numpy數組擴展函數repeat和tile用法

numpy.repeat(a, repeats, axis=None)

 

>>> a = np.arange(3) >>> a array([0, 1, 2]) >>> np.repeat(a, 2) array([0, 0, 1, 1, 2, 2])

>>> a = [[0,1], [2,3], [4,5]]
>>> y = np.repeat(a, 2)
>>> y
array([0, 0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5])
>>> x = np.tile(a, (2,1))
>>> x
array([[0, 1],
       [2, 3],
       [4, 5],
       [0, 1],
       [2, 3],
       [4, 5]])


>>> a = np.array([[1,2],[3,4]])
>>> a
array([[1, 2],
       [3, 4]])
>>> np.repeat(a, 2, 1)
array([[1, 1, 2, 2],
       [3, 3, 4, 4]])

>>> np.repeat(a, 2, 0)
array([[1, 2],
       [1, 2],
       [3, 4],
       [3, 4]])

 

tile函數功能：對整個數組進行復制拼接

>>> a array([[1, 2], [3, 4]]) >>> np.tile(a, 2) array([[1, 2, 1, 2], [3, 4, 3, 4]])
#構造3*1個copy
>>> a = np.tile(a, (3, 1))
>>> a
array([[1, 2],
       [3, 4],
       [1, 2],
       [3, 4],
       [1, 2],
       [3, 4]])