Numpy flat flatten 将多维数组压平为一维

temp = np.array([[1,2,3,4],[5,6,7,8]])

print("temp.flat",temp.flat)  # temp.flat 返回的是一维迭代器
print("type(temp.flat)",type(temp.flat))
print("list((temp.flat))",list((temp.flat)))

print("temp",temp)

print("---")

temp_new = temp.flatten()  # 返回一维的副本
print("temp.flatten()",temp_new)
print("temp",temp)
print("temp_new",temp_new)

temp.flat <numpy.flatiter object at 0x55d8a1a049e0>
type(temp.flat) <class 'numpy.flatiter'>
list((temp.flat)) [1, 2, 3, 4, 5, 6, 7, 8]
temp [[1 2 3 4]
 [5 6 7 8]]
---
temp.flatten() [1 2 3 4 5 6 7 8]
temp [[1 2 3 4]
 [5 6 7 8]]
temp_new [1 2 3 4 5 6 7 8]

 |  flat : numpy.flatiter object
 |      Flattened version of the array as an iterator.  The iterator
 |      allows assignments, e.g., ``x.flat = 3`` (See `ndarray.flat` for
 |      assignment examples; TODO).

help(np.array([]).flatten)
Help on built-in function flatten:

flatten(...) method of numpy.ndarray instance
    a.flatten(order='C')
    
    Return a copy of the array collapsed into one dimension.
    
    Parameters
    ----------
    order : {'C', 'F', 'A', 'K'}, optional
        'C' means to flatten in row-major (C-style) order.
        'F' means to flatten in column-major (Fortran-
        style) order. 'A' means to flatten in column-major
        order if `a` is Fortran *contiguous* in memory,
        row-major order otherwise. 'K' means to flatten
        `a` in the order the elements occur in memory.
        The default is 'C'.
    
    Returns
    -------
    y : ndarray
        A copy of the input array, flattened to one dimension.
    
    See Also
    --------
    ravel : Return a flattened array.
    flat : A 1-D flat iterator over the array.
    
    Examples
    --------
    >>> a = np.array([[1,2], [3,4]])
    >>> a.flatten()
    array([1, 2, 3, 4])
    >>> a.flatten('F')
    array([1, 3, 2, 4])