordering as was used for the raveling.
>>> np.reshape(a, (2, 3)) # Clike index ordering array([[0, 1, 2], [3, 4, 5]]) >>> np.reshape(np.ravel(a), (2, 3)) # equivalent to C ravel then C reshape array([[0, 1, 2], [3, 4, 5]]) >>> np.reshape(a, (2, 3), order='F') # Fortranlike index ordering array([[0, 4, 3], [2, 1, 5]]) >>> np.reshape(np.ravel(a, order='F'), (2, 3), order='F') array([[0, 4, 3], [2, 1, 5]])
>>> a = np.array([[1,2,3], [4,5,6]]) >>> np.reshape(a, 6) array([1, 2, 3, 4, 5, 6]) >>> np.reshape(a, 6, order='F') array([1, 4, 2, 5, 3, 6])
>>> np.reshape(a, (3,1)) # the unspecified value is inferred to be 2 array([[1, 2], [3, 4], [5, 6]])
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https://docs.scipy.org/doc/numpy1.17.0/reference/generated/numpy.reshape.html