python迭代器用法itertools

mat=[[1,1,1,1],[2,2,2,2],[3,3,3,3],[4,4,4,4]]

m, n = len(mat), len(mat[0])

s = [[0] * (n + 1)] + [[0, *itertools.accumulate(row)] for row in mat]

[[*itertools.accumulate(i)] for i in [[1,2,3,4]]]

[*itertools.accumulate([1,2,3])]

[*range(3)]

product

for i,j in itertools.product(range(1,5),range(1,5)):

print((i,j))