How to count all the items in the python list without using loops

Question

How to count all the items in the python list

board = [
    [7,8,0,4,0,0,1,2,0],
    [6,0,0,0,7,5,0,0,9],
    [0,0,0,6,0,1,0,7,8],
    [0,0,7,0,4,0,2,6,0],
    [0,0,1,0,5,0,9,3,0],
    [9,0,4,0,6,0,0,0,5],
    [0,7,0,3,0,0,0,1,2],
    [1,2,0,0,0,7,4,0,0],
    [0,4,9,2,0,6,0,0,7]
]

print(len(board)) #prints 9 as the length of list

How do I print all the available items in the list (91) (without using any loop)

Answer 1

可以使用itertools.chain.from_iterable将列表展平，然后正常计数和打印——

print(len(list(itertools.chain.from_iterable(board))))

Answer 2

You could use a reduction , eg:

import functools


board = [
    [7,8,0,4,0,0,1,2,0],
    [6,0,0,0,7,5,0,0,9],
    [0,0,0,6,0,1,0,7,8],
    [0,0,7,0,4,0,2,6,0],
    [0,0,1,0,5,0,9,3,0],
    [9,0,4,0,6,0,0,0,5],
    [0,7,0,3,0,0,0,1,2],
    [1,2,0,0,0,7,4,0,0],
    [0,4,9,2,0,6,0,0,7]
]


length = functools.reduce(lambda total, item: total + len(item), board, 0)
print(length)
# 81

Answer 3

import functools 

arr_len = functools.reduce(lambda a,b : len(a)+len(b),board)) 

Answer 4

sum(list(map(len,board))) 

works as well

output:

81