将列表数组转换为元组数组/trip

Question

我有一个有3列的2D Numpy数组。它看起来像这样array([[0, 20, 1], [1,2,1], ........, [20,1,1]])。它基本上是列表的数组。如何将此矩阵转换为array([(0,20,1), (1,2,1), ........., (20,1,1)])？我希望输出是一个三元组的数组。我一直在尝试使用Convert numpy array to tuple中描述的元组和映射函数

R = mydata #my data is sparse matrix of 1's and 0's
#First row
#R[0] = array([0,0,1,1]) #Just a sample
(rows, cols) = np.where(R)
vals = R[rows, cols]
QQ = zip(rows, cols, vals)
QT = tuple(map(tuple, np.array(QQ))) #type of QT is tuple

QTA = np.array(QT) #type is array
#QTA gives an array of lists
#QTA[0] = array([0, 2, 1])
#QTA[1] = array([0, 3, 1])

但是期望的输出是QTA应该是元组数组，即QTA=array（[（0,2,1），（0,3,1）]）。在

Answer 1

不是很好的解决方案，但这会奏效：

# take from your sample
>>>a = np.array([[0, 20, 1], [1,2,1], [20,1,1]]) 

# construct an empty array with matching length
>>>b = np.empty((3,), dtype=tuple)

# manually put values into tuple and store in b
>>>for i,n in enumerate(a):
>>>    b[i] = (n[0],n[1],n[2])

>>>b
array([(0, 20, 1), (1, 2, 1), (20, 1, 1)], dtype=object)

>>>type(b)
numpy.ndarray